Dilution Lab Report

Dilution Lab Report
Title: Dilution
Abstract: As the wavelength is increased absorbance will start at low and get higher before curving
to low numbers again, while transmittance will go from high numbers to low number and curve
back to high numbers. This was tested by placing a sample in a spectrometer and changing the
wavelength. The absorbance and transmittance were recorded for each wavelength change.
The molarity of a substance will get higher and the transmittance of the substance will get lower as a
substance is diluted. This is shown by diluting Indigo Carmine stock solution and determining the
molarity and transmittance for each step of dilution.
Introduction:
How does the absorbance and transmittance change when you change the wavelength on a
spectrophotometer? ... Show more content on Helpwriting.net ...
The concentration of the stock solution was found on the label and recorded in the lab notebook. It
was labeled in the notebook as solution #1. 60.00 mL was removed from the solution using a
volumetric pipet and was placed in a 100 mL volumetric flask. The solution was diluted to the mark
on the flask. It was then covered with a stopper and mixed gently. The flask was labeled solution #2.
50.00 mL of solution #2 was removed from the flask using the volumetric pipet and was placed into
a 100 mL volumetric flask. It was diluted to the line, stopped, and mixed gently. The flask was
labeled solution #3. 10.00 mL of solution #3 was removed with the volumetric pipet and placed into
a 25 mL volumetric flask and was diluted to the line. The flask was stopped and mixed gently. The
flask was labeled solution #4. The molarity for each of the four solutions was calculated and
recorded in data tables in the lab notebook. The absorbance at 600nm was found by placing a
sample of each solution in the spectrophotometer and recorded in the lab notebook data tables (Table
1B). A plot was made in Excel of the absorbance at 600nm vs. the concentration for each solution
(Graph 1B). An unknown Indigo Carmine solution was obtained. The absorbance of the solution
was measured and by the graph the concentration was
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The Effect Of Photosynthesis On The Absorbance Rate
Discussion The initial experiment was a success. As our treatment group spent more and more time
under the lights, the absorbance rate continues to decrease toward zero. Once our 30 minutes were
up, the absorbance rate in each tube was significantly lower than at the start of our experiment. In
contrast the two control groups did significantly lower the absorbance. Each control lacked one of
the vital aspects of photosynthesis, one being light, and the other being chloroplast. Neither of the
control groups (Control 1 or 2) showed any signs of photosynthesis. Control 1 was exposed to light,
but contained no photosynthetic organelles thus the absorbance throughout the 30 minutes varied
minimally, mostly staying stagnant. Control two which contained chloroplast but was not exposed to
any light failed to lower the absorbance at all and in fact increased the absorbance over the 30
minutes. However, the treatment group contained both and ultimately performed photosynthesis as
we expect therefore, confirming our assumption that chloroplast were the organelles required for
photosynthesis in plants and that light is required to perform said photosynthesis. The treatment
group, containing both the chloroplast and being exposed to light provided evidence that
photosynthesis was taking place as the absorbance lowered at each 10–minute interval. Having a
less absorbance would be desired because as DCIP became reduced we would expect the solution to
become more and more clear, thus less

The Effects of Environmental Factors on the Absorbance of...
Introduction
In this experiment, the gram negative bacterium Escherichia coli is being subjected to various
environmental factors that affect the rate of growth. These factors scrutinized were the different
types of nutrients, the intensity of aeration, or the temperature at which it was stored. The purpose of
this lab is to determine which factor affects the Escherichia coli the greatest. It is known that these
abiotic factors affect the rate of growth the greatest if they remain at the correct conditions for
living.
Escherichia coli and other bacteria will go through four phases; a lag phase, log phase, stationary
phase, and a death phase. In the lag phase, the bacteria reproduce fairly slowly, as they are preparing
for the rapid ... Show more content on Helpwriting.net ...
We took readings every 15 minutes, until the class was over which was at the 90 minute mark.
For the temperature and aeration trials, the test tubes of Escherichia coli with tryptic soy broth
(TSB) were measured using identical procedures as the nutrient trials were tested. Before every
sample, we had to re–zero the spectrophotometer with a blank test tube, and then we took the
reading from the cultured tubes. As we did for the nutrient experiments, we also took the readings
from the temperature and aeration samples every 15 minutes. The temperature test tube was
prepared by exposing it to room temperature (25°C), another test tube in an oven (33°C), and the
test tube in a lab oven which was slightly warmer, at 37°C.
In the aeration samples, one flask was stationary and it was exposed to the atmosphere. The second
sample was put in a regular flask, and placed in a shaking water bath. The third sample was placed
in an irregular shaped flask, which was also placed in the quivering water bath. After treatment, all
the samples were measured on the spectrophotometer, using the same procedure as the nutrient
samples and temperature samples.
Results
The results showed that the experimental data did not necessarily display the lowest MGT. For the
nutrient data, the MSG had a mean generation time of an hour, the MSGT had a doubling time of
less than 13 minutes, and the MSGTYE had a mean generation time

Determining The Unknown Concentration Of Cobalt (II) Solution
The goal of the experiment was to determine the unknown concentration of the provided Cobalt (II)
solution by using a spectrophotometer/colorimeter. The spectrophotometer was used on the
unknown solution to find the concentration of Cobalt (II). The concepts used from Beer–Lambert's
Law are the absorbance and concentration of the tested solution. The equation is A=EbC. A equals
absorbance, E is the constant when identifying the species measuring the wavelength, b is the
thickness of the solution, and C is the concentration of the solution. E and b are both constant, which
makes the concentration and the absorbance directly proportional. Results resembled the standard
curve and the connection of absorbance and concentration was used to estimate ... Show more
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Then we got then unknown Cobalt (II) solution and placed it in a cuvette to measure the light
transmittance recording it to three decimal places. Next, the unknown solution of Cobalt (II) was
placed in a 100 mL beaker and the DI water was placed in a smaller beaker to make transferring the
solutions easier. For the process of transferring each solution smoothly, a pipette will be used to
place the unknown solution and DI water into the 10 mL graduated cylinder. First, 100% of the
unknown concentration should be placed in a test tube ready to be put in the spectroscopy. Then,
using a clean pipette fill the graduated cylinder with 9 mL of the unknown solution and fill the rest
with DI water using a different clean pipette until 10 mL is reached. The concentration solution is
90%, and 10% is the DI water which makes the new mixture. The mixture that was just made will
then be poured into a test tube that is beside the 100% concentration of the unknown solution. The
process will then be continued by pouring 8 mL unknown solution and 2 mL of DI water into the 10
mL graduated cylinder to get 80% concentration solution; which is poured in the test tube that will
be placed by the 90% concentration test tube. Again, 7 mL of the unknown solution will be placed in
the graduated cylinder along with 3 mL of DI water, which makes 70% concentration solution and
30% DI water. The solution will then be poured into a test tube and placed by the 80%
concentration. Then, 6 mL of Cobalt (II) unknown solution was placed with a pipette into the 10 mL
graduated cylinder with 4 mL of DI water. Which makes 60% of concentration solution and 40% DI
water, and pour the new mixture into a test tube and place it next to the 70% concentration solution.
Take 50% of the unknown solution and place it in the 10 mL graduated cylinder along with 50% DI
water making the new

Lab Investigation : Cell Purple Dye Solution
The purpose of this lab investigation is to make 1 L of Pirate Purple dye solution. The claim states
that the use of the concentration and absorbance of the Blue 1 dye and Red 3 dye will lead to the
concentrations of the red and blue dye to yield 1 L of Pirate Purple dye. In order to understand
molarity or concentration, familiarity with the terms of solute, solvent, and solution are very
important. A Solute is a substance that is being dissolved by a solvent. A solvent is a substance that
is dissolving the solute. Solution is a solute of a homogenous mixture that is dissolved in a solvent.
With that being said, molarity is the moles of a solute divided by the liters of a solution (mol/L). In
accordance to concentration, absorbance is used ... Show more content on Helpwriting.net ...
After the serial dilutions of the red and blue dyes were taken, the molarity and absorbance for both
dyes were calculated. Using the MiVi = MfVf equation, the concentrations for each value of the red
and blue dye were separately calculated. Calculating absorbances calls for setting the correct
wavelengths of light for each dye. In this case, the 470 nm wavelength for red dye and the 635 nm
wavelength for blue dye was needed to find the maximum absorbances. The absorbance was found
by blanking the colorimeter and entering the concentrations. After both values of the absorbances
and concentrations were found, the values were then graphed in order to obtain the equation of the
relationship between absorbance and concentration. The concentrations and absorbances of the red
and blue dyes were used to find the concentration of the purple dyes. From the graph of the blue
dye, the linear equation for absorbance was y = mx + b. From that formula came the equation y =
7.915 x 104 (x) + 0.02489, where y represents absorbance, m is slope, x is concentration/molarity,
and b is the constant/y–intercept. The same set up was performed for the red dye, but the equation
produced was y = 1.045 x 104 (x) +.001298. The equations found when graphing absorbance vs.
concentration were used to find the concentration of the purple dyes. The absorbance for purple dye
3 on the red wavelength of 470 nm equaled 0.149 and 0.818 for the blue wavelength of 635 nm. For
purple dye 1

Part A shows how limited the range of the Spectronic 20...
Part A shows how limited the range of the Spectronic 20 spectrometer is. It did not measure
transmittances below 400 nm or above 575 nm. This means the light source emitted those
wavelengths of light so weakly they were not detected by the instrument. Figure 3 plots the relative
overall response of the Spectronic 20, the relative response of a phototube, and the relative lamp
intensities as a function of wavelength. The Spectronic 20 response curve shows a maximum
relative response at 512 nm with a transmittance of 88.3%. The phototube response curve shows a
maximum relative response at 400 nm with a transmittance of 100%. This means the light source
used in Part A emitted green light stronger than any other wavelengths and the phototube ... Show
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The Ocean Optics does not have this ability and fluctuations that deviate from the accepted value are
observed as shown by its residuals plot. The r2 value (see table 12 in Appendix A and table 13 in
Appendix B) shows that the data are more linear for the Cary 60 instrument (r2 = 1.00) than for the
Ocean Optics instrument (r2 = 0.994). The absorbances for the Cary 60 were more accurate than the
absorbances for the Ocean Optics when compared against accepted absorbance values (Appendix C)
for the absorbance accuracy and linearity portion of the experiment (tables 2 and 3). These
differences can be attributed to stray light and background corrections. Because the Ocean Optics
sample holder is exposed to outside light, it is more prone to scattered light error, which inflates the
absorbance expected. The Cary 60 does not suffer from this issue because it is in a dark
environment. Also, as previously discussed, the Cary 60 corrects for background whereas the Ocean
Optics instrument does not. The calculated percent stray light for the Cary 60 and Ocean Optics
measurements were 0.09% and 5.26%, respectively. The reason why these values were so different
is explained by the environment in which the measurements were taken. The Cary 60 analyzed

Absorbance And Concentration Lab Report
The formula for measuring concentrations (Molarity) is moles/ Volume. The molarity of the diluted
sample is 3.5 x 10^–6 M and the volume is .005 Liters. Then solve for moles by multiplying the two
knowns the product is 1.75 x 10^–8 moles. All existing moles came from the .001 Liters of the
unknown sample. The moles should then be divide them the volume, which is 1 ml. The final
answer of the unknown concentration is 1.75 x 10^–5 M.
Absorbance and concentration are directly related. So if .1 M has an absorbance of .26, then a
solution with 0.2 M must have an absorbance of 0.52.
The formula to convert absorbance to transmittance is Transmittance = 10^–absorbance. The
equation would be 10^–.85 and the transmittance would be .1412 or 14.12% Transmitted.
Results and Discussion: ... Show more content on Helpwriting.net ...
In this experiment 10 cuvettes were filled with the appropriate dilution, an additional cuvette should
be filled with distilled water which should be used to calibrate the colorimeter. Record the
absorbance and transmittance for each dilution generated from the Webquest. Additionally, two
samples of Gatorade contains Blue Dye #1 (Low Calorie and Glacial Frost) were tested and found
that the Low Calorie Gatorade had an absorbance of .135 and the absorbance of the Glacial Frost
Gatorade was .153. Using linear regression the concentration of the two samples can be found if the
value of transmittance is substituted for the Y value. The concentration of sample 1 is 62.8 µM and
the concentration of sample 2 is 69.68 µM respectively reporting in four significant

Tube 1 And 2 Lab Report
Tube 1 and 2 contain functioning enzyme extract and substrate solution, ribose–5–phosphate.
Furthermore, the conditions in tube 1 and 2 allow the reaction to proceed to form ribulose–5–
phosphate and the mount of product formed can be measured. With tube 1 and 2 being identical,
averaging the absorbance allowed minimizing the error due to differences in enzyme concentration
and contaminants within experimental procedure. Tube 3 is used to boil the enzyme extract to
investigate the relationship of temperature on the rate of pentose–5–phosphate isomerase activity.
Tube 4 and 5 act as controls for the absorbance and the effect of substrate and enzyme on the
absorbance reading are investigate respectively. Tube 6 acts as a comparison for the known amount
of product whereby the absorbance of other tubes can be compared to tube 6 in order to calculate
amount of ribulose–5–phosphate present. Lastly, tube 7 acts a black for all the other tubes (1–6)
because it only contains tris buffer. The effect of ... Show more content on Helpwriting.net ...
Secondly, the sum of tube 4 (no enzyme) and tube 5 (no ribose–5–phosphate) were used to adjusted
the absorbance of tube 1 and 2 after using tube 7. As tube 4 only takes ribose–5–phospahte and tube
5 only contains the enzyme extract, by taking the difference of the sum of these two values from the
absorbance of one the full tubes (tube 1 or 2) it allows to account for the absorbance caused by
ribose–5–phosphate and the enzyme extract. And the adjusted absorbance will indicate only the
absorbance of the red complex formed by reaction between resorcinol–hydrochloric acid and
ribulose–5–phosphate. Lastly tube 3 (boiled enzyme) is not used as denatured enzyme has a
different absorbance compared to active enzymes, thus tube 3 cannot be used to adjust the
absorbance values (Kabacoff and Laken,

Finding The Absorbance Value And T % Of Cobalt
OBJECTIVE:
The purpose of the experiment was to find the absorbance value and T% of cobalt (II) nitrate
solutions at various wavelengths. Using Beer's law to determine the concentration of an unknown
cobalt (II) nitrate solution with the %T and A values of the known Cobalt (II) nitrate concentrations.
THEORY:
The purpose of this experiment is to find out if we can identify an unknown Cobalt (II) nitrate
concentration by using Calorimetry. Calorimetry involves the use of light to determine a specific
solute in solution (Sullivan 238).A given molecule absorbs particular frequencies of light and passes
others. If we are able to determine the degree in which various frequencies are absorbed, the
population or concentration of a given molecule in solution can be determined. In this experiment
we are trying to find out the visible spectrum of the known Cobalt (II) nitrate solution by using
absorption versus the wavelengths to determine the analytical wavelength. Once the analytical
wavelength is found we can use that to identify the unknown Cobalt (II) nitrate solution, by using
the Beer's law.
Beer's Law is a direct liner relationship between the absorbance of light are a selected wavelength
and the concentration the absorbing species in the solution. (Sullivan 241). Beer's Law shows a
relationship between several concentrations. To determine if the determine our data consistent with
Beer's law, we will plot a graph of absorbance versus concentration with a linear regression

Questions On The Quantification Of Light Absorption And...
Quantification of 〖Cr〗^(3+) and 〖Co〗^(2+)in a Mixture
Natalia Nole
Last updated: September 12, 2016
Purpose
Let's assume that we have two solutions, a clear and a colored one, whose concentrations and
identities are unknown. If we shine some light of some intensity towards them; some of this light
will go through and some of it will be absorbed. This is important because based on the amount of
light absorbed by the solutions we can calculate their concentrations. This important and simple
principle is known as Beer's Lambert law; which states that the absorbance is proportional to the
product of the path length, the molar absorptivity and the concentration of a solution. The product of
molar absorptivity times path length gives the value of K, which is the slope. (Equation below)
A = Ɛ.Ɩ. C
K = Ɛ.Ɩ.
A=K×C
Spectrophotometry is the quantitative measurement of light absorption and transmittance as a
function of a wavelength. The instrument used for spectrophotometry is called the
spectrophotometer, and the way it works is as follows. Let's say we have a source of light, which
normally is a deuterium lamp. The beam of light projected by the bulb will hit the diffraction
gradient, which looks like a prism. Diffraction gradient will adjust so that only a specific wavelength
will make it through an exit slit that eventually hits the sample, whose identity and concentration is
unknown. Light absorbed and/or transmitted by the sample will be sensed by the detector which will
be

Oxidase Enzyme Lab
Title of lab: Temperature Affects the Activity of Enzymes
Name: Vanessa Derner Date: January 26, 2017
Purpose: The purpose of this exercise was to determine the effect of temperature on catechol oxidase
enzyme activity. The optimal temperature range was also determined for the same enzyme in this
experiment.
Results and Discussion: In this experiment, the effect of temperature on the rate of reaction was
determined as well as the color changes at the different temperatures both for the catechol oxidase
enzyme. The tubes were different temperatures. Tubes 1 through 4 were 22 °C, tube 5 was 4°C, tube
6 was 40°C, and tube 7 was 80°C.
The color in the different tubes varied due to the different conditions of each tube. Tube 1 had ...
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At 0 minutes, tube 2 had an absorbance of 0.175 because it only contained the clear catechol
substrate. Tube 3 had an absorbance of 0.775 because the catechol oxidase enzyme made the
solution darker. Tube 4 had an absorbance value of 1.081 because this tube contains both the
catechol substrate and the catechol oxidase enzyme, which react to form benzoquinone. The same
was true for tubes 5 through 7. Tube 5's absorbance was 1.065, tube 6's absorbance was 1.078, and
tube 7's was 1.059. At 10 minutes, Tube 2 had a decrease in absorbance to 0.106 due to little to no
reaction occurring. Tube 3 had an absorbance of .955 because it also had very little reaction
occurring. Tube 4's absorbance was 2.110 due the reaction between the catechol substrate and the
catechol oxidase enzyme, which was turning the solution brown. Tube 5 had an absorbance of 1.645
because the enzyme substrate reaction was also taking place, but at a slower rate than tube 4 due to
the lower temperature in tube 5. The absorbance in tube 6 was 1.833, which means that the reaction
at this temperature was occurring faster than tube 5, but slower than tube 4. Tube 7 had an
absorbance of 1.155 because the high temperature was denaturing the enzyme causing the reaction
to slow or even stop. At 20 minutes, the absorbance of tube 2 stayed about the same with 0.091.
Tube 3 had an absorbance of .902, which did not change much

How Varying Enzyme Concentrations Affect Absorbance Over...
How Varying Enzyme Concentrations Affect Absorbance Over Time in Potato Homogenate Mixture
Haille Armstrong
November 17, 2015
Biology 155 Laboratory–Tuesdays 6pm
Lab Partners: Kayla, Morel, Ryan
Abstract
Saturation of substrates was a phenomenon that was observed in Part II of the experiment. This was
referenced from later in the discussion. When the enzyme activity from this experiment was
compared to Enoch's work, (Enoch) it was stated that he found that in certain liver cells of rats,
enzyme activity would stop suddenly. The study proposed that the lower Enoch dropped the
substrate concentration within these cells, the less activity he could record. This proved to both his
data and to the date from this experiment that the substrate was necessary for catalysis, because as
enzyme concentration rose, substrates bound more quickly to the active site of an enzyme. Once all
substrates in the mixture were changed to products, the enzyme was stationary because it had no
more substrate to catalyze. This meant that in order for the reaction to continue, substrate
concentration had to increase.
Introduction
To understand how and why the experiment was performed, one must understand what enzymes and
substrates are. Enzymes are defined as proteins that are capable of speeding up a chemical reaction
by reducing the amount of activation energy needed to catalyze that reaction (Raven, Johnson and
Mason 2014). Enzymes regulate these biochemical processes

Methylene Blue Absorbance Range
In the first part of the experiment, best absorbance range was measured to be from 0.1228 to 1.8053
where error value was near zero. Methylene blue solution with an absorbance 1.8053 may indicate
problems with the accuracy of the detector (e.g., a photomultiplier) .Since the detector system
examines the transmitted light of the cuvette, the absorbance is calculated from this value. When
transferring the linear transmission unit to the logarithmic absorbance unit, the accuracy is
exponentially reduced with rising values. Based on the result obtained from part I, analytes in part II
were diluted in 1:20 or 1:10 to generate absorbances that were within this range. Compared to
theoretical Ctotal calculated from solution preparation in the second ... Show more content on
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Therefore, the greatest accuracy can be obtained by choosing wavelengths at which differences in
molar absorptivities are large. 1In the third part, the instrument was able to differentiate between
pure, light, and extra virgin olive oil. The UV/Vis is capable of analyzing samples based on the
amount of light or UV radiation they absorb. The three olive oils are visibly different shades of
yellowish–gold, meaning they absorb different wavelengths of light. Considering this, one would
expect the UV/Vis to be capable of determining the degree to which the are different with respect to
absorbance. The extra virgin olive oil had the highest absorbance because it is the least refined of
the three types (containing the smallest amount of oleic acid). Light olive oil is the most refined
(highest amount of oleic acid) and pure olive oil is a mixture of pure and extra virgin2. One would
be able to identify pure from light based on these definitions. The olive oil absorbance figure 12
shows that pure has a larger absorbance than light which is what one would expect. Therefore, a
higher percent concentration of oleic acid is directly related to a lower visible absorbance with
respect to olive

Absorbance Spectrum Lab Report
Plotting the Absorption Spectrum of Lettuce Leaf Extract November 14, 2012 Aim: To see how
chlorophyll pigments absorb electromagnetic radiation at different wavelengths, with the use of a
spectrophotometer to vary the wavelength of incident light, and then plot an absorption spectrum.
Hypothesis: The chlorophyll pigments of the spinach leaf's chlorophyll extract will absorb more
electromagnetic radiation at wavelengths which correspond to the wavelengths of colors other than
green, as chlorophyll is green and it will reflect green light. Collection of Raw Data Beaker | 50mL
beaker, same for each group | Filter paper | Semi–transparent, thin | Spinach leaves | 5 identical dark
green leaves | ... Show more content on Helpwriting.net ...
We were also careful about the concentration of the extract, as the transmittance of the extract at
first should be between 65% to 85%; when it is under 65% the solution is too concentrated and some
ethanol should be added, and when it is greater than 85% it is not concentrated enough. Another
crucial point was placing the cuvette of ethanol into the sample compartment and calibrating to
100% transmittance using the '100%T/0A' knob prior to placing the cuvette of extract, as it is
essential to zero the absorbance every time before qualifying the absorbance of the chlorophyll
pigments. With special attention to these details, the aim of the experiment was achieved. Although
we did achieve our aim, there were a few errors, limitations and weakness that obstructed us from
achieving the most accurate results. For instance, we should have read the instructions more
carefully, because due to misunderstandings we were not setting the spectrophotometer properly at
first, and we were able to realize it only after our teacher's help. Because of this lack of
concentration, we wasted a small amount of ethanol and extract since we used them with the wrong
settings and had to re–do that part of the experiment, and therefore we also wasted time.
Furthermore, we could have observed and recorded the data more attentively, and hence obtain more
accurate results for the

A Study On The Absorbance Measured At 440 Nm Within 2 Min...
for 2 min. The absorbance was measured at 440 nm within 2 min stirring period. The results were
compared against standard curve developed using a concentration gradient of Na2So4 with BaCl2
(De Zoysa et al., 2007).
3.15. FTIR of purified polysaccharide
FTIR (Fourier Transform Infrared Spectroscopy) spectra of the partially purified SP were
determined using FTIR spectrophotometer model 5700 (M/S Thermo electron Corporation, USA).
Polysaccharide powder (2–3 mg) was mixed with KBr and pressed into a disk. The whole IR
spectrum was analyzed with a scan range of 4000–400 cm–1. Thirty scans were taken with 4 cm–1
resolution. CO2 and H2O corrections were incorporated. Reproducibility of the normalized spectra
was ±2%. (Shanthi et al., 2014).
3.16. Testing isolates probiotic properties
3.16.1. Blood hemolysis
Hemolysis test was performed according to the method described by Guttmann and Ellar (2000).
Overnight cultures of isolated Enterococcus durans and Enterococcus hirae were streaked on blood
agar and incubated at 37°C for 24 h. Blood agar plates were examined for signs of hemolysis. Blood
hemolysis test was performed in duplicates.
3.16.2. Resistance to low pH
Isolates Enterococcus durans and Enterococcus hirae were tested for their ability to resist low pH
values as follow, 25 ml of sterile MRS broth adjusted to pH 6.4, 4, 3 and 2 was inoculated using 1%
(v/v) of an overnight culture, then incubated at 37ºC for 6 h. The absorbance at 620 nm was
monitored using

Absorbance Spectra For Different Gamma Doses Of PVA / Ag...
Fig. (1), shows the absorbance spectra for different gamma doses of PVA/Ag nanocomposite films
(b to b4). In the UV region, all the samples showed absorption band at 200 nm, which is mainly
assigned as transition between the Ag nanoparticles and poly(vinyl alcohol)[17]. No absorption in
the wavelength range 350–800 nm was observed for both samples (b and b1) exposed to 0 KGy and
25 KGy. This is due to the time of reaction and the gamma irradiation energy is not sufficient to
reduce all the AgNO3 particles to Ag nanoparticles. However, for the spectra of the samples (b2–b4)
exposed to (50, 75 and 100 KGy) clearly indicate, a peak starts emerging at 427 nm. In addition, this
peak intensity increases with increasing the γ irradiation ... Show more content on Helpwriting.net ...
This means that with increasing the γ irradiation doses lead to increase the density of Ag
nanoparticles in the nanocomposite films. Optical band gap (Eg) In order to determine the optical
energy gap (Eg) for the irradiated ﬁlms. The term (αhν)0.5 as a function of photon energy (hν) is
plotted using the Tauc´s relation [21]. Such plots for PVA/Ag nanocomposite ﬁlms without and with
γ irradiation are presented in Fig. (4). From the figure we observed that the values of Eg were found
to be 4.44, 4.10, 3.80, 3.70 and 3.67 eV corresponding to the samples b, b1, b2, b3 and b4,
respectively. It is clear that the value of Eg is 4.44 eV for sample b. This value of the optical band
gap on doping PVA with Ag nanoparticles may be attributed due to the formation of chemical
bonding between poly(vinyl alcohol) chains and Ag nanoparticles responsible for the generation of
localized states (charge transfer complexes (CTCs) between (HOMO) High Occupied Molecular
Orbital and (LUMO) Lower Unoccupied Molecular Orbital energy bands making the lower energy
transitions feasible [17,22]. A further change in the value of Eg for PVA/Ag nanocomposites has
been showed with increasing γ irradiation dose and approaches to 3.67 eV at the dose of 100 kGy.
This is attributed to γ irradiation stimulates the reduction of Ag ions embedded

Absorbance Values
Abstract:
Claims were made that manufacturers had improperly labeled protein concentrations on their
products. Concentrations of these three different protein–containing liquids, whole milk, soy milk,
and a protein solution were determined using a Bradford dye reagent and a spectrophotometer to
measure the absorbance of each. Absorbance of a set of standard known protein concentrations from
a range of 0.125 mg/ml to 2.000 mg/ml were measured using the spectrophotometer at a set
wavelength and this data was plotted. The equation generated from the best fit line of this data was
used to determine the unknown concentrations of the three different samples. These values were
then compared to the protein concentrations obtained from the corresponding ... Show more content
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This would indicate that either the food labels or the calculated data are incorrect. The data was
dependent on a linear relationship between absorbance and protein concentration. However, the
linear relationship was based on only seven data points, two of which were omitted due to
inconsistency, and was only representative up to 2.000 mg/ml protein concentration. Because the
data sample was small and covered a small range of concentrations, the food label concentrations
cannot be determined as inaccurate. The more likely cause would be that the linearity assumption of
the correlation between the absorbance and the protein concentration is

Chloroplasts Lab Report
Questions and Hypotheses
Experiment 1 Question: The main question that was addressed in the first experiment (Parts I and II)
was which cell fraction had the most photosystem activity, which would be proportional to the
number of chloroplasts present in the cell fraction. Photosystem activity is proportional to the
number of chloroplasts since the photosystems are active in the thylakoid membranes of
chloroplasts (Leicht and mcallister 2016). The amount of photosystem activity would be seen in the
relative absorbance values for each cell fraction under the given light conditions. The absorbance
would decrease as the DCIP electron acceptor (which is blue when oxidized) gets reduced (which is
colorless). "The amount of color change is expected to be proportional to the number of functional
photosystems, which in turn is proportional to the number of intact chloroplasts" (Leicht and
mcallister 2016). We knew that chloroplasts were required for photosystem activity, but we ... Show
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Figure 3 shows the absorbance readings of P2 broccoli cell fraction under the following light
conditions: white light, red light, blue light and green light. Based on the data in Figure 3, we can
see that both red and blue light decreased in absorbance while green light had a slight change in
absorbance. Figure 4 is related to Figure 3 because Figure 4 shows the total change in absorbance of
each of the specific light conditions. The data from Figure 4 was calculated by finding the difference
in the final (7 minutes) and initial (0 minutes) absorbance values for each of the light conditions in
Figure 3. Based on the data in Figure 4, it can easily be seen that red light had a higher change in
absorbance than blue light, and it can also be determined that green light had no decrease in
absorbance. Compared to the positive control, red light had the most change in absorbance which
means it had the most reduction of

Measuring The Absorbance Of Light Of A Reaction Between...
Title: Measuring the Absorbance of Light of a Reaction Between Potassium Iodide (KI) and Iron
(lll) Chloride (FeCl3 ) to Determine the Order and Rate Law Expression Introduction: The purpose
of this experiment was to determine the order and rate law expression of the reaction between KI
and FeCl3 . This was done by using a colorimeter to measure the absorbance of light of the solution
over time.Originally, both solutions of KI & FeCl3 are opaque, but when mixed the solution changes
to a darker yellow. The degree of color change (light absorption) throughout the experiment was
used to measure the rate of reaction via colorimeter. During each test, the concentrations of KI and
FeCl3 were altered to determine the effect of each reactant. ... Show more content on
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The contents of the beaker were quickly poured into the cleaned cuvette such that it was 3/4 full.
The cuvette was tapped on the tabletop surface to dissipate bubbles. The cuvette was placed within
the calorimeter, the hatch was closed and data collection began. After 200 seconds, data collection
was stopped. The Vernier interface was set to linear fit, and initial slope from the time between 20
and 50 seconds was recorded. The Vernier interface was reset, the cuvette was taken out of the
Colorimeter. The cuvette's contents were poured out and cleaned via KimWipe. The contents of the
beaker were disposed of and the beaker was cleaned and dried. The previous steps were repeated
using measurements of FeCl3 and KI listed in the specific iteration. Once all the iterations were
completed the experimentation process was stopped. Analysis The motivation of this lab was to
determine the rate law of the reaction between KI & FeCl3, the rate orders of the reactants, and the
rate constant. Different concentrations of FeCl3, KI, and water were used through multiple
iterations. The initial rate of each iteration was found. Data gathered from the trials was used to
determine the rate orders. The rate order of FeCl3, calculated from the results of trials 1 & 3 was
0.604. The second rate order of FeCl3, which was calculated from the data of trials 2& 5, was

The Physics Of The Gas Of A Solution And The Amount Of...
Multiple scientific concepts were exemplified in this experiment and one particular goal of this lab
was to learn more about the Beer–Lambert Law which establishes a linear relationship between the
concentration of a solution and the amount of light that the solution absorbs. Moreover, another
objective of this experiment was to gain an understanding about the mechanical components of a
spectrophotometer and to successfully use the device to measure absorbance or transmittance
values. Lastly, another goal of this lab was to understand the concept of calibration curves and the
process of interpolating data. Essentially, this lab utilized all of the processes mentioned above to
determine the percentage of copper in a penny. Standard ... Show more content on Helpwriting.net
...
Introduction
Scientific Background Concepts The determination of the amount of copper in a penny involves
multiple scientific concepts that are extremely important. First, the experiment involves a redox
reaction of Copper and Zinc. Copper and zinc are both components of a penny and the oxidation
reaction utilizes nitric acid, a very strong oxidizing agent, in order to oxidize both copper and zinc.
The reaction generates a highly toxic, brown gas which is nitrogen dioxide (NO2), but more
importantly, it results in the complex ions of copper and zinc. The complex ion generated of copper
is Cu(H2O)42+ and has a dark blue hue while the complex ion generated of zinc is Zn(H2O)42+
and does not have a distinctive color. Essentially, a complex ion is formed by having a central metal
ion that has formed covalent bonds with multiple ligands, which are simply anions. Furthermore, the
Beer–Lambert Law establishes a relationship between light absorption and solution concentration by
claiming that the concentration of a certain solution is directly proportionate to the total amount of
light energy that the compound present in the solution can absorb (The Beer–Lambert). A
spectrophotometer can be utilized to measure how much light energy of a certain chosen wavelength
is absorbed by a particular sample.
Objectives
There are multiple goals that are to be achieved by

The Weight Molecular Weight Of Pectin
The average weight molecular weight of pectin as shown in Fig.3, Pectin showed two molecular
region bands between 7.85×105 and 2.42×105Da, with highest abundance at 7.85×105 Da, the
0.35%SHMP extracted pectin sample had average molecular weight of 3.785x105 Da. The
molecular weight was in the same range (7.85×105 and 2.42×105 Da) previously reported by
Takamine et al., (Takamine et al. 2007). The high molecular weight could be attributed to fast drying
of residues which inhibited pectinase enzyme action on pectin, besides SHMP is known not to cause
pectin hydrolysis, unlike acid or alkali solution extraction which tend to hydrolyze pectin through
beta–elimination (Diaz et al. 2007). The molecular weight of pectin depends upon its source, method
of extraction and treatment it undergoes after extraction (Fishman et al. 1984). High molecular
weight in extracted pectin indicates that the pectin was not hydrolyzed during extraction. Pectin
extracted from creeping fig had molecular weight ranging from 78.6, 251 and 359.2kDa for HCl,
sulphuric acid and hot water extracted pectin, respectively (Liang et al. 2012), the low molecular
weight of acid extracted pectin was attributed to acid hydrolysis of pectin. In the same breath hand
acid extracted chicken pea pectin had molecular weight of 110kDa (Urias–orona et al. 2010). It is
worth noting that, the molecular weight of carbohydrate is not easy to determine partly owing to
their polydisperse nature, association at higher

Water Absorbance Test Lab Report
Results The absorbance of five substances _ sphagnum, true sponge, artificial sponge, and paper
towel was tested with 5g of each material and 250ml of water for each. The materials were left to sit
in the water for two minutes after which they were removed and the water left was measured.
sphagnum, which had the least absorbance left 245ml of water, which means it absorbed 5ml of
water; second is paper towel whose beaker had 225ml left, that is, it absorbed 25ml of water; the
third which is artificial sponge left 210ml of water in the beaker, which means it absorbed 40ml of
water; finally true sponge with the most absorbance left 190ml of water and absorbed 60ml of water
(Table 1). Table 1. Water absorbance results Material Amount of water ... Show more content on
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Although the way the sphagnum was described in the lab manual, in the sense that "many gardeners
use sphagnum in their yard because of its ability to absorb water", made it look like there would be a
twist in the result, and that the sphagnum would actually absorb more water, the hypothesis was in
fact proven right because the true sponge did absorbed the greatest amount of water, followed by the
artificial sponge, then paper towel, and finally sphagnum. This actually makes sense because all the
substances are porous and permeable so they should all absorb at least little quantity of water.
Porosity and permeability are properties of solids that affect their absorbance. Porosity is the extent
to which space is present within the solid, while Permeability is the ability of a solid to prevent or
allow the passage of liquid. The higher the number and size of pores in a, the easier it is for liquid to
pass through it. Accordingly a solid with high porosity is most likely to have high permeability
(Kearsley and Wainwright, 2001). Although paper towel had larger surface area, it was not as thick
as the sponges and so it absorbed lower amount of water, in addition, the true sponge was thicker
than the artificial sponge.

Spectrophotometer: Concentration and Standard Curve Essay
Lab Report 4
Biology 103
Prof. Dr. Johnson
Spectrophotometer; the finding of protein concentration of an unknown sample of BSA, and by
using the standard curve.
Abstract A spectrophotometer's purpose is to use colors of the light spectrum to determine the
concentration of light absorbing molecules in a solution. (p.59) In this particular lab, our mission
was to determine the protein concentration and the standard curve of the unknown sample of BSA.
This, by preparing five dilutions of the unknown solution of BSA together with other known
concentrations, and then experimenting by observing how the concentrations were passed through
the spectrophotometer. The outcome resolved in the absorption levels being decreased, and this ...
The same solution of 0.5 ml BSA was then added from test tube 1 to the test tube 2 after being
properly mixed, and from test tube 2 the solution was being added to test tube 3, and so forth all the
way up to test tube 5, with the same exact procedure. From the last tube, we then disposed the 0.5
ml solution. After above procedures, we now labeled another test tube "blank"; 0.5 ml blank distilled
water was purred into the tube with the serial dilution of 1:10. We also had a tube C labeled
"unknown" with the same 0.5 ml of solution. And after adding 5ml of Coomassie Blue to each tube
(1–5) and to the blank, the result of absorbance was read at 595 nm.
Result | Protein Concentration(µg/ml) | Absorbance(595 nm) | Tube 1 | 120 | .922 | Tube 2 | 60 | .557
| Tube 3 | 30 | .377 | Tube 4 | 15 | .180 | Tube 5 | 7.5 | .082 | Unknown: .759 |
The ending result of this experiment confirms that as five test tubes are lined up with the varying
level of absorbance, different results in the level of absorbance will appear as well, this is visible in
above table. Thus, this is due to the varying amount of water in the solution. The blank sample had a
0.30 in its level of absorbance.
Calculating serial dilutions and their concentrations
(Examples of test tube 1 and test tube 2for respective dilution and concentration)
Dilution or D = previous dilution (if any) ×the

Paper Chromatography Essay
Results: The pigments that were obtained through the use of paper chromatography resulted in four
distinct colors. The very goal of this study was to determine what pigments are present and what
there absorbance is through the use of paper chromatography and a spectrophotometer. These colors
in turn related to pigments that were recognized as chlorophyll a, chlorophyll b, carotene, and
xanthophyll. As for the results related to the observations found within the paper chromatography,
these four pigments had a distinct relational pattern within the filter paper. This resulted in the order
of color from top to bottom of the filter paper being: carotene (orange), xanthophyll (yellow),
chlorophyll a (dark–green), and chlorophyll b (light green). In the methods I recorded the following
results of the paper chromatography experiment (see figure 2). ... Show more content on
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Chlorophyll a had the highest absorbance rate resulting in readings peaking at 0.7. Xanthophyll had
one of the lowest absorbance reading peaking between .2 and .22. Carotene had the second highest
absorbance reading at 0.44 and the wavelength of 460. Chlorophyll b had a very close reading to
that of carotene resulting in a peak between 0.38 and 0.41. Within the data of chlorophyll a and
chlorophyll b, one will notice a general pattern of increase, decrease, and lastly a smaller increase.
Carotene and xanthophyll have only one major peak within the absorbance

Lab Report: Optical Absorbance And Quantitation Of Light A
Title: Optical Absorbance and Quantitation of Light Absorbing Molecules
Name: Kaylen Meeks
Lab Partner: Quin Waterbury
Date Experiment Performed: 1/16/2018
INTRODUCTION
Stock solutions are stored in freezing temperatures for long term storage in many biochemistry labs.
The freezing and thawing of these solutions will influence the concentration. To display this
phenomenon, ampicillin that had been frozen was thawed. Samples were taken at various times and
their absorbances were measured with a spectrometer. Absorbance is directly correlated with
concentration with the following equation, known as the Beer–Lambert Law: A=εCl. By measuring
the absorbance of samples taken at various times in the thawing process, their concentrations can be
found. This experiment will show the effect of freezing and thawing a solution on concentration.
METHODS ... Show more content on Helpwriting.net ...
A tube of ampicillin was taken out of the freezer. As soon as it is available, 10 µl of ampicillin was
removed from the tube and added to the first tube (labeled '1'). When about 1/10 of the solution had
been thawed, 10 µl of ampicillin was removed from the tube and added to the second tube (labeled
'2'). After the solution was fully thawed and mixed, 10 µl was removed and added to the third tube
(labeled '3'). Before measuring, each of the tubes was mixed thoroughly. Each tube was measured by
a spectrometer to find absorbance. The Beer–Lambert Law was used to find the concentration
(shown below in Table

Abstract:. This Experiment Was Conducted To Find The...
Abstract: This experiment was conducted to find the absorbance of light by blood glucose samples
taken from nondiabetics and diabetics taken before a meal and every thirty minutes for two hours
after the meal. The hypothesis for this experiment is that diabetics have a greater absorbance than
nondiabetics because diabetics cannot properly regulate their glucose levels. The samples were
taken before a meal then taken every thirty minutes after the meal over the course of two hours. This
samples were then put into a spectrophotometer to get the absorbance of each. These values were
recorded and averaged with the absorbance values from other groups within the lab. The absorbance
values show that the diabetic blood glucose samples have a ... Show more content on
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The absorbance value is related to the blood glucose because the higher light absorbance value, the
higher the amount of blood glucose concentration in the sample. The absorbance values that were
recorded from each lab table were averaged and put into a table. The values were then graphed in
order to see the differences between nondiabetic and diabetic blood glucose absorbance. The
hypothesis created for this experiment is that diabetics have a greater absorbance than nondiabetics
because diabetics cannot properly regulate their glucose levels. Methods: The solutions of
nondiabetic blood glucose and diabetic blood glucose are collected before a meal and every thirty
minutes after a meal for two hours to be tested for the level of blood glucose in each solution. Five
milliliters of each blood sample were then pipetted into individual cuvettes, so that the absorbance
of the glucose can be measured. The blank cuvette contained five milliliters of water. Water is an
appropriate blank for blood glucose samples because the samples are water based. This cuvette was
used to zero out the spectrophotometer, so the absorbance of the water in the blood glucose samples
can be subtracted from the full absorbance. The spectrophotometer was set to 540 nm before
inserting the first cuvette. The wavelength is set to 504nm because this wavelength is the
wavelength that is

Diabetic Absorbance
According to the experiment results the hypothesis was proven to be correct. The diabetics did
indeed have a higher absorbance level than the non–diabetics. It was made clear that the rate at
which a diabetic digests their meal is slower than a non–diabetic. It proves that fact that without
sugar, the body could not function properly because there would not be enough glucose in the body
to provide energy in order to make ATP. Without the main ingredient to make ATP the body would
die. This fact leads to the understanding as to why people with diabetes in third world countries are
dying because they cannot get the insulin needed in order to help their bodies make ATP and
function (Khunti).
As seen in figure one it is clear that it takes a diabetic longer to return to their pre–meal value
because it takes longer to break ... Show more content on Helpwriting.net ...
Also the diabetic would reach the maximum blood glucose level quicker because they could not
break down the glucose in the food as quick as the non–diabetic could. As seen in figure 1 it is clear
that a person with diabetics has almost double the absorbance level compared to the non–diabetics.
The data in figure 1 shows the absorbance over time for diabetics and non–diabetics. Looking
deeper into the meaning of why the absorbance is higher in the diabetic people it is known to be
because of the buildup of glucose in the bloodstream. This buildup leads to less glucose being able
to pass through and thus taking the diabetic longer to get back to the pre–meal value. The effects of
T2D can lead to this buildup and cause cardiovascular disorders, hypertension, and death. Diabetes
still not be taken lightly for this very reason. Unlike T2D patients type 1 diabetics(T1D) are at a
greater risk because their body does not produce insulin at all, thus making it harder to maintain and
regulate. T1D's are always having to check

Spectroscopy Lab Report
Introduction:
The purpose of this experiment is to analyze the absorbance values of standard fast green solutions
with differing known concentrations and one unknown concentration, as well as chlorophyll a and b
solutions at various wavelengths using spectroscopy.
The modern Beer Lambert Law is used for chemical analysis and is derived from two different laws.
Lambert's law described the relationship between a substance's absorbance and its path length. Beer
discovered that the absorbance of a substance is proportional to its concentration. These laws
combined to form Beer Lambert Law, which can be described as a linear relationship between the
factors of absorbance and the concentration of a light absorbing solute of a solution. Beer lambert ...
Magnetic resonance spectroscopy uses the methods of spectroscopy to perceive certain metabolites
within tissue samples and is similar to the process of magnetic resonance imaging. The same
equipment is used for both, but in magnetic resonance spectroscopy, concentrations of certain
chemicals within the body. This method is beneficial to the diagnosis of illnesses related to different
areas of the body such as cervical cancer and prostate cancer. Magnetic resonance spectroscopy has
also allowed for advances in understanding the development of the brain, mental illness, and
neurodegenerative diseases through determining metabolic abnormalities. This procedure is
noninvasive, allowing for a smarter alternative to measuring response to disease treatments as well
as detecting such diseases (Parker, 2012). Another important application regarding spectroscopy
includes the use of Fluorescence spectroscopy to identify bacteria associated with inflammatory
diseases of the middle ear as well as other forms of bacteria that cause illness. For each type of
bacteria, fluorescence spectroscopy can be used to determine the spectral variances between each,
allowing for a noninvasive technique for diagnosing such inflammatory diseases. Fluorescence
spectroscopy provides a diagnosis that is quick and efficient, with at least 90% accuracy
(Edetsberger, Gaubitzer, & Knapp,

Absorbance Values Of Bromothymol Blue : Acid-Base Color...
Bromothymol blue is an acid–base color indicator. The acidic form of bromothymol blue is yellow.
The basic form of bromothymol blue is blue. Therefore, a color change indicates that either a proton
has become lost or gained by the bromothymol blue. This color change can be associated with the
end point of a titration allowing the pKa to be calculated, as pKa will be equal to pH. The
absorbance values of bromothymol blue at different pH values were recorded using a UV–Vis
Spectrophotometer from 340–800 nm.
Figure 1 illustrates the absorbance values of pH 5.00 and pH 10.00 bromothymol standard solutions
that were recorded from 340–800 nm. The graph illustrates the maximum wavelengths observed at
each respective standard solution. This maximum wavelength value is important because it is the
wavelength with the highest sensitivity and can therefore minimize random error in the absorbance
values. Table 1 illustrates the different maximum wavelength values for the two standard solutions.
The acidic bromothymol standard solution had a maximum wavelength at a lower value than the
basic bromothymol standard solution (Table 1). These wavelength values are therefore associated
with the different colors of the standard solutions.
The bromothymol blue absorbance values were recorded at different pH buffers from pHs of 5.02–
9.01 (Figure 2). As the pH went from 5.02–9.05, the color of the bromothymol blue went from
yellow to blue. With each increase in pH, the color inside the cuvette

The Effect Of Various Shading Conditions On Absorbance
The effect of various shading conditions on absorbance was studied using chloroplasts from
Spinacia olderacea leaves. DCPIP assays can be used to assess photosynthetic activity because it is
an electron acceptor that absorbs light based on the amount of electrons transferred to it during
Photosystem II. Shade exposure will decrease the amount of photosynthesis the will occur, which
reduces the amount of electrons transferred to DCPIP and therefore there will be less of a change in
absorbance. Enriched chloroplasts were placed in conditions in which mesh was placed over light
sources that created 25% shading, 50% shading, and 75% shading. Tubes of chloroplasts were also
placed in no shading and completely dark conditions to serve as controls. It was hypothesized that if
the percentage of shade increases, then the percent change in absorbance will decrease. Absorbance
was tested using a Spectrometer at time zero, 10, 20 and 30 after the reaction began and the tubes
were placed in their conditions. The hypothesis was supported in this experiment because as
compared to the light, all of the shading conditions had caused a significant decrease in change in
absorbance, but a plateau was observed in change in absorbance over 50% shaded. Since each
shading condition did result in a significant decrease in percent change of absorbance, shading
techniques can be used to prevent superfluous vegetation growth because a decrease in percent
change showed diminished activity of Photosystem

Unknown Spectrophotometry
For unknown 1, we did 4 dilutions at the 4 concentrations listed in table 3. At 2μl of unknown,
triplicate absorbance readings were taken and the average absorbance was 0.6. On the other hand, no
further dilutions needed to be done for unknown 2, so three absorbance measurements at 10μl were
taken. The average absorbance for unknown 2 at low concentration was found to be 0.37. Since the
average absorbance at low concentration for 2 unknowns were found, we used equation 2 below to
determine their concentrations. The best–fit line of the linearity part of the standard curve produced
this equation.
The average absorbance of each unknown was plugged in for y and the diluted concentration was
determined by solving for x. To find the actual concentration of the unknown, x had to be multiplied
by the dilution factor ... Show more content on Helpwriting.net ...
They fall along the best fit–line, producing an R2 value of 0.99726. The equation that represents the
relationship between absorbance and concentration is y= 0.017x + 0.1733. Next part of the
experiment was to determine the absorbance of 2 unknowns at both high (100μl) and low (10μl)
concentrations. The result is shown in table 2

Beta Galactosidase Essay
"Chemical Kinetics"
Dev. Patel
Biology 1121 Spring 2016
27th February, 16.
Introduction–
Enzymes are molecules that catalyzes a chemical reaction by either increasing or
decreasing the chemical reaction up to an extent. Inhibitors are substances which slows
down a chemical reaction by reducing the activity of either a catalyst, substrates or the
enzymes. Most of the enzymes are proteins. They lower the activation energy of a certain
chemical reaction. Activation energy is a certain amount of energy required for the
reactants to convert in to products. If they cross the energy barrier, they convert in to
products. So enzymes don't allow the substrates to cross the barrier by lowering the
activation energy. Enzyme's characteristic ... Show more content on Helpwriting.net ...
(Advances in optical manufacturing). It also requires a certain wavelength of
light for calculating the absorbance. For this experiment, spectrophotometer was set to a
wavelength of 420 nm.
Hypothesis is an explanation for an observed phenomenon that can be tested. In this
experiment there are different factors affecting the enzyme activity like determining

baseline reaction kinetics, varying substrate concentration, effect of changing pH on
enzyme activity, and determining the effect of other factors on enzyme activity. Each factor
had a stated hypothesis like the enzyme activity will slow down for the substrate
concentration. For a pH closer to 7 the enzyme activity increases and adding galactose
which is the product increases the enzyme activity slowly. Hypothesis is a declared
statement.
RESULTS:
Part 1: Determining baseline activity of the enzyme beta–galactosidase
Table 1: Absorbance data for baseline kinetics Time (minutes)
Absorbance (A)
3
0.440
6
0.750
9
1.001
12
1.178
15
1.272
Graph 1:
For a total of 15 minutes the absorbance value was observed every 3 minutes giving a

Rat Law Determination of the Crystal Violet Reaction
Jeremy Li Wai Long Lam Experiment 9: Rate Law Determination of the Crystal Violet Reaction
Goals: Under stand 1st, 2nd , and 3rd order chemical reactions, learn graphing options available on
LogerPro Purpose: Determine the reaction order with respect to crystal violet for the reaction
between crystal violet and sodium hydroxide. Introduction: The rate expression for this reaction is of
the form: rate = K(CV+)M(OH–)N Where k = re constant, m is the order of the reaction with respect
to the concentration of CV+, and n is the order of the reaction with respect of OH–. In the
experiment the concentration of OH– is purposely made 1000 times larger then Concentration of
CV+. Thus, the concentration of OH– changes so little during the ... Show more content on
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Save. 9. Discared the solutions. The next step is to analyze the data graphically to see if the reaction
is zero, 1st or 2nd order with respect to crystal violet. The reaction is Zero Order – if the current
graph of absorbance vs time is linear First Order – if a plot of the natural logarithm (ln) of
absorbance vs time is linear. Second Order – if a plot of (1/Absorbance) vs time is linear 10. To
create a plot of the ln (absorbance) vs. time: a) Choose new column>Formula from the data menu
b) Enter "ln Absorbance" as the long name, "ln Abs" as the short name and leave the unit blank.
Then click on the definition tab. c) Choose "ln( )" from the function list as the formula for the
column in the equation edit box. Next Select absorbance from the variable list. In the equation edit
box, you should now displayed: ln ("absorbance"). Click Ok. d) A graph of the ln Absorbance vs
time should now be displayed. To see this relationship is linear, click the linear regression button.
Save and print. 11. To create a plot of (1/Absorbance) vs. time a) Choose new column>formula
from the data menu b) Enter "1/absorbance" as the long name, "1/abs" as the short name and leave
the unit blank. Then click on the definition tab. c) Type 1 then / in the equation edit box. Next select
"absorbance from the variables ist. In the equation edit box, you should now see displayed:
("1/absorbance"). Click Ok.

Maximum Absorbance Of Fast Green And Chlorophyls
The overall purpose of this experiment is to find the maximum absorbance of Fast Green and
chlorophylls a and b. The concentration curve of Fast Green was used to determine the unknown
concentration of unknown #17. Different techniques, graphical or experimental, were used in this
experiment such as absorbance spectrum graphs and the use of blanks to recalibrate the
spectrophotometer. Light is a part of the electromagnetic spectrum that varies in wave from radio
waves to gamma rays. The human eye can only detect the visible light portion of the spectrum; a
range of wavelengths (nm) from 400 nm to 700 nm. Electromagnetic radiation can be described as a
stream of massless particles called photons that move in a wavelike motion at the speed of light. A
spectrophotometer is an instrument used to measure the amount of amount of photons (absorbance
of light) that passes through a sample solution over a given wavelength. It does this by using a white
light source that travels through a prism, the prism separates the white light into narrow portions of
the radiant energy. The ... Show more content on Helpwriting.net ...
Fast Green is used for specific staining procedures, for example protein, where is it used to better
illustrate the presence of histones through a marker dye. For this part the experiment, the objective is
to achieve the concentration curve of five known concentrations to find the unknown concentration
through Beer–Lamberts Law. The concentration curve is also known as the calibration curve, both
involve a graph with the concentration variables on the abscissae and the absorbance numbers on the
ordinate. The absorbance spectrum of the Fast Green solution must be determined before obtaining
the concentration curve. The maximum absorbance of the solution must be determined through the
absorbance spectrum. The wavelength at the maximum absorbance was used to determine the
absorbance for the diluted Fast Green

Absorbance Experiment With Turnip Peroxidase
Introduction
Enzyme can be defined as a protein molecule that is a biological catalyst. (Ophardt, 2003) Catalyst
increases the speed of a reaction but does not have to use anything to help increase the speed. An
enzyme can be determined by their properties. Enzyme are a substrate specific, substrate connects to
an enzyme at the location of an active site. Enzyme is not used in a reaction and enzyme function in
a good condition at the optimum temperatures and pH. (Ahmez2005) Peroxidase is a type of enzyme
which is used in the experiment.
The type of peroxidase is used is called turnip peroxidase. Turnip peroxidase is made up of Guaiacol
and hydrogen peroxide. The reactants to the product are turnip peroxidase or called tertraguaiacol
and water. The color of the react is brown. In the experiment was conducted there were baseline
experiment, temperature, pH, 10X substrate, Inhibitor, and half the amount of enzyme.
The baseline experiment is the control group. If the time increases over a period a time then turnip
hydrogen peroxidase will increase absorbance.
The temperature can have a major impact on an enzyme. According to Campbell Biology author
Reece etc. 2011 "The enzyme reaction will increase as the temperature increase with the increasing
temperature....substrates collide with active sites more frequently when the molecules move
rapidly."(Reece etc 2011) Every enzyme hits its optimal temperature the reaction will be at its
highest point.(Reece etc. 2011) When the

Absorbance and Spectrophotometry
Experiment 2: Absorbance and Spectrophotometry
ABSTRACT:
This was an investigation into the effects of different wavelengths of light on methylene blue and
carmine red on the absorbance value on a spectrophotometer. A spectrophotometer is used to
measure light intensity by emitting a single light source through a cuvette of coloured solution. The
particles in the solution, which are coloured, absorb the light depending on how concentrated it is
and this produces an electronic reading from the photometer which is the absorbance value. The
maximum absorption was found for both solutions and was used to calculate the molar extinction
coefficient of methylene blue. An unknown concentration of methylene blue was calculated by using
... Show more content on Helpwriting.net ...
Figure 4. Graph showing dilutions of methylene blue and the absorptions each solution gives
The black line on figure 4 represents the regression line. We can use this to find the concentration of
the unknown concentration of methylene blue solution by drawing a tangent to the regression line at
absorbance 0.262 (where the unknown absorbed) and reading down from that point on the graph to
the concentration. The concentration of the unknown methylene blue is 4.4 x 10–6 mol dm–3.
We can find the molar extinction coefficient by substituting values of absorbance and the
concentration of the unknown concentration of methylene blue into Beer's laws equation.
Absorbance = k c t
k = absorbance / c t
k = 0.262 / 4.4 x 10–6 x 1
k = 59545 mol dm–3 cm–3
Therefore, k, the molar extinction coefficient is 59545 mol dm–3 cm–3.
DISCUSSION:
The main objectives of this experiment was to find the unknown concentration of methylene blue by

using a spectrophotometer. I found the maximum absorption for methylene blue and carmine red
(please refer to figure 1) and using this I determined a more accurate maximum absorption value for
each solution by taking further readings around the peak of each line to determine the maximum.
However, the findings of maximum absorption for methylene blue and carmine red may not be as
accurate as we think

Creating The Unknown Concentration Of Cu + 2
Creating Solutions of Standard Molarity
Madelene Andersson
Sarah Toadvine
CHEM 1251L–013
10/13/2014
Introduction: The purpose of this lab is to find the unknown concentration of Cu+2 by comparing
the solution to a set of standard concentrations, different known concentrations, which are prepared
by diluting approximately 2.5 grams of copper (II) sulