Chemistry (Redox)

Chemistry (Redox)
Experiment 1 : Redox Titration Using Sodium Thiosulphate
Abstract
This experiment is to determine the concentration of oxidizing solution using the iodine/
thiosulphate titration where the reducing solution is potassium iodate solution and the oxidizing
solution is sodium thiosulphate solution. Potassium iodate solution which is an oxidizing agent is
added into an excess solution of acidified potassium iodide. This reaction will release iodine.
Potassium iodide is acidified with sulphuric acid and the iodine released quickly titrated with
sodium thiosulphate until it become light yellow. The iodine then detected with starch solution and
it turn into dark blue solution and titrated again with sodium thiosulphate until colourless. From ...
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B.Standardization of 0.1M sodium thiosulphate solution 1. A burette is filled with the 0.1M sodium
thiosulphate solution to be standardized. There are no air bubbles in the burette. 2. The initial
reading of the burette is recorded in table 1.1. 3. 25–mL of standard potassium iodate solution
prepared in part A are pipetted into a 250–mL conical flask and a magnetic flea is added into conical
flask. 4. 1 g of potassium iodide, KI, is weighed approximately and it is placed in a 50–mL beaker.
5. 10.0 mL of 1.0M sulphuric acid solution are added and are swirled until all the KI dissolved. 6.
This solution is added to the conical flask containing the potassium iodate solution and it is
immediately titrated with the sodium thiosulphate solution, while it is stirred using a stirrer hot
plate, until a ligth yellow solution is obtained. Then, the solution is diluted with distilled water until
the total volume is about 100 mL. Then, 1.0 mL of starch solution is added and the titration is
continued until the blue colour disappears and the solution become colourless. 7. The final reading
of the burette is recorded in the table 1.1 . The procedures are repeated twice as the results is more
accurate.
CALCULATIONS :
1. Complete chemical reaction equation for reaction between ; i. iodate and iodide
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Factors Affecting Rate of a Reaction, Chemistry Design Lab
Chemistry Lab Report
(Design)
Factors affecting Rates of a Reaction (Kinetics)
KINETICS DESIGN LAB
Research Question:
Does the concentration of Potassium Iodide (KI) affect the rate of its reaction with hydrogen
peroxide (H2O2) (of a fixed concentration)?
Introduction:
There are several factors that affect the rate of a reaction. Some of them being Pressure (if the
reactants are Gases), Temperature, Presence of a Catalyst, Surface Area of the reactant, and
Concentration. According to the Collision Theory, during a reaction, particles collide with each
other and react if the geometry of the collision is correct. In this Experiment, we will investigate the
effect of varying concentrations of Potassium Iodide on its reaction with ... Show more content on
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The Potassium Iodide particles will increase and the frequency of their collisions with Hydrogen
Peroxide particles will also increase, causing them to react quicker.
I hypothesize that as I increase the concentration of the Potassium Iodide Solution, the rate at which
the blue–black starch complex covers the 'X' marking on the tile, will also increase until a point
where the rate will remain the same due to all the particles having already finished reacting.
1

Investigate the rate of reaction between HCl and Na2S 2O3...
Investigate the rate of reaction between HCl and Na2S 2O3
For this piece of coursework we are investigating the rates of reaction and he effect different
changes have on them. The rate of reaction is the rate of loss of a reactant or the rate of formation of
a product during a chemical reaction. We are studying the affect of changing concentration of
Na2S2O3 Solution and dilute HCl.
I believe these variables will affect the rate of reaction:
· Surface area
· Pressure
· Temperature
· Catalyst
· Concentration
Concentration
=============
If the concentration of a solution is increased there are more reactant particles per unit volume. This
increased the probability of reactant particles colliding with each other. ... Show more content on
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During my preliminary experiment in which sulphur was made the speed at which the precipitate of
the solid was produced was used to measure the speed of the reaction.
Na2S2 O3(aq) + 2HCl(aq) 2NaCl(aq) + H2O(i) + SO2(g) + S(s)
Prediction
I predict that as the temperature is increased the rate of reaction will increase. I also predict that as
the concentration of the sodium thiosulphate increases the rate of reaction will increase. When the
temperature is increased the particles will have more energy and this would enable them to move
faster. This will make them collide more often and with more energy. Particles with more energy are
more likely to overcome the activation energy barrier to reaction; this would make them react
successfully. If solutions of reacting particles are made more concentrated there are more particles
in the area.

Method
Experiment 1 – Changing the concentration
5 cm3 of HCl (at concentration 1 mol./dm3) and 15 cm3 of sodium thiosulphate (at varying
concentrations – 10 to 35 g/dm3) are poured out into two measuring cylinders and then poured into
a conical flask, which is placed on top of a board marked with letter X. The stopwatch will now be
started. When the mixture has turned sufficiently cloudy so that the letter X can no longer be seen
the stopwatch will be stopped and the time will be recorded. The experiment is repeated

Investigating Reaction Rates of Sodium Thiosulphate and...
Investigating Reaction Rates of Sodium Thiosulphate and Hydrochloric Acid Aim: To investigate
the rate of reaction of Sodium Thiosulphate and Hydrochloric acid. In this investigation I will be
varying the concentration of Sodium Thiosulphate only and not the Hydrochloric acid concentration.
In this investigation I will use the following word equation: Sodium Thiosulphate + Hydrochloric
acid In this investigation I will use the following symbol equation: Na2S2O3 + Hcl Prediction: I
predict that as the Sodium Thiosulphate concentration increases the rate of reaction will also
increase. The reason I predict this is because there will be a higher concentration of ... Show more
content on Helpwriting.net ...
The collision theory explains all there is to the rate of reaction. The collision theory states that the
rate of reaction depends on how often and how hard the reacting particles collide. Reacting particles
need to collide with each other to be able to react. The more collisions there are then the faster the
rate of reaction will be. The following methods of increasing the rate of reaction can be explained
by increasing the number of collisions between the reacting particles: * Temperature– When the
temperature is increased in a reaction the particles begin to move around much quicker. This means
that when they collide with each other they will collide harder. * Catalyst– A catalyst works by
giving the reacting particles a surface to stick to on which they can collide with each other on. This
also increases the number of collisions between the particles. * Size– If one of the reactants is a
solid it will have a smaller surface area than a solid that is broken up into smaller pieces. This
allows the particles in the solution to have a bigger area to collide in. * Concentration– A more
concentrated solution means there are more reactant particles moving about amongst the water
particles. This makes collisions between the reactant particles more

Task 7 : Method Of An Copper Sulphate Solution Into A...
Task 7:
 Titrations:
Method:
1. Firstly you need to need to measure accurately 0.50g of your copper sulphate solution into a
100cm³ beaker
2. Then add about 50cm³ of distilled water ensuring you continue to stir until crystals have
dissolved. Then transfer the solution into a 100cm³ volumetric flask
3. Next rinse out the beaker with small amounts of distilled water and transfer the washings to the
volumetric flask to ensure none of the solution is wasted affecting the end result.
4. Once the beaker is sufficiently washed out make the volume in the flask up to the line with more
water. Then place a stopper in the flask and invert a few times to ensure the solution is mixed.
5. Then use a pipette and pipette filler to withdraw 10cm³of the solution and transfer it to a
100cm³conincal flask. Adding about 0.5g of solid potassium iodide to the conical flask ensuring to
swirl the contents so that the solution turns brown due to the formation of iodide with a beige
coloured precipitate of copper iodide.
6. Next fill a burette with 0.01mol of sodium thiosulphate ensuring you record the readings from the
burette and place them in an appropriate table.
7. Then add the sodium thiosulphate solution to the conical flask gradually until the iodine colour is
nearly removed. Then add 1cm³of starch solution and continue the titration until the blue–black
colour just goes. This indicates the end point.
8. Finally record the final burette reading and calculate the volume of sodium thiosulphate

Iodine Clock Reaction
Introduction:
First discovered by Hans Heinrich Landolt in the 19th century, the Iodine Clock reaction is what is
described as a chemical clock reaction, and today is one of only few known to science. It is useful as
a tool in determining the rate of a chemical reaction due to a marked change in the color of the
reacting solution when a particular reaction has been completed. The process is also practical as an
introduction to reaction rates and kinetics. A solution of hydrogen peroxide is mixed with one
containing potassium iodide, starch and sodium thiosulfate. After a varying amount of time the
colorless mixture suddenly turns dark blue which is one of a number of reactions related to the
iodine clock. The positive points of the lab would ... Show more content on Helpwriting.net ...
During the lab, a stopwatch was used to measure the time of the reaction taking place. The eye–hand
coordination of a human simply cannot be trusted to be entirely accurate which is why there was
uncertainty about the accuracy of the stopwatch.Although the conduction of this experiment was
straightforward, it would be better if we had access to more potassium iodide. The concentration of
potassium iodide was too low, and as a result it delayed the time that the reaction took place. For
example, in trial 2, the portion of sodium thiosulfate is higher than potassium iodide's, so the
reaction delayed. The concentration of potassium iodide would be higher if the potassium iodide
provided to us was not diluted. The potassium iodide provided was at a concentration of 0.2 moles
and if it were at a higher concentration, we would've gotten a quicker reaction.As an alternate
method for this lab, solid potassium iodide could be used instead of liquid potassium iodide since
the amount of solid potassium iodide can alter the concentration of the solution. In order to get solid
potassium iodide, we would boil liquid potassium iodide, and as a result, solid potassium iodide
would be left in the plate due to the evaporation of

The Presence Of Vitamin C
Introduction:
The presence of Vitamin C (Ascorbic Acid) in an individual's diet is critical since humans, in fact,
does not have the ability to synthesize them ourselves. Vitamin C is essential for human health. It is
an antioxidant scavenger and it is also vital for tissue maintenance and repair. The lack of Vitamin C
in one's system can lead to numerous kinds of illnesses. For example, severe Vitamin C in a
prolonged period can lead to scurvy.
Vitamin C can be obtained from fruit, vegetables, and lab made Vitamin C tablets. The synthesis of
Vitamin C supplements in the laboratory was found to be extremely efficient in 1933. They are now
largely manufactured in laboratories and sold to the market. However, degradation of Vitamin C
occurs over time. The rate of degradation will be accelerated when exposed to air, light, and heat.
Therefore, it is essential for the manufacturers to acknowledge the rate of degradation so they could
estimate how much Vitamin C should be made and when the expiry date should be.
In this experiment a solution of Vitamin C is added to a solution containing of known excess of
iodine. At this point, the solution will turn blue–black in colour and this excess amount of iodine can
then be titrated against standardized sodium thiosulphate. (^citation here) This technique is called
back–titration.
The Iodine is produced by the mixture of the following reagents: KIO3,KI,and H2SO4.
KIO3+ 5KI+ 3H2SO4 3I2+ 3K2SO4+ 3H2O(1)
Ascorbic acid+

Analysis of Commercial Vitamin C Tablets
Analysis of commercial vitamin C tablets
Objective
To determine the vitamin C content in commercial vitamin C tablets by titration between vitamin C
(ascorbic acid) & iodine solution. Hence, compare this data with the manufacturer 's specification.
Principle
In this analysis, certain amount of iodine solution, which is known in excess, is added to acidified
ascorbic acid solution. Brown iodine can be easily reduced by acidified ascorbic acid to form
colourless iodide ion: ← Equation I The excess iodine is then back titrated by standard sodium
thiosulphate solution, by using a burette and starch solution (used as end point indicator) Similarly,
iodine can also be ... Show more content on Helpwriting.net ...
of moles of I2 added to react with vitamin C = 9.550761x10–4 mol No. of moles of S2O32– reacted
by excess I2 = 0.064099M x 0.012175dm3 = 7.804061x10–4 mol From equation II, no. of moles of
excess I2 = 7.804061x10–4 ÷ 2 mol = 3.902030 x

The Kinetocs Experiment of Iodide Ions and Persulphate Ions.
The catalytic effect of D–block ions and the kinetics of reactions iodine clock reaction: By Stephen
Parsons 6K2 Centre number: 61813 Candidate number: 8270 Table of Contents My aim and my
reaction: 3 Rate of reaction: 4 Activation enthalpy: 5 Collision theory: 6 The effect of temperature
on reaction rate: 7 The effect of concentration on reaction rate: 7 The effect of a catalyst on reaction
rate: 8 D–block elements: 9 The effect of extra kinetic energy (from stirring etc.): 10 Where do we
use D–block ion catalysts? 10 Arrhenius equation: 12 Orders of reaction: 10 Oxidation states of D–
block ions: 13 Electronic configuration and transition metals: 13 Experiment: 13 Method: 14 Risk
assessment: 15 How to make my standard ... Show more content on Helpwriting.net ...
The temperature affects most reactions and increases there rates unless the reaction uses an enzyme
that only is effective up to or down to a certain temperature. This change has this effect because it
increases collision rate and speed so more collisions with the correct reaction energy occur so more
successful collisions occur increasing the reaction rate. The pressure is an important factor in gas
reactions because the gas concentration is proportional to pressure. The use of a catalyst affect
reaction rate by lowering the reaction enthalpy making the proportion of successful collisions
higher. Surface area of reactants is a key variable because a higher surface area provides a higher
chance of 2 reactants colliding and producing a successful reaction. Activation enthalpy: I just
talked a lot about activation enthalpy I will now explain what is meant by this. Activation enthalpy
is the minimum amount of kinetic energy required by a pair of colliding particles for a reaction to
occur. it is the amount of energy required for the particles of the reactants to break the bonds holding
them

Chemical Kinetics: The Iodine Clock
Chemical Engineering Department
FIRST YEAR LABORATOY REPORT #1
Name: Shams Alizada
Experiment Title: Chemical Kinetics: The Iodine Clock Experiment Date : 13 October 2016
Submission Date: 20 October 2016 Supervisor: Rashid Akhundov
Contents
Synopsis 2
Introduction. 3
Safety Precautions. 3
Theory 3
Experimental Technique 4
Equipment and Apparatus. 5
Experimental Procedure. 5
Results 6
Discussion 7
Conclusion 8
References 8
Synopsis
The experiment concerning the iodine clock reaction was carried out to find ... Show more content
on Helpwriting.net ...
Lime or soda must be poured on the contaminated floor and it must be cleaned until the floor gets
dry. While using pipette during an experiment, the starch solutions must be pipetted using the rubber
suction bulb, the solutions must not be pipetted by mouth. After checking the color and time, all the
solutions must be disposed in the aqueous residue bottle.
Theory
Iodine Clock is the reaction which includes the colorless compounds and after mixture, observance
the appearance of color in the solution: dark blue/purple. The color, depending on the temperature
and the concentration of the substances which react with one another, appears in a short time

interval. Rate of reaction for the experiment is calculated in the equation given below: reaction
rate=k×〖[A]〗^m×〖[B]〗^n
Here, m and n are called –reaction order, k is called– rate constant which depends on temperature.
There are the factors that can have impacts on the reaction rate of the compounds. As mentioned in
the collision theory (John Green & Sadru Damji), (Green, 2014) these factors involve the
concentration of substances. This experiment will also determine the concentration of H_2 O_2 on
iodide

Lab Report Chemistry
1. Describe what the results were.
According to the results, the higher the concentration of sodium thiosulphate the higher the reaction
rate. The graph above shows the reaction rate compared to the sodium thiosulphate solution is
almost a straight line showing the relationship of the sodium thiosulphate and the rate of reaction.
2. Explain why the results were the way they were
The higher the sodium thiosulphate concentration the faster the rate of the chemical reaction as
more particle collide. The graph shows a liner relationship as the sodium thiosulphate concentration
was diluted at the same rate every time the experiment was done using veering concentrations.
3. Were the results surprising? Why/why not?
The results were not particularly surprising as the concentration of the sodium thiosulphate was
known to have an effect on the ... Show more content on Helpwriting.net ...
This is known because the recorded points of data lay close to liner best fit for the set of data.
However to make the results more accurate the experiment should have been repeated at least 2–3
more times to make sure that the answers found where correct and not just a one off occurrence.
5. Were there any problems or difficulties encountered in the experiment? Explain how the how they
may have affected your results.
The main difficulty was with determining when the visibility was the same for each chemical
reaction and concentration. In the end this was done by drawing a cross to put underneath each of
the concentrations, when the cross was no longer visible by the naked eye from the top of the
chronical flask the time was taken and recorded. Even as it was the same person judging how long it
took for the cross to disappear and if the cross was still visible was still controversial. This was the
main problem that could have been solved with more tests of each concentration and then averaging
it out.
6. If this was attempted again, explain what improvements you would make to the experiment

The Effect Temperature and Concentration Have on a Reaction
The Effect Temperature and Concentration Have on a Reaction We must produce a piece of
coursework investigating the rates of reaction, and the effect different changes have on them. The
rate of reaction is the rate of loss of a reactant or the rate of formation of a product during a
chemical reaction. It is measured by dividing 1 by the time taken for the reaction to take place.
There is five factors which affect the rate of a reaction, according to the collision theory of reacting
particles: temperature, concentration (of solution), pressure (in gases), surface are (of solid
reactants), and catalysts. I have chosen to investigate the ... Show more content on Helpwriting.net
...
The whole procedure is then repeated.
Experiment 2 – Changing the temperature
5 cm of HCl (at concentration 1 mol./dm3) and 15 cm of sodium thiosulphate (at varying
concentrations – 10 to 35 g/dm3) are poured out into two measuring cylinders. A beaker is half filled
with hot water from a tap. The water is placed on top of a Bunsen on a blue flame and the two
measuring placed inside the water bath. The water is heated to the necessary temperature (30ºC to
70ºC) then the two measuring cylinders are taken out and the contents of both are poured into a
conical cylinder. The time it takes for the X to disappear is timed and recorded. The experiment is
repeated using all the temperatures. The entire procedure is the repeated.
Repeat results and averages will be taken to improve the credibility of the findings, and present
solid grounding for the final conclusion. The repeat results will help to iron out any anomalies and
the average will give a good summary of the results of the experiment. However if one set of results
is entirely different to the other, a third experiment will be performed to replace the anomalous set
of results.
Safety – A pair of goggles will be worn during the heating part of the experiment in order to protect
the eyes. An apron will also be worn to protect the skin and clothing. When handling hot beakers
and measuring cylinders a pair

Supersaturated Lab
Unsaturated, Saturated, And Supersaturated Solutions Lab
Purpose: The purpose of this lab was to see the differences between unsaturated, saturated, and
supersaturated solutions.
Brief Background: The concepts used in this lab are solutions and solubility. Within a solution there
is a solvent and a solute. In this lab, the solvent was the distilled water and the solute was the
sodium thiosulphate pentahydrate. Within each test tube we dissolved sodium thiosulphate
pentahydrate with water to create a solution which was either saturated, unsaturated, or
supersaturated. Saturated is when the solution contains the maximum amount of solute therefore the
dissolving equals the crystallization. Unsaturated is when the solution contains less than the ... Show
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The second step was to place the test tube into the hot water and wait for it to dissolve. When it
dissolved, we took it out and placed on a rack to cool it. While the first test tube was in the water we
completed the other 2 test tubes. One by adding 2.5–3g sodium thiosulphate pentahydrate into a test
tube with 1ml of distilled water and stirring until all that would dissolve did and then let it settle.
The other we added 3ml of water to 0.2–0.3g of sodium thiosulphate pentahydrate and stirred until
dissolved then let settle. When all three test tubes were at room temperature we added a crystal of
sodium thiosulphate pentahydrate and observed.
Observations:
Test Tube A– The test tube was hot when it came out of the hot water. It cooled to room
temperature. When we added a crystal of sodium thiosulphate pentahydrate the test tube heated up
slightly and the crystal completely dissolved.
Test Tube B– The test tube settled and came to room temperature. We added a crystal of sodium
thiosulphate pentahydrate, there was no change in temperature and the crystal didn't dissolve.
Test Tube C– The test tube settled and came to room temperature. We added a crystal of sodium
thiosulphate pentahydrate and it dissolved slightly. The test tube became slightly colder.
Data

Iodine Clock Reaction
Kinetics of the Harcourt–Essen Reaction Name: Manpreet Kaur Candidate Number: 7123 AS and
A2 Aims: AS AIMS: 1. Investigate the effect of temperature on the rate of reaction. For this aim 3
sets of results will be obtained by timing how long it takes for the colour change to occur in
different temperatures determined by the use of an electric water bath. With these results, the effect
of temperature on the rate of reaction will be investigated. 2. Determine the activation enthalpy with
and without the catalyst ammonium molybdate(VI) and with different protic acids and use this to
compare the effectiveness. To find out which catalyst is most effective, this aim will be carried out
... Show more content on Helpwriting.net ...
Potassium permanganate is an inorganic compound which is a salt because it has k+ and MnO4–
ions. The oxidizing ability of this compound is very strong and it dissolves in water to produce very
dark purple solution. Potassium permanganate was formerly known as Condy's crystals because the
solution in water would evaporate to give prismatic crystals of a purple/black colour that glistened.
How the Rate of Reaction Varies: Temperature: According to the collision theory, every reaction has
a minimum energy requirement for the molecules to begin reacting. Activation energy is the
minimum energy required for the reaction to begin, the energy is required to break bonds and form
new ones so that products can form. If two molecules collide with energy less than the activation
energy then the molecules will not break any bond, which means no new bonds can form and
therefore no reaction has taken place. Temperature affects the activation energy because by heating
the reaction, molecules gain kinetic energy thus lowering the activation energy and therefore the
reaction can take place faster because the kinetic theory states that molecules move faster. Faster
moving molecules are more likely to collide with more energy than the activation energy and
therefore thus the reaction takes place faster. Activation energy holds great importance

Rates Of Reaction Investigation Report
Rates of Reaction – Sodium Thiosulphate and Hydrochloric acid
In this piece of coursework, I will study how concentration affects the rate of reaction. I will do so
by timing the reaction of Sodium
Thiosulphate with an acid. In this coursework, I will include background knowledge, prediction,
safety, results, calculations, graphs, an analysis, conclusion and an evaluation. In my evaluation I
will comment on how reliable my results were and how I could have improved my coursework in
any possible way.
The definition of rate of reaction is 'The speed at which a chemical reaction takes place'. The factors
that affect the rate of reaction are: · Use of a catalyst
· Temperature
· Surface area
· Concentration
I will be investigating ... Show more content on Helpwriting.net ...
· Bags or any other obstructions should be removed.
I have done a preliminary experiment to help me decide the range of concentrations to use and how
much of a difference in concentration to leave between each one. My preliminary results also show
that 5cm3 is a low enough concentration to begin with. My knowledge tells me that
5cm3 will take longer to react because there are less sodium particles that react with the acid. My
experiment is time based and I will not have enough time to go lower. I took 10 concentrations in
the preliminary test already, and this should show enough of a trend already, so there is no need to
do an even lower concentration, as it would not help my experiment in any way.
Apparatus:
· 100ml conical flask
· Stopwatch
· Thermometer
· Different size measuring cylinders(5ml, 10ml, 50ml)
· Piece of paper.
· Blue or black pen
· Hydrochloric acid

· Sodium Thiosulphate solution
· Water
· Beakers
To keep this a fair test I have made sure that the acid used is the same amount every time. Also the
size of the cross on the piece of paper is the same. The temperature is also the same because the
results could be anomalous if tested in different conditions. Same beakers will not be used for
different chemicals. This can cause reactions in the beakers and will lead to inaccuracies.
GRAPH
My results clearly show that as the concentration decreases, the time increases in the experiment.
This links in with the

The Physics Of Chemical Kinetics
Investigations into the mechanics of chemical kinetics can reveal invaluable information relating to
the rates of reaction. There are numerable applications of reaction rates, knowledge in this area is
pivotal for industrial, commercial and research sectors. Thus, allowing them the ability to
manipulate a variety of factors of chemical reactions with the use of reaction rates. In the scope of
the kinetics of clock reactions, there is a range of information that can be obtained about reaction
rates (Shakhashiri, 1992).
A clock reaction is characterised by an abrupt colour change following an established time lag
(Lente et al, 2007). The induction period in a clock reaction is a result of low concentrations of the
clock chemical (i.e. the chemical that enables the final reaction). The induction period ends after the
total consumption of a limiting reagent, which initiates a short increase in the rate of product
formation, resulting in a visible colour change (Schmitz, 2010)(Lente et al, 2007). The reaction rate
of clock reactions is subject to factors including temperature, concentration, catalysis and inhibition.
These factors can be manipulated, thus changing the length of the induction period in a 'clock–like'
manner (Shakhashiri, 1992).
Changes in the rate of reaction can be described in terms of chemical equilibrium. "Chemical
equilibrium is a state in which the forward and reverse reactions take place at the same rate"
(Wilbraham et al, 2002). The relative

Investigating the Kinetics of the Reaction Between Iodide...
PLANNING
Investigating the Kinetics of the reaction between Iodide ions and Peroxodisulphate (VI) ions
By the use of an Iodine clock reaction I hope to obtain the length of time taken for Iodine ions (in
potassium iodide) to react fully with Peroxodisulphate ions (in potassium Peroxodisulphate). I will
do three sets of experiments changing first the concentration of iodide ions, then the concentration
of Peroxodisulphate ions and finally the temperature of the solution in which the reaction is taking
place. From these results, I hope to draw conclusions as to the effects of these changes to the
environment of the reaction on the rate and also determine the order of the reaction and the
activation enthalpy.
Background information ... Show more content on Helpwriting.net ...
In terms of log to the base 10 this is:
log k = log A –Ea/ 2.303 RT
Reaction between Iodine ions and peroxodisulphate ions
S2O82–(aq) + 2I–(aq)  2SO42–(aq) + I2(aq)
In order to make the reaction clearer, during my experiment I will add starch and a small known
amount of sodium thiosulphate (to act as a queching agent). The thiosulphate ions turn iodine back
to iodine ions:
2S2O32–(aq) + I2(aq)  S4O62–(aq) + 2I–(aq)
Which means that no starch–iodine colour will appear until all the thiosulphate has been used up.
The amount of time taken for this occur (and the reaction to suddenly turn blue) is the same amount
of time for the reaction to produce the equvilant amount of Iodine.
Apparatus
(For making up solutions) weighing boats scales Beaker (150cm3)
3 Volumetric flasks (250cm3)

Distilled water
Glass rod
(for concentraion and temperature change experiments)
4 thermometers (0–110ºC)
A large number of boiling tubes (roughly 50 depending on repeats)
5 Burettes with funnels for filling
5 Clamp stands (for burrettes)
Stopwatch
(for temperature change only)
Two large beakers (400cm3)
Chemicals
Freshly made starch solution
Pottasium Iodide (made to solution with conc. 1.00 mol dm–3)
Pottasium peroxodisulphate (made to solution with conc.

Reaction Rate Of Clock Reactions
Introduction:
Investigations into the mechanics of chemical kinetics can reveal invaluable information relating to
the rates of reaction. There are numerable applications of reaction rates, knowledge in this area is
pivotal for industrial, commercial and research sectors. Thus, allowing them the ability to
manipulate a variety of factors of chemical reactions with the use of reaction rates. In the scope of
the kinetics of clock reactions, there is a range of information that can be obtained about reaction
rates (Shakhashiri, 1992).
A clock reaction is characterised by an abrupt colour change following an established time lag
(Lente et al, 2007). The induction period in a clock reaction is a result of low concentrations of the
clock chemical (i.e. the chemical that enables the final reaction). The induction period ends after the
total consumption of a limiting reagent, which initiates a short increase in the rate of product
formation, resulting in a visible colour change (Schmitz, 2010)(Lente et al, 2007). The reaction rate
of clock reactions is subject to factors including temperature, concentration, catalysis and inhibition.
These factors can be manipulated, thus changing the length of the induction period in a 'clock–like'
manner (Shakhashiri, 1992).
Changes in the rate of reaction can be described in terms of chemical equilibrium. "Chemical
equilibrium is a state in which the forward and reverse reactions take place at the same rate"
(Wilbraham et al, 2002). The

Rate of Reaction of Dilute Hydrochloric Acid and Sodium...
Rate of Reaction of Dilute Hydrochloric Acid and Sodium Thiosulphate
To investigate the change in rate of reaction between DILUTE HYDROCHLORIC
ACID and SODIUM THIOSULPHATE as the concentration varies.
PLAN
A chemical reaction takes place over a specific period of time i.e. which is the time for the reactants
to be formed into the products. If the reactants take a relatively short time to form the products, the
reaction is known as a FAST one. The RATE of that particular reaction is high. On the other hand, a
reaction which takes a longer time is known as a SLOW reaction, and as a result is known to have a
LOW rate of reaction.
There are several factors which alter can alter the speed/rate of a reaction. These are: ... Show more
content on Helpwriting.net ...
Constant: As no solid is involved in our experiment, the particle size theory doesn't matter.
LIGHT– Some chemical reactions are speeded up with light, and not only with heat. For example,
silver is formed from silver salts when a photographic film is exposed to light. On the other hand,
green plants absorb sunlight for photosynthesis, and the more that is absorbed, the higher the rate of
reaction.
Constant: Light is irrelevant to our experiment, so there need not be any control over it.
PRESSURE– Pressure applies only to reactions between gases, and as the pressure increases, so
does the speed of the reaction. The reason behind this is that increasing the pressure pushes the gas
molecules closer towards each other, and so increasing the chances of the gas particles colliding,
causing the reaction to take place at a faster rate. Constant: Pressure is inappropriate to our
experiment as no gases are involved, rather liquids.
In this investigation, we shall be investigating the effect of changes in concentration on the rate of
reaction, and the two chemicals which shall be used will be Sodium Thiosulphate and Hydrochloric
Acid.
Another point to make is that in order to keep the experiment fair, the 'cross' must be kept the same.

The easiest way to do this is to use the same cross for the entire experiment, or else the results
would go unwittingly wrong. A thicker cross on a different paper in the same

The Effect Of Reactant Concentration On Reaction Rate
Effect of Reactant Concentration on Reaction Rate
16/01/2017
Aim:
To investigate the effect of the concentration of Sodium Thiosulfate and Hydrochloric Acid and to
determine the rate of the reaction. Introduction:
Different reactant have different rate on reaction. Some may occur in a sudden; some can take hours
to react. This experiment is to investigate how the reactant concentrations have an effect on the
reaction rate.
The reaction equation of Sodium Thiosulfate and Hydrochloric Acid:
2HCl(aq) + Na2S2O3(aq) 2NaCl(aq) + SO2(g) + S(s) + H2O(l)
(GCSE Chemistry, 2017)
Chemical reactions happens when two chemical bond together and create other chemicals. The
molecules or atoms of two chemicals came close to

Determination of a Rate Equation Essay
Determination of a Rate Equation
Rate equation has the form rate = k [A]x[B]y which shows how the rate of a chemical reaction
depends on the concentration of the reactants
(A&B) and the rate constant k. The rate equation normally indicates what species are involved in the
rate–determining step and how many species are involved.
A rate equation is used to describe how the concentration of a product increases or the concentration
of the reactants decreases with time, the equation also indicates how the concentration of one or
more reactants directly affects the rate. Occasionally it can even be the concentration of a product
that affects the rate. In general the rate equation for the reaction: A + B C + D
Is found by experiment to ... Show more content on Helpwriting.net ...
The equation is:
2HCl(aq) = Na2S2O3(aq) 2NaCl(aq) + S(s) + SO2 (g) = H2O(l)
APPARATUS
=========
· Conical flask.
· Beaker.
· Pipette.
· Burette.
· Clamp stand.
· Grippers.
· Funnel.
· Stop watch.
· Labels.
· Marker pen.
· White paper.
· Goggles.
SOLUTIONS
=========

· 0.2 mol dm–3 of sodium thiosulphate.
· 2.0 mol dm–3 of hydrochloric acid.
· Distilled water.
DILUTION TABLES
===============
2.0 mol dm–3 of hydrochloric acid.
––––––––––––––––––––––––––––––––––––––––––––––––––––––––
Concentration of HCl Volume of HCl Volume of water (Mol dm–3) (cm3) (cm3)
2.0 10.0 0.0 1.0 5.0 5.0 0.5 2.5 7.5 0.25 1.75 8.25 0.0 0.0 10.0
––––––––––––––––––––––––––––––––––––––––––––––––––––––––
0.2 mol dm–3 of sodium thiosulphate.
Concentration of Na2S2O3 Volume of Na2S2O3 Volume of water (Mol dm–3) (cm3) (cm3)
0.2 50.0 0.0 0.1 25.0 25.0 0.05 12.5 37.5 0.025 6.25 43.75 0.0 0 50.0
METHOD 1
========
· Firstly set

Chemical Reactions And The Chemical Reaction
Introduction
Chemistry is a branch of science commonly defined as "the study of the structure, properties, and
reactions of the chemical elements and the compounds they form" (The American Heritage Science
Dictionary, 2002). This definition is very general and covers a range of study areas, including those
that are an asset to society. Chemical reactions are studied by many chemists as they common
occurrences in everyday life (Stewart, 2014). Without chemical reactions people would be unable to
perform simple tasks that are essential for quality of life and even life itself, such as cooking,
lighting a match and breathing (Helmenstine, 2015). A chemical reaction occurs when a chemical
change takes place, producing new substances. However, all chemical reactions are different and
vary greatly in the time it takes for them to occur (Chem4kids.com, 2015).
A Reaction rate is the speed it takes for a chemical reaction to occur. That is, how fast a reactant is
used up or a product is formed (BBC, 2014). Rates of reaction are essential in important tasks such
are medicine administration and it is therefore crucial for scientists to understand how they work
and what affects them (Lofts, 2012). The mechanics of reaction rates is based around the theory of
collision, proposed by Max Trautz and William Lewis in the early 1900's. The theory suggests that
reactant particles must collide for a chemical reaction to occur, the more collisions that occur, the
faster the reaction rate will

An experiment to investigate the effect of changing the...
An experiment to investigate the effect of changing the concentration of hydrochloric acid on the
rate of reaction with sodium thiosulpahte.
Aim
I am trying to find out how the concentration of hydrochloric acid affects the reaction time with
sodium thiosulpahte.
If a clear solution of sodium thiosulphate is mixed with hydrochloric acid then a reaction will occur
where a creamy–yellow precipitate of sulphur is produced.
H20
Text Box: + Text Box: + Text Box: + Na2S203 2HCL
Text Box: + 2NaCl SO2 S
Reactants Products
The sulphur takes a while to form and starts to turn the water cloudy after a short time. You cannot
tell when the reaction has stopped so a cross drawn on a piece of paper in pencil can be ... Show
more content on Helpwriting.net ...
They all increase the number of collisions.
Fair testing
* To make this a fair test I will only change one variable.
* Each experiment will be done three times so an average can be found.
* The same equipment will be used in each experiment.
Method
· Measure out 50ml of thiosulphate and add it to the conical flask.

· Draw a cross on a piece of paper and place the conical flask on it.
· Measure out 10ml of acid and add it to the conical flask and start timing.
· Look into the top of the conical flask and when the cross can no longer be seen stop the stop
watch.
· Do the experiment again but measure out 8ml of hydrochloric acid. Then add 2ml of distilled
water. The ratio for each experiment will therefore be 10:0, 8:2, 6:4, 4:6 and of acid to water
Conclusion
I conclude that whilst carrying out this investigation I found out that the more acid was in the
solution the cross on the paper disappeared quicker. This shows that the more concentrated the acid
is then the quicker the reaction time. My research about the collision theory was correct and the
more concentrated the solution is then the number of collisions will be increased. If the numbers of
collisions are increased then the reaction time will also be increased.
My prediction 'that the less concentrated the acid is then the longer it will take for the sodium
thiosulphate to react with the acid' is correct because experiment number 5

Experiment 5 Redox Titratio
EXPERIMENT 5 REDOX TITRATION: TITRATION USING SODIUM THIOSULPHATE
Objectives 1. 2. To prepare a standard solution of potassium iodate for use to determine the
concentration of sodium thiosulphate solution accurately. To acquire the proper techniques of
carrying out a titration.
Introduction Redox titrations using sodium thiosulphate as a reducing agent is known as iodometric
titration since it is used specifically to titrate iodine. The reaction involved is: I2 + 2Na2S2O3 I2 +
2S2O322NaI + Na2S4O6 2I– + S4O62–
In this equation I2 has been reduced to I– :2S2O32I2 + 2e S4O62– + 2e 2I–
The iodine/thiosulphate titration is a general method for determining the concentration of an
oxidising agent solution. A known volume of an oxidising ... Show more content on Helpwriting.net
...
Add 25 mL of distilled water into the beaker and stir with a glass rod to dissolve all the potassium
iodate. Pour the potassium iodate solution through a filter funnel into a 250 mL volumetric flask.
Rinse the beaker with distilled water and pour this water into the volumetric flask. Add in more
distilled water to the volumetric flask up to the mark on the neck of the flask. Put the stopper in
place and shake the flask until you get a homogenous solution. The standard solution is now ready
for use in part B.
4.
B.
Standardisation of 0.1 M Sodium Thiosulphate Solution (To be done
individually) 1. Rinse and fill a clean burette with 0.1 M sodium thiosulphate solution that is to be
standardised. Make sure that there are no air bubbles in your burette. Record the initial reading of
your burette. (Note: You should read your burette at eye level. Accuracy of reading the burette
reading should be within the range of + 0.05 mL). Pipette 25.0 mL of the standard potassium iodate
solution that has been prepared in part A into a 250 mL conical flask. Weigh approximately 1 g of
potassium iodide crystals and add it into the solution in the conical flask. Then add in 10.0 mL of
1.0 M sulphuric acid solution and swirl the conical flask until all the KI has dissolved. 6. (i) Titrate

immediately the released iodine with the sodium thiosulphate solution while swirling the conical
flask until a light yellow solution is obtained. (ii) Dilute this solution with

Section 1 Harcourt-Essen Reaction
A2 Chemistry Coursework Section 1 Aims: I aim to find out the order of reaction with respect to
[H2O2] and [2I–]. I aim to find out the activation enthalpy of the reaction by finding the rate of
reaction at different temperatures using the Arrhenius Equation. The experiment will go as follows:
Into a conical flask put 15cm3 of distilled water and add 2cm3 of [X]moldm–3 potassium iodide
(KI) solution and 1cm3 of 2moldm–3 sulphuric acid. Then add to this 2.5cm3 of 5vol (0.42moldm–
3) hydrogen peroxide (H2O2). For the second part of my investigation, the KI solution will remain a
constant 0.3moldm–3 and the H2O2 solution will vary. H2O2 + 2I– + 2H+ –> 2H2O + I2 Methods
to find the rate: 1 – Use a colorimeter to monitor the change ... Show more content on
Helpwriting.net ...
Transmittance can be expressed as the ratio of the intensity of the transmitted light (It) and the initial
intensity of the light beam (Io), as expressed by the formula: reference 4 T = It /Io Experimental
Methods: Making up the solutions: The potassium iodide solution will be made up by first
calculating the amount (in moles) of KI needed from the equation: concentration = amount/volume
as I know the desired concentration(s) and how large a volume I want to make up. Then I can
calculate how exactly how much solid KI (in grams) is needed for that concentration by using the
equation: amount = mass/Mr – given the Mr of KI is 166.0028. Then to actually make up the
solution, I will first brush the balance, place a plastic weighing container on it, and then tare the
balance. I will then proceed to accurately weigh out the required mass of KI with a clean spatula.
The hydrogen peroxide solution will be diluted from 20vol to [X]vol by using 20/[X] the volume of
20vol H2O2 in distilled water. Methods: Potassium iodide solution: 1. Using the equations; amount
= mass/Mr and concentration = amount/volume, I calculated the correct mass of KI needed to make
up the required concentrations of KI solution (0.05 through to 0.3moldm–3). I used the complete
values throughout all the equations, and then rounded my final volume to an appropriate decimal
place relative to the precision of the scientific balance I will use to make up the solution. 2. Solid KI
(mass m) was weighed

The Effect Of Sodium Thiosulphate On Reaction Rate
Title:
The effect of Hydrochloric Acid volume with Sodium Thiosulphate on the reaction rate.
Introduction:
Research Question: How does changing the volume of Hydrochloric Acid on Sodium Thiosulphate
effect the time taken for the 'X' Mark to dissapear?
The rate of a chemical reaction is the time required for a given quantity of reactant to be changed to
product. The unit of time may be seconds, minutes, hours, days or years. For a chemical reaction to
occur it needs to have a collision, and it is affected by several factors, such as temperature increases
in general increase the rate of reaction, for the example 2O°C rise in temperature doubles the
reaction rate. Catalysts affect the rate by using or allowing a different pathway for the reaction ...
This occur because the increase of volume of HCl will increase the rate of reaction between
Hydrochloric acid and sodium Thiosulphate particles.
The scientific result for this experimet is the results from preliminary experiments support the
prediction made.From the results you can see that there is a directly proportional relationship
between the concentration and the rate of reaction. Ifyou increase the concentration then the rate of
reaction will also increase. The volume of a solution will effect the rate of reaction because the rate
of reaction depends on how much the molecules of reacting substance will collide, more volume of
HCL make the reaction of Sodium Thiosulphate and HCL to react faster.
This experiment is testing how the rate of reaction is affected when volume is changed. The theory
is said that increasing the volume can increase the rate of reaction by increasing the rate of
molecular collisions. The phenomenon behind all of this is the collision theory and how it plays a
big role in this investigation. The higher the volume of a solution the less time/faster it will take for
the system to turn into equilibrium, and if concentration is decreased, time taken for the solution to
go cloudy

Chemistry Lab Report for Vitamin C Estimation by...
Vitamin c Estimation by back(idiometric) titration Mahindra (UWC of India) Chemistry lab report
for back titration Name: Ashenafi Asfaw Beyene
Back (Indirect) Titration
Vitamin C estimation by Back Titration
Table1: The amount of volume (in cm3) and concentration (in M) of KI, KIO3, and H2SO4 which
were used in the experiment of Vit C estimation by back titration.
VKI added to the solution/cm3 Concentration of KI added to the solution/M Volume of KIO3 added
to the flasks ±0.08/cm3 Volume of H2SO4 added to the solution±0.08/ cm3 Concentration of
H2SO4 added to the solution/M
15.0 ... Show more content on Helpwriting.net ...
This is equal to the mole of ascorbic acid in 10cm3.
So the total moles of ascorbic acid in 100cm3 solution = 1.42X 10–3 mol±0.7mol
Mass of ascorbic acid = 176 *(1.42X 10–3 mol) = 0.249 g ±1g
Mass of ascorbic acid=0.249±1/g
Calculation for percentage yield in ascorbic acid
Theoretical mass for ascorbic acid is given as
Each tablet contains 0.10mg there for 3 tablets contains 0.30g
%yield=(experimental mass/theoretical mass) X100 %=( 0.249g/0.30g)x100%=83%
Therefore %yield in ascorbic acid is 83%
Error Propagation in mole of ascorbic acid
%error in mole of ascorbic acid for part

Reaction Temperature Lab
Determining the Effect of Temperature on a Chemical Reaction In the experiment, my partner and I
will be conducting small tests multiple times to determine what effect temperature of a solution can
have of the speed of a reaction. Heating up sodium thiosulphate in a water bath will alter the
temperature of the solution. The sodium thiosulphate will then be added to room temperature
hydrochloric acid, and using a stopwatch, we will record how long each reaction takes. My partner
and I have decided to do the 90 degrees, 50 degrees, room temperature and ice bath. We have also
decided to conduct each experiment 3 times and find the average of the three different times per
temperature. Aim: To investigate how the temperature of a solution affects ... Show more content on
Helpwriting.net ...
– Wear rubber gloves. – Wear lab coats/jackets. – Wear safety goggles. – Avoid contact with skin. –
Do not intentionally inhale. Sodium thiosulphate – Irritation of eyes and/or skin. – Irritation of the
respiratory and/or digestive tract if ingest/inhaled. – Wear rubber gloves. – Wear lab coats/jackets. –
Wear safety goggles. – Avoid contact with skin. – Do not intentionally inhale. Hot water – Is
capable of burning. – Usage of rubber mittens (when handling the 90°C sodium thiosulphate). Risk
assessment: Method: 1. Using the markers, draw a dot in the centre of the white tile. 2. Using the
5ml–measuring cylinder, pour 5ml of hydrochloric acid into it. Set–aside for now. 3. Pour 40ml of
sodium thiosulphate into the 50ml–measuring cylinder then transfer the sodium thiosulphate into the
conical flask. Place conical flask right above the dot on the

The Effect Of Calcium On The Reaction Of Hydrogen Peroxide
Introduction: The aim of this experiment was to determine the effect of varying concentrations of
potassium iodide on its reaction with hydrogen peroxide. H2O2(aq) + 2H+(aq) + 2I–(aq) → 2H2O
+ I2 In this experiment, the hydrogen peroxide reacts with iodide ions to produce iodine. The iodine
can be detected by its colour forming a blue–black solution. The detection of the iodine can be
enhanced by the addition of starch solution. The sodium thiosulphate will react with the iodine ions
and when the all the sodium thiosulphate has reacted, then the remaining iodine ions will suddenly
appear to form the coloured solution due to the addition of starch. I2(aq) + 2S2O32– (aq) → 2I–(aq)
+ S4O62– (aq) The concentrations of each of the reactants ... Show more content on Helpwriting.net
...
The rate of reaction is dependent on the slowest step which is called the 'rate determining step'. The
nature of the slow step is not obvious from the balanced equation. The order of reactions with
respect to each reactant in the RDS is the same as the number of moles of that chemical in the RDS
A series of experiments were carried out in which the concentration of iodide ions is varied while
keeping the concentrations of all the other solutions the same. In each experiment, the time taken for
the colour change is recorded. The results obtained are used to determine the rate of reaction. The
rate of reaction can be represented as (1/time) and the concentration of the iodide ions can be
represented by the volume of potassium iodide solution used. Materials: Selection of syringes –
5cm3, 10cm3 100 cm3 glass beakers White tile Timer Lab coat Gloves Safety goggles 1 mol l–1
sulphuric acid 0.1 mol l–1 potassium iodide 0.1 mol l–1 hydrogen peroxide 0.005 mol l–1 sodium
thiosulphate 1% starch solution Deionised water Hazards: Because sulphuric acid is both a strong
acid and a powerful dehydrating agent, it must be handled with great care. Both sulfuric acid and
hydrogen peroxide can irritate the skin and eyes as well as the other chemicals. Care: Wear safety
goggles and lab coat Any chemical contact with skin, wash off immediately Procedure: Using

The Hydrogen Peroxide Iodine Clock: Above Rates Of Reaction
The Hydrogen Peroxide Iodine Clock can be used to demonstrate the above rates of reaction that
lead to chemical equilibrium and explore also the impact of concentration of reactants and
temperature on rates. In this experiment, hydrogen peroxide and sulphuric acid are added to a
another solution of potassium iodide, sodium thiosulphate and starch. After a lag, the combined
solution turns a deep blue colour. The reactions occurring are as follows.
(1) 3I–(aq)+H2O2 (aq)+2H+I3–(aq)+2H2O(l) Hydrogen peroxide is an oxidising agent that oxidises
iodide ions to iodine in acidic medium. In other words, the iodide ions are oxidised by the peroxide
to form triiodide ions. (Cldfacility.rutgers.edu, 2017) This is shown by equation (1)
The triiodide ions created in equation (1) are reduced back into iodide ions by the sodium
thiosulphate ions in the solution. This phase of the clock reaction is shown in equation (2) (2) I3–
(aq)+2S2O32–(aq)3I–(aq)+S4O62–(aq) After all the sodium thiosulphate ions have been consumed
in the reaction process, the remaining triiodide ions that were liberated from the sodium thiosulphate
react with the starch in the solution which is shown in equation (3) (Cldfacility.rutgers.edu, 2017)
(3) 2I3–(aq)+starch(aq)starch–I5–complex(aq)+I–(aq) ... Show more content on Helpwriting.net ...
This process is chemically analogous to a titration. As when conducting titrations, one substance is
mixed with another until a critical condition triggers a visible change in the solution, 'the endpoint'
(Shakhashiri, 1992). In a clock reaction two solution are mixed together until the critical condition
triggers the sudden change in colour. This colour change is similar to the end point of a titration, in a
clock reaction usually a rapid change in the concentration of one of the substances is the cause of
the

The Effect of Temperature on the Rate of Reaction Essay
The effect of temperature on rates of reaction
Aim:
The aim of this experiment is to find out if the reaction rate of sodium thiosulphate solution and
hydrochloric acid will be affected by a temperature change.
Prediction:
I predict that as a result of increasing the temperature of the sodium thiosulphate, the rate of reaction
will be faster. Because of the increase in temperature, the particles will gain more kinetic energy.
This will therefore cause them to move faster and produce more successful collisions, causing the
rate to increase.
Plan:
Na S O + 2HCl S + SO + 2NaCl + H O
Before carrying out the experiment, I must first of all begin the preliminary work. This part of the
experiment will enable me to choose an appropriate ... Show more content on Helpwriting.net ...
I will also make sure the apparatus is thoroughly cleaned before repeating the experiment. The only
thing I will be changing for each reaction will be the temperature.
GRAPH
Diluted 5/5 with water
Apparatus:
For the experiment I will use:
* Sodium Thiosulphate solution
* Hydrochloric acid
* Water
* A test tube

* A beaker
* A hot plate
* A thermometer
* A stopwatch
* A glass bottle
* Ice
Preliminary work:
From my preliminary results graph, I could determine how I needed to change the scale and
concentration of my experiment. Using 10cm of sodium thiosulphate, I quickly discovered that at 45
C the reaction was too fast to measure and so for my scale to reach above that, I needed to dilute the
sodium thoisulphate. When I accordingly changed the concentration to 5cm distilled water and 5cm
sodium thoisulphate. I noticed that I would be able to conduct the experiment until 50 C because at
55 C it was only just measurable and this may be a source of error if I wasn't able to record the
results in time.
After analysing the data from my preliminary work, I decided to add in an extra temperature of
below room temperature at 10 C which would produce a more in depth experiment. I also cut out
some temperatures where the time taken for the black cross to be obscured was similar to other
temperatures. For example 35 C where there

Effect Of Reactant Concentration On Reaction Rate . ....
Effect of Reactant Concentration on Reaction Rate
Research Question
What is the effect of reactant concentration on reaction rate?
Aim
To investigate the effect of reactant concentration on reaction rate.
Introduction
This experiment is based on the effect of reactant concentration on reaction rate. "Reactant
concentration is the amount of the chemical and the number of molecules being used and the higher
the amount of reactant the higher the reaction rate is and the lower the amount of the reactant the
lower the reaction rate."(WikiAnswers,2017) Reaction rate is the speed of the reactant. Such as the
reactant Sodium Thiosulfate and Hydrochloric Acid, the higher the concentration the higher the
reaction rate but when water is ... Show more content on Helpwriting.net ...
Draw a black cross in a sheet of paper and place the conical flask with the 25ml Sodium thiosulfate
over the black cross.
Measure 5mL of hydrochloric acid on the 5mL measuring cylinder and place it into the conical flask
that was used earlier.
Pour the 5mL of hydrochloric acid into the conical flask with the Sodium thiosulfate in it and start
the stopwatch as soon as the hydrochloric acid has been added.
Observe how the two solution collide with each other and stop the stopwatch as soon as the black
cross cannot be seen.
Record the time it takes for the black cross to disappear and record it on a results table.
Dispose the two solutions in the conical flask and wash the flask to make sure there 's no extra
solutions left.
Repeat steps 1–7 with a different concentration which is shown in Table 1.0 and repeat it for 3 trials
with HCI, Na2S2O3 and distilled water.
Risk Assessment
Variables
Result

Table 1.0– Volumes of Sodium Thiosoulfate, Hydrochloric Acid and Distilled Water.
There was a lot of anomalies that was taken out of the average because it would make the result
inaccurate. The anomalies were:
In trial 3 1st column– 181.2 Trial 3 2nd column– 303 Trial 1 3rd and 4th

Why Do Chlorine Remains In A Pool
Introduction:
I chose this project because I am a competitive swimmer and I have been swimming for the past ten
and a half years. I wanted to find out how much chlorine remains in a pool each day after
chlorination. I am interested to see how much residual chlorine is left and the range in which there
appears skin irritation and red eyes because I have experienced the red eyes and itchy skin due to
over chlorination.
Chlorine is used in pools in either a gaseous or as sodium or calcium hypochlorite. The chlorine is
added to water to help prevent people from getting sick from disease–producing microorganisms.
The chlorine that is added and reacts with the organic material and metals in the water is the
chlorine demand for the water as it will not be available for any disinfection that keeps people from
getting sick while in the pool. The residual test is ... Show more content on Helpwriting.net ...
The free iodine is than titrated with the sodium thiosulphate solution.
I2 + 2 S2O32– 2 I– + S4O62–
For every two moles of thiosulphate, one mole of iodine is needed so the amount of iodine mole
needed is half the amount of thiosulphate moles that are needed. Starch is used as the indicator for
the end point because the iodine and water is such a faint yellow color that the starch will combine
with any of the iodine that is still present and turn it a blue color and the end point for the titration is
than easier to notice.
I found the amount of amount of residual chlorine using the equation:
Residual chlorine = volume of Na2S2O3 x Concentration of Na2S2O3 x mass of 1 mol Cl– x 1000
Volume of sample pool water
Adverse effects can occur if there is too much residual chlorine in water. The use of chlorine can
possibly cause carcinogenic compounds such as chloroform. There is still an ongoing debate if
chlorine is the best way to disinfect a

Determination of Ffa and Iodine Value
UNIVERSITI MALAYSIA SABAH
SCHOOL OF FOOD SCIENCE & NUTRITION
LABORATORY REPORT
NT20903 FOOD CHEMISTRY AND BIOCHEMISTRY
Determination of free fatty acid(FFA) and iodine value (IV)in oil
LECTURER NAME : MOHD NAZRI BIN ABDUL RAHMAN
LAB SESSION : 3 OCTOBER 2011 (GROUP 4, MONDAY)
Group Member
Title: Determination of free fatty acid (FFA) in oil and determination of iodine value (IV) in oil
Introduction
Acid value or free fatty acid content is an important characteristic commonly used in quality control
of fat and oil. Fats and oils are one of the large variety and important sources in the world. It
contains acidity which is the result of the degree of breakdown of the triacylglycerols by a chemical
reaction known as ... Show more content on Helpwriting.net ...
H H H H H H H H H C C = C C H + Br2 H C C C C H H H H Br Br H
One application of the iodine number is the determination of the amount of unsaturation contained
in fatty acids. This unsaturation is in the form of double bonds which react with iodine compounds.
The higher the iodine number, the more unsaturated fatty acid bonds are present in a fat. In a typical
procedure the acid is treated with an excess of Wij's iodine solution which a solution of iodine
monochloride (ICl) in glacial acetic acid. The iodine concentration is then determined by titration
with sodium thiosulfate. Iodine value is the average unsaturation measurement in fat sample.
Although iodine value is expressed as the weight of iodine added to 100 g of sample, the analytical
procedure used to determine the iodine normally use iodine monochloride in acetic acid solution
(Wijs' reagent) as halogenations agent.
Objective
1) To determine the free fatty acid found in oil.
2) To differentiate between the free fatty acid formed during the hydrolysis process and oxidation
process.
3) To understand the relationship between acid value and free fatty acid

4) To determine the iodine value (IV) in oil
5) To

Sodium Thiosulphate Lab Report
Preparation of Standard Volumetric Solutions
1. 0.1N Sodium thiosulphate solution
Reagents: Sodium thiosulphate crystals, Potassium dichromate (primary standard NIST certified),
Sulphuric acid, Potassium iodide , Starch Solution (1%): Weigh 1g of soluble starch and mix it with
100ml of boiled water.
Procedure
Weigh 25 g of sodium thiosulphate crystals and transfer it in a 1000 ml volumetric flask.
Dissolve it in minimum amount of distilled water and make up the volume to 1000 ml.
Standardization of the prepared Sodium thiosulphate solution as follows:
Weigh 0.125 g of dry Potassium dichromate (K2Cr2O7) and transfer it into an iodine flask. Dissolve
it in minimum amount of distilled water.
Add 10 ml of Sulphuric acid and then 10 ml ... Show more content on Helpwriting.net ...
S. No. Wt of empty dish, W (g) wt of (sample + dish) before drying ,W1 (g) wt of (sample + dish)
after drying ,W2 (g) Moisture % Average
1 73.5172 76.5891 76.2216 11.96%
11.66%
2 77.1345 79.3092 79.0619 11.37%
Result
The percentage of moisture content determined in Chana dal is 11.66% .
6
EXPERIMENT 3
Aim: To determine the fat content in food sample by Soxhlet extraction method.
Introduction
The crude fat content can be conveniently determined in foods by extracting the dried and ground
material with petroleum ether or diethyl ether in Soxhlet extraction apparatus.
Principle
Extraction of the crude fat is carried out either with petroleum ether or diethyl ether in a Soxhlet unit
followed by volatilization of the solvent after extraction and determination of the mass of the
residue.

Apparatus Required
Soxhlet apparatus
Reagents
Diethyl Ether –anhydrous or Petroleum ether (b.p. 60–80°C)

Chemical Oxygen Demand ( B.o )
31. Biological Oxygen Demand ( B.O.D)
Introduction:
Biochemical Oxygen Demand (B.O.D.) is the most important parameter to determine the level of
pollution in lakes and streams, their self–purification capacities, assess the biodegradable organic
load of the wastewaters for designing wastewater management or treatment plants and thereafter to
evaluate their efficiency or finding out the assimilative capacity of a water body. B.O.D. is an
empirical standardized laboratory test defined as the amount of oxygen required for the aerobic
decomposition of the organic matter by micro–organisms into stable inorganic forms at a given
controlled condition of time and temperature in water. The quantity of oxygen required for above ...
The greater the B.O.D., the more rapidly oxygen is depleted in the stream which means less oxygen
is available to higher aquatic forms of life. As a consequence organisms that are more tolerant of
lower dissolved oxygen levels may replace a diversity of more sensitive organisms.
A. Titrimetric method
Principle
The B.O.D. test is based on mainly bio–assay procedure, which measure the dissolved oxygen
consumed by micro–organisms while assimilating and oxidizing the organic matter under aerobic
condition. This test measures the oxygen utilized for the biochemical degradation of organic
material (carbonaceous demand) and oxidation of inorganic material such as sulphides and ferrous
ions during a specified incubation period. It also measures the oxygen used to oxidize reduced forms
of nitrogen (nitrogenous demand) unless their oxidation is prevented by an inhibitor. Temperature
effects are held constant by performing a test at fixed temperature. The methodology of B.O.D. test
is to compute a difference between initial and final D.O. of the samples incubation. Atleast 1.5 L of
sample is required to perform the B.O.D. test. D.O. is estimated by iodometric or Winkler's method
titration. Since the test being a bio–assay procedure, it is necessary to provide standard conditions of
temperature, nutrient supply, pH (6.5–7.5), adequate population of microorganisms and absence of
microbial–growth–inhibiting substances. The low

Rate Of Reaction Between Hydrochloric Acid And Sodium T
Experimental Investigation – Rate of Reaction
Research Topic:
The topic includes the effect of concentration and temperature on the rate of reaction between
hydrochloric acid (HCl) and Sodium Thiosulphate (Hypo solution). There are multiple ways to test
the rate of reaction between two substances, however the experiment we will be conducting
involves placing a conical flask directly over a black coloured 'x' and recording the time it takes for
the 'x' to become invisible after the two solutions react with each other. This is simple and direct as
multiple tests can be undertaken at different concentration levels and multiple temperatures.
Sodium Thiosulphate and Hydrochloric Acid Reaction
Na2S2O3 (aqueous) + 2HCl (aqueous) → 2NaCl ... Show more content on Helpwriting.net ...
Aim:
The overall aim of this experimental investigation is to further research and investigate the factors
of temperature and concentration and how these two elements can alter or change the speed or rate
of a reaction. The aim will be investigated thoroughly, with multiple experiments being conducted
to ultimately fulfil this aim, with as much detail and data as possible so an in–depth conclusion can
be delivered.
Hypothesis:
It is hypothesised that when the temperature at which the chemical reaction takes place is increased,
the speed of the reaction will also increase, whereas when the temperature at which the chemical
reaction takes place is decreased, the speed of the reaction will decrease. This hypothesis correlates
to the investigation because when the Hydrochloric acid is at a higher temperature, the solution that
is mixed with it, in this case Sodium Thiosulphate, the rate at which the reaction occurs will be
much faster. Whereas, when the temperature of the Hydrochloric acid is decreased, the Sodium
Thiosulphate solution that will be mixed in will result in the rate at which the reaction occurs being
much slower. It is also hypothesised that when the concentration of a solution in a chemical reaction
is increased, the speed of the reaction increases. Whereas, on the other hand, when the concentration
of the solution in the chemical reaction is decreased, the speed at which the reaction occurs will be
far slower. This

The Rate Law for Chemical Reaction Among Hydrogen...
The Rate Law for Chemical Reaction Among Hydrogen Peroxide, Iodide, and Acid
To determine the rate law for a chemical reaction among hydrogen peroxide, iodide and acid,
specifically by observing how changing each of the concentrations Experiment 3 Chemical Kinetics
Objectives
1. To determine the rate law for a chemical reaction among hydrogen peroxide, iodide and acid,
specifically by observing how changing each of the concentrations of H2O2, and H+ affects the rate
of reaction.
2. To observe the effects of temperature and catalyst on the rate of reaction.
Introduction
Generally, two important questions may be asked about a chemical reaction: (1)How far do the
reactants interact to yield products, and (2) ... Show more content on Helpwriting.net ...
7. 10 cm3 of 2.0 M sulphuric acid was measured with a 10 cm3 clean measuring cylinder. It was
pour into the conical flask.
8. 1 g of solid KI (record the exact mass) and 3 drops of ammonium molybdate catalyst were added
into the conical flask.
9. The solution mixture was stirred until the KI dissolves.
10. The reaction mixture was titrated in the conical flask with the sodium thiosulphate solution until
it just turns pale yellow.
11. 3 drops of freshly prepared starch solution were added to the conical flask.
12. The titration was continued until it just changes from dark blue to colorless. The final reading
was recorded in Table 1. It was a first trial titration to estimate the volume of the sodium
thiosulphate solution required. The volume of the sodium thiosulphate solution added in titration
was calculated.

13. The given sodium thiosulphate solution was added to the burette through a filter funnel if the
volume remained was not enough to carry out another titration.
14. Steps 6–13 were repeated to obtain 2 sets of consistent results.
However, sodium thiosulphate solution was stopped draining at about 3 cm3 less than the estimated
value. Then the sodium thiosulphate solution was added drop by drop until the reaction mixture in
conical flask just changes from dark blue to colorless.
Part II) Reaction Rate Measurements
Six reaction mixtures will provide the information necessary to
determine

The Factors Controlling the Rate of the Sodium...
The Factors Controlling the Rate of the Sodium Thiosulphate and Acid Reaction
Planning
I am investigating the factors controlling the rate of thiosulphate / acid reaction. The reaction that
will be taking place will follow the rate at which sulphur is formed in the reaction of sodium
thiosulphate with dilute hydrochloric acid. In the experiment the sulphur will appear as an extremely
fine precipitate. This will slowly be followed by a milky appearance in the reaction mixture in the
conical flask. As the amount of the sulphur in the mixture increases, the precipitate will become
milkier. Gradually the liquid will become more and more opaque. To investigate the rate of the
reaction, we will use ... Show more content on Helpwriting.net ...
It is a reduction to one quarter of the rate at the beginning.
[IMAGE]
No. of particles
with given KE
[IMAGE]
[IMAGE][IMAGE] Hotter substance
[IMAGE][IMAGE] Higher temperature
[IMAGE][IMAGE] Activation energy
[IMAGE][IMAGE] Energy Min K.E for reaction
No of molecules with K.E> The minimum energy needed to react is directly proportional to the
shaded area
By looking at the graph one can say that by looking at the shape of the curve the area surely must
increase with increased temperature.

The Preliminary Experiment
The aim of the preliminary experiment was to find out suitable concentrations of thiosulphate one
should put in to the reaction. I did not want to end up doing the experiment without knowing how
long it will take and which concentrations would be suitable.
Method
Ø Apparatus: Conical flask, burette, stopwatch, a cross on a piece of paper, a thermometer and
safety glasses.
Ø Safety procedures: One must wear safety glasses at all times because there are dangerous
chemicals in the experiment. One should also stand up when doing the experiment so if the flask
falls off the bench you do not get hurt.
Ø Firstly I chose three concentration levels for the experiment. These are shown in the table below.
Volume of thiosulphate
(cm )
Volume of H2O
(cm )
Volume of HCL (cm )
50
0

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