RATE OF REACTION (FAST & SLOW REACTION, AVERAGE RATE OF REACTION AND INSTATAN...MISS ESTHER
CHAPTER 7 RATE OF REACTION
CHEMISTRY FORM 4 KSSM
1. Identify fast and slow reaction
2. Define rate of reaction
3. Determine the observable and measurable changes to calculate rate of reaction
4. Average rate of reaction and instataneous rate of reaction
6.9 PREPARATION OF SALTS
CHEMISTRY KSSM FORM 4
REACTION BETWEEN ACID + ALKALI
REACTION BETWEEN ACID + METAL OXIDE
REACTION BETWEEN ACID + REACTIVE METAL
REACTION BETWEEN ACID + METAL CARBONATE
PURIFICATION OF IMPURE SALTS USINGRECRYSTALLISATION METHOD
DOUBLE DECOMPOSITION REACTION TO PRODUCE INSOLUBLE SALT
INVESTIGATE THE PROPERTIES OF IONIC BOND AND COVALENT BOND THROUGH AN EXPERIMENTMISS ESTHER
CHEMISTRY FORM 4 KSSM
CHAPTER 5 : CHEMICAL BONDS (IONIC BOND AND COVALENT BOND)
EXPERIMENT 5.1 TO INVESTIGATE THE PROPERTIES OF IONIC BOND AND COVALENT BOND THROUGH EXPERIMENT
RATE OF REACTION (FAST & SLOW REACTION, AVERAGE RATE OF REACTION AND INSTATAN...MISS ESTHER
CHAPTER 7 RATE OF REACTION
CHEMISTRY FORM 4 KSSM
1. Identify fast and slow reaction
2. Define rate of reaction
3. Determine the observable and measurable changes to calculate rate of reaction
4. Average rate of reaction and instataneous rate of reaction
6.9 PREPARATION OF SALTS
CHEMISTRY KSSM FORM 4
REACTION BETWEEN ACID + ALKALI
REACTION BETWEEN ACID + METAL OXIDE
REACTION BETWEEN ACID + REACTIVE METAL
REACTION BETWEEN ACID + METAL CARBONATE
PURIFICATION OF IMPURE SALTS USINGRECRYSTALLISATION METHOD
DOUBLE DECOMPOSITION REACTION TO PRODUCE INSOLUBLE SALT
INVESTIGATE THE PROPERTIES OF IONIC BOND AND COVALENT BOND THROUGH AN EXPERIMENTMISS ESTHER
CHEMISTRY FORM 4 KSSM
CHAPTER 5 : CHEMICAL BONDS (IONIC BOND AND COVALENT BOND)
EXPERIMENT 5.1 TO INVESTIGATE THE PROPERTIES OF IONIC BOND AND COVALENT BOND THROUGH EXPERIMENT
Ferric Chloride is a dark colour crystal with the oxidation state of iron is +3. It is also called Iron (III) chloride or Molysite. It is an iron coordination entity which functions as an astringent and Lewis acid. The chemical formula of Ferric Chloride is FeCl3.
Investigatory project chemistry on to study the digestion of starch by salivary amylase and effect of temperature and pH on it and
1)To study digestion of starch by saliva.
2)To study the effect of temperature on the digestion of
starch by saliva.
3)To study the effect of pH on the salivary digestion of
starch.
Ferric Chloride is a dark colour crystal with the oxidation state of iron is +3. It is also called Iron (III) chloride or Molysite. It is an iron coordination entity which functions as an astringent and Lewis acid. The chemical formula of Ferric Chloride is FeCl3.
Investigatory project chemistry on to study the digestion of starch by salivary amylase and effect of temperature and pH on it and
1)To study digestion of starch by saliva.
2)To study the effect of temperature on the digestion of
starch by saliva.
3)To study the effect of pH on the salivary digestion of
starch.
Chem 162 Lab 3: Gas Laws Part I & II- Sample Data for the class
1) Sample Data Group 1:
Part I
Part II
Volume (ml)
Pressure (kPa)
Temperature (°C)
Pressure (kPa)
103.0
60
70.8
113.5
88.0
70
66.3
112.6
73.0
85
61.8
111.5
62.0
100
57.1
110.4
44.0
140
51.5
109.0
34.0
180
39.9
105.5
31.0
200
26.4
101.8
10.5
96.7
2) Sample Data Group 2:
Part I
Part II
Volume (ml)
Pressure (Torr)
Temperature (°C)
Pressure (kPa)
32.0
630
57
109.6
29.2
690
52
108.4
27.8
726
48.5
107.4
25.6
790
43.6
106.3
24.2
843
38.1
104.8
22.2
914
33.1
103.5
29.3
102.2
25.4
101.1
22.5
100.1
20
99.4
17.4
98.6
12.8
97.2
9.4
96.7
Bellevue College | Chemistry 162
1
Empirical Gas Laws (Part 3): The Ideal Gas Law
Determination of the Universal Gas Constant, R
In this experiment, you will generate and collect a sample of hydrogen gas over water by the
reaction of magnesium with hydrochloric acid.
Using the Ideal Gas Law (PV=nRT) you will find values for the pressure (P), volume (V),
number of moles of the gas (n), and the temperature (T) in order to determine the gas constant
(R). Because there will be water vapor present in your sample, you will make a correction to the
measured pressure and then compare your result for R to the literature value.
In this experiment, you will:
Determine a value for the Universal Gas Constant, R. (Part 3 of Empirical Gas Laws)
Safety Precautions
Wear your goggles at all times. Hydrochloric acid is corrosive.
Avoid spills and contact with your skin and clothing. If HCl
comes in contact with your skin, inform your teacher and flush
the acid with large quantities of water.
Note: If you are doing Part 3 to determine the value of the Universal
Gas Constant, R in the same period as Parts 1 and 2, you should get Part 3
started first.
EXPERIMENTAL PROCEDURE (WORK IN PAIRS)
1. Put on goggles. Keep them on during the entire experiment.
2. Obtain a piece of magnesium ribbon that weighs no more than 0.08 grams. Record the mass
obtained (use significant figures!). Record this value in your data table (see report sheets).
Loosely roll it into a ball or coil it.
Encase the magnesium in a piece of copper mesh. Why do you think this might be helpful?
3. Fill the 800-mL beaker with approximately 200-mL of tap water.
4. Fill the 100-mL graduated cylinder with tap water. Using parafilm, a one-
hole stopper, or the palm of your hand, cover the top and invert the cylinder
into the beaker of water. You will end up with an inverted cylinder full of
water. Remove the parafilm or stopper if you used one. Rest the cylinder
on the bottom of the beaker. Try not to introduce any air bubbles in your
inverted cylinder (see Figure 1).
5. Place the magnesium (in its copper cage) into the graduated cylinder. Make
sure the magnesium is captured in the cylinder.
Figure 1: Gas collection in an
inverted cylinder full of water.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
Francesca Gottschalk - How can education support child empowerment.pptxEduSkills OECD
Francesca Gottschalk from the OECD’s Centre for Educational Research and Innovation presents at the Ask an Expert Webinar: How can education support child empowerment?
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
CLASS 11 CBSE B.St Project AIDS TO TRADE - INSURANCE
Exam q and solutions rate of reaction
1. Rates of Reaction
2003
Question 7.
(a) Define rate of a chemical reaction.
(5)
Calcium carbonate (marble chips) reacts with hydrochloric acid according to the following equation.
CaCO3 + 2HCl = CaCl2 + CO2 + H2O
Using simple experiments involving marble chips, CaCO3, and hydrochloric acid, HCl, describe how you could
demonstrate the effects of (i) particle size, (ii) concentration on the rate of a chemical reaction.
(18)
(b) What is a catalyst?
(6)
Catalytic converters are used in cars.
(i) Identify one reaction which is catalysed in the catalytic converter in a car.
State one of the environmental benefits of this process.
(12)
(ii) Name one element used as a catalyst in a catalytic converter.
What type of catalysis is involved in a catalytic converter?
(9)
2003
Question 7
(a)
(i)
(ii
)
(b)
(i)
(ii
)
2004
Define: change in concentration per unit time Accept ‘rate of change of concentration’
Do not accept ‘mass’, ‘volume’, ‘quantity’, ‘amount’ in place of ‘concentration’.
mass of small particles (powder), equal mass of larger particles (granules, lumps) // (3)
added to equal volumes of HCl of same concentration // (3)
note times to complete OR observe vigour of reactions OR smaller particles faster (3)
equal amounts of equal-sized particles (e.g. powder*) of CaCO3 (3)
added to equal volumes of HCl of different concentrations (3)
note times to complete OR observe vigour of reactions OR higher conc. faster (3)
* “Equal-sized” needed for all particles except powder. (Can be got from clear graph)
Catalyst: substance that alters (speeds up) rate of reaction (3)
not used up OR chemically unchanged at the end (3)
reactant(s) (3) product(s) (3) environmental benefit* (6)
allow ‘prevents air pollution’ in all four cases for (3) marks.
carbon monoxide (3) to carbon dioxide (3) benefit - CO toxic (6)
hydrocarbons (3) carbon dioxide & water (3) prevents smog OR reduces greenhouse effect 6)
CO and NO (3) CO2 and nitrogen (3) CO toxic / NO leads to acid rain (6)
nitrogen oxides (3) nitrogen and oxygen (3) NOx (or specified NOx)causes acid rain (6)
Note: reactant and product marks can be got from equations which need not be balanced.
Name: platinum / palladium / rhodium Accept symbols. Do not accept ‘gold’.
ANY ONE: (3)
Type: heterogeneous OR adsorption (6)
(5)
(9)
(9)
(6)
(12)
(9)
Question 8.
(a) Define the rate of a chemical reaction.
(5)
Explain why increasing the temperature has a significant effect on
the rate of a reaction.
(6)
(b) The diagram shows a reaction profile diagram for an endothermic reaction.
Name the quantities of energy marked A and B.
Copy this diagram into your answer book and indicate clearly on your diagram
the likely effect of adding a catalyst on the energy profile for the reaction. (12)
(c) Catalytic converters are fitted to all modern cars with petrol engines.
Name two elements used as catalysts in a catalytic converter.
Name one substance which poisons the catalysts in a catalytic converter. (9)
(d) The oxidation of potassium sodium tartrate by hydrogen peroxide catalysed by cobalt (II) ions provides
evidence for the intermediate formation theory of catalysis. State the observations you would make when carrying
out this experiment. Explain how these observations provide evidence for the intermediate formation theory. (18)
2. 2004
(a)
(b)
(c)
(d)
2005
Question 8.
DEFINE: change in concentration per unit time
[Do not accept ‘mass’, ‘volume’, ‘quantity’, ‘amount’ in place of concentration]
EXPLAIN: More (greater number of) collisions reach (exceed) activation energy OR more
collisions have enough energy for reaction OR more effective collisions (6)
[Allow (3) for ‘greater number of high energy collisions’, ’increases energy (velocity, speed)
of particles (molecules, reagents, collisions)’ or ‘more collisions’ have the activation energy’]
NAME: A: Activation energy [Accept Ea or Eact] (3)
B: Heat of reaction / Heat change / ΔH / Heat absorbed / Enthalpy change (3)
[Accept ‘energy’ for ‘heat’]
COPY:
Reduction in activation energy shown (3)
Products line shown above reactants line / same ΔH with and
without catalyst (3)
(5)
ELEMENTS: platinum / palladium / rhodium [Allow symbols]
ANY TWO: (2 x 3)
POISON: lead [lead compounds e.g. tetraethyllead] [Allow symbols] (3)
OBSERVE: pink at start of reaction [Accept red] (3) // then bubbling as (3) // reaction mixture turns
green (3) // reaction finishes and mixture turns pink again (3)
(9)
(6)
(6)
(6)
(12)
Question 3.
Hydrogen peroxide decomposes rapidly in the presence of a manganese (IV) oxide (MnO2) catalyst.
(a) Write a balanced equation for the decomposition of hydrogen peroxide.
(5)
(b) Draw a labelled diagram of an apparatus a student could assemble to measure the rate of decomposition of
hydrogen peroxide in the presence of a manganese (IV) oxide (MnO2) catalyst. Indicate clearly how the reaction
could be started at a time known exactly, and how the gas produced is collected and its volume measured.
(12)
(c) A student has a choice of using the same mass of finely powdered manganese (IV) oxide or coarsely
powdered (granulated) manganese(IV) oxide. Which of these would you expect to have a greater average rate of
reaction over the first minute of the reaction? Give a reason for your answer.
(6)
A set of results obtained in an experiment to measure the rate of decomposition of hydrogen peroxide, in a solution
of known volume and concentration, is given in the table.
(d) Plot a graph to illustrate the volume of oxygen produced versus time.
(12)
(e) Use the graph to determine (i) the volume of oxygen produced during the first 2.5 minutes and (ii) the
instantaneous rate of the reaction at 2.5 minutes.
(9)
(f) What changes would you expect in the graph if the experiment were repeated using a solution of the same
volume but exactly half the concentration of the original hydrogen peroxide solution?
(6)
2005
(a)
(b)
(c)
Question 3
EQUATION: 2H2O2 → O2 + 2H2O / H2O2 → ½O2 + H2O [Formula 3 balancing 3]
DRAW: reaction vessel with hydrogen peroxide and catalyst (3)
method of ensuring correct start time e.g. catalyst in neck of horizontal flask; bring flask to
vertical and start clock / (3) [N.B. Descriptions of starting reaction and clock at same time must be
clear. Adding peroxide from funnel is not acceptable as start time is not exact and volume collected is
incorrect due to displacement of air.] /
delivery tube connected to gas collection system (syringe or over water) (3)
clear method of measuring (e.g. syringe with calibrations or inverted graduated cylinder) (3) [At least
one label required]
WHICH: finely (3)
(5)
(12)
(6)
3. (d)
(e)
(f)
2006
(i)
(ii
)
REASON: greater surface area available (3)
GRAPH: labelled and scaled axes [Accept “time” or “minutes”; “volume” or “cm3”.] (3)
points plotted correctly (6)
[Allow 3 marks if six or more points plotted correctly; assume (0, 0) is plotted correctly]
curve drawn [has to be drawn to (0, 0)] (3)
Note: the (6) for points plotted correctly not given if graph paper not used.
26.5 – 28.5 cm3 (3)
USE : 6.0 – 8.0 cm3 min-1 [Accept in cm3 s-1] (6)
[For answers outside range, (3) may be given for a good tangent drawn at the correct point]
WHAT: rise less steep / levels off later (3)
maximum volume 20 cm3 / half the final volume / less oxygen produced (3)
Note: changes may be shown on the candidate’s graph paper or through a suitable sketch
(12)
(3)
(6)
(6)
Question 7
(a) Define the activation energy of a chemical reaction.
(5)
(b) Give two reasons why the rate of a chemical reaction increases as the temperature rises.
Which of these is the more significant? Why?
(12)
(c) Describe how you could investigate the effect of temperature on the rate of the reaction between a 0.1 M
sodium thiosulfate solution and a 2 M hydrochloric acid solution.
(12)
The reaction is described by the following balanced equation.
Na2S2O3 + 2HCl → 2NaCl + SO2 + S + H2O
(d) When silver nitrate and sodium chloride solutions are mixed a precipitate appears immediately. Explain the
speed of this reaction compared to the slower reaction when solutions of sodium thiosulfate and hydrochloric acid
are mixed.
(6)
(e) What type of catalysis occurs in the catalytic converter of a modern car? Give the names or formulas of two
substances entering a car’s catalytic converter and the names or formulas of the substances to which they are
converted in the interior of the catalytic converter.
(15)
2006
(a)
(b)
(c)
(d)
(e)
Question7
DEFINE: minimum energy required for colliding particles (molecules) to react / minimum
energy required for effective collisions between particles (molecules)
[Accept ‘energy needed for colliding particles to initiate reaction’. Do not accept Ea diagram]
[Allow (3) for ‘energy required for reaction to take place’]
GIVE: 1st reason: increased energy of collisions (particles, molecules, reactants) (3)
[Accept: more collisions (particles) reach activation energy, more collisions are effective]
2nd reason: more collisions due to increased velocity of particles (3)
WHICH: first reason above (3)
WHY: for same temperature rise increase in number of collisions very small compared with
increase in number reaching activation energy OR leads to more (increase in) effective collisions
OR more collisions reach activation energy (3)
[Accept ‘helps to overcome (exceed) activation energy’]
DESCR: heat known volumes of the solutions separately to a certain temperature mix, note
temperature*, (3) [*Accept a stated temperature]
and place reaction vessel over cross (X, mark), keeping at temperature (3)
record time for cross to become invisible and take rate as 1/time (3)
repeat for other temperature(s) (3)
WHEN: AgNO3 and NaCl present as free ions in solution / no bond breaking(dissociation) / For
Na2S2O3 and HCl covalent bonds must be broken (dissociated)
[Accept ‘AgNO3 and NaCl are ionic’ or ‘Na2S2O3 and HCl are covalent’ for (3) only]
TYPE: heterogeneous catalysis (3)
GIVE: first entering // first converted to (2 x 3)
second entering // second converted to (2 x 3)
[The two substances required can both be hydrocarbons or oxides of nitrogen.]
Entering
Converted to
Carbon monoxide (CO)
Carbon dioxide (CO2)
Hydrocarbon (or named or correct formula)
Carbon dioxide (CO2) & water (H2O)
Oxide of nitrogen (correct formula) Accept NOx
Nitrogen (N2) & oxygen (O2)
[Accept nitrogen (N2) on its own]
(5)
(12)
(6)
(6)
(6)
(15)
4. 2007
Question 9
(a) Define the rate of a chemical reaction.
Why does the rate of chemical reactions generally decrease with time?
(8)
3
(b) The rate of reaction between an excess of marble chips (CaCO3) (diameter 11 – 15 mm) and 50 cm of 20 M
hydrochloric acid was monitored by measuring the mass of carbon dioxide produced.
The table shows the total mass of carbon dioxide gas produced at stated intervals over 9 minutes.
Plot a graph of the mass of carbon dioxide produced versus time.
(12)
Use the graph to determine (i) the instantaneous rate of reaction in grams per minute at 4.0 minutes,
(ii) the instantaneous rate of reaction at this time in moles per minute.
(9)
(c) Describe and explain the effect on the rate of reaction of repeating the experiment using 50 cm 3 of 1.0 M
hydrochloric acid and the same mass of the same size marble chips.
(6)
(d) Particle size has a critical effect on the rate of a chemical reaction.
(i) Mark clearly on your graph the approximate curve you would expect to plot if the experiment were repeated
using 50 cm3 of 2.0 M HCl and using the same mass of marble chips but this time with a diameter range of
1 – 5 mm.
(6)
(ii) Dust explosions present a risk in industry. Give three conditions necessary for a dust explosion to occur.
(9)
2007
Question 9
(a)
(b)
(i)
(ii
)
(c)
(d)
(i)
(ii
)
DEFINE: change* in concentration per unit time / [* “increase” or “decrease” not acceptable for
“change”] [Accept ‘mass’ or ‘amount’, but not ‘volume’ or ‘quantity’, for ‘concentration’]
WHY: concentration(s) decrease [reactant(s) used up]
PLOT: labelled and scaled axes [Accept ‘time’ or ‘minutes’; ‘mass’ or ‘grams’] (3)
all points plotted correctly (6) [Allow (3) if six points are correctly plotted; assume (0, 0) is correct]
curve drawn [has to be drawn to (0, 0)] (3)
Note: award (6) for plotted correctly only if graph paper is used, otherwise 0.
USE 0.20 – 0.26 g min–1
[allow 3 marks for good tangent or 3 marks for calculation based on data points from candidate’s
tangent]
0.004 – 0.006 mol min–1
DESCRIBE: slower rate (3)
EXPLAIN: acid less concentrated OR rate decreases with concentration (3)
MARK: see candidate’s graph* [steeper at start; levels off sooner; reaches same height] (6)
[Allow (3) if description is fully correct but not shown on the graph]
[Allow (3) if two of the three conditions above are shown on the graph]
* not necessarily on graph paper
DUST: combustible dust particles // dryness // above certain concentration // source of
ignition // oxygen (air)* // enclosed space
ANY THREE: (3 x 3)
[*Can be picked out of description if clear that it is a condition.]
[Allow “build up” or “enough of dust” or “spread out” for “certain concentration”.]
[Allow “lack of ventilation” for “enclosed space”] [Do not accept “heat” for “ignition source”]
(4)
(12)
(6)
(3)
(6)
(6)
(9)
2008 Question 3.
(a) Hydrogen peroxide solution is an oxidising reagent. Draw or describe the warning symbol put
on a container of hydrogen peroxide solution to indicate this hazard.
(5)
(b) Write a balanced equation for the decomposition of hydrogen peroxide.
(6)
(c) Solid manganese(IV) oxide catalyst was added to a hydrogen peroxide solution at a time known
exactly and the rate of production of gas was monitored as the hydrogen peroxide decomposed. Draw
a labelled diagram of an apparatus that could be used to carry out this experiment.
(12)
(d) The table shows the volumes of gas (at room temperature and pressure) produced at intervals over
12 minutes.
(4)
5. Plot a graph of the volume of gas produced versus time. Explain why the graph is steepest at the beginning. (15)
(e) Use your graph to
(i) determine the instantaneous rate of gas production at 5 minutes,
(ii) calculate the total mass of gas produced in this experiment.
2008
Question 3
(a)
(b)
(c)
(d)
(e)
(i)
(ii)
2009
(12)
DRAW: circle with flames rising
WRITE: H2O2 → H2O + 1/2O2 / 2H2O2 → 2H2O + O2 FORMULA: (3) BALANCING: (3)
DRAW: apparatus with hydrogen peroxide and catalyst separate (3)
arrangement for mixing at a precise time (6) Completely unlabelled diagram (– 3)
graduated cylinder over water (3)
PLOT: axes accurately labelled with numbers // axes with correctly labelled units //
eight points accurately plotted // curve accurately drawn from origin (4 x 3)
Note: If not on graph paper, accuracy must be checked with ruler.
EXPLAIN: greatest rate OR highest concentration of H2O2 OR most collisions (3)
[Accept “rate decreases”. Do not accept “amount” for “concentration”.]
see graph
4.0 – 6.0 cm3 min–1 (from correctly drawn tangent) (6) [Allow 3 marks for tangent drawn at 5 minutes]
0.104 g [Accept 0.1] (6)
78 ÷ 1000 ÷ 24 = 0.00325 mol (3) × 32 = 0.104 (3)
(5)
(6)
(9)
(15)
(6)
(6)
Question 9
(a) Explain (i) activation energy, (ii) effective collision.
(8)
The effect of temperature on the rate of a chemical reaction was investigated using dilute solutions of hydrochloric
acid and sodium thiosulfate. Suitable volumes and concentrations of the solutions were used.
The reaction is represented by the following balanced equation.
2HCl + Na2S2O3 → 2NaCl + H2O + S + SO2
Describe how the time for the reaction between the solutions of hydrochloric acid and sodium thiosulfate was
obtained at room temperature.
(6)
In a reaction mixture what effect, if any, does an increase in temperature of 10 K have on each of the following:
(i) the number of collisions, (ii) the effectiveness of the collisions, (iii) the activation energy.
(9)
(b) The catalytic oxidation of methanol using platinum wire is illustrated in the
diagram.
State one observation made during the experiment.
Name any two products of the oxidation reaction.
What type of catalysis is involved in this reaction?
(12)
Explain one way in which the presence of the platinum catalyst
speeds up the oxidation of the hot methanol.
Explain how a catalyst poison interferes with this type of catalysis. (9)
Give another example of a reaction which involves the same
type of catalysis, indicating clearly the reactant(s) and the catalyst. (6)
6. 2009
(a)
Question 9
(i)
(ii)
(i)
(ii)
(iii
)
(b)
EXPLAIN: minimum energy required for colliding particles (molecules) to react /
minimum energy needed for effective collisions between particles (molecules) (5)
[Allow (3) for ‘energy (required) for reaction to take place’] [Do not accept EAct diagram]
reaches activation energy / results in reaction between colliding particles / results in product
(3)
DESCRIBE: mix and start clock (3) note time when cross cant be seen through the solution. (3)
EFFECT: small (slight, tiny, < 5 %) increase (3)
EFFECT: large (big, substantial, > 50 %) increase in effective collisions (3)
EFFECT: no effect / none (3)
STATE: wire (Pt) glows / flame / popping sound / odour of methanal (3)
NAME: methanal // hydrogen // water [Accept “carbon monoxide”]
ANY TWO: (2 x 3)
TYPE: heterogeneous / surface [Accept “surface adsorption (absorption)” but not “hetero”] (3)
EXPLAIN: lowers activation energy / reactants adsorbed / reactants brought closer on
surface / higher concentration on surface / reactants occupy active sites on surface / bond
stretching / reactant oriented correctly for reaction / activated complex formed on surface of
catalyst. (6)
POISON: preferentially adsorbed (chemically attached) on catalyst / blocks active sites / forms
bond(s) with catalyst, preventing other reaction(s) (3)
GIVE: reactant(s) (3)
catalyst (3)
Hydrogen peroxide (H2O2)
Manganese(IV) oxide (manganese dioxide, MnO2)
Nitrogen (N2) & Hydrogen (H2)
Iron (Fe) / Iron(III) oxide (Fe2O3)
Sulfur dioxide (SO2) & oxygen (O2)
Vanadium(V) oxide (V2O5)
Ammonia (NH3) & oxygen (O2)
Platinum/rhodium (Pt/Rh)
Ethanol (C2H5OH)
Aluminium oxide (Al2O3)
Ethanol (C2H5OH) Platinum (Pt)
Copper (Cu) / Nickel (Ni)
Hydrogen (H2) & Oxygen (O2)
Platinum (Pt)
Name/formula of cat. converter reactant Platinum (Pt) / Palladium (Pd) / Rhodium Rh
[Reactant and wrong catalyst (3) Reactant no catalyst: Award (3) for the reactant if normally catalysed.]
(5)
(9)
(3)
(3)
(3)
(27)
7. 2009
(a)
Question 9
(i)
(ii)
(i)
(ii)
(iii
)
(b)
EXPLAIN: minimum energy required for colliding particles (molecules) to react /
minimum energy needed for effective collisions between particles (molecules) (5)
[Allow (3) for ‘energy (required) for reaction to take place’] [Do not accept EAct diagram]
reaches activation energy / results in reaction between colliding particles / results in product
(3)
DESCRIBE: mix and start clock (3) note time when cross cant be seen through the solution. (3)
EFFECT: small (slight, tiny, < 5 %) increase (3)
EFFECT: large (big, substantial, > 50 %) increase in effective collisions (3)
EFFECT: no effect / none (3)
STATE: wire (Pt) glows / flame / popping sound / odour of methanal (3)
NAME: methanal // hydrogen // water [Accept “carbon monoxide”]
ANY TWO: (2 x 3)
TYPE: heterogeneous / surface [Accept “surface adsorption (absorption)” but not “hetero”] (3)
EXPLAIN: lowers activation energy / reactants adsorbed / reactants brought closer on
surface / higher concentration on surface / reactants occupy active sites on surface / bond
stretching / reactant oriented correctly for reaction / activated complex formed on surface of
catalyst. (6)
POISON: preferentially adsorbed (chemically attached) on catalyst / blocks active sites / forms
bond(s) with catalyst, preventing other reaction(s) (3)
GIVE: reactant(s) (3)
catalyst (3)
Hydrogen peroxide (H2O2)
Manganese(IV) oxide (manganese dioxide, MnO2)
Nitrogen (N2) & Hydrogen (H2)
Iron (Fe) / Iron(III) oxide (Fe2O3)
Sulfur dioxide (SO2) & oxygen (O2)
Vanadium(V) oxide (V2O5)
Ammonia (NH3) & oxygen (O2)
Platinum/rhodium (Pt/Rh)
Ethanol (C2H5OH)
Aluminium oxide (Al2O3)
Ethanol (C2H5OH) Platinum (Pt)
Copper (Cu) / Nickel (Ni)
Hydrogen (H2) & Oxygen (O2)
Platinum (Pt)
Name/formula of cat. converter reactant Platinum (Pt) / Palladium (Pd) / Rhodium Rh
[Reactant and wrong catalyst (3) Reactant no catalyst: Award (3) for the reactant if normally catalysed.]
(5)
(9)
(3)
(3)
(3)
(27)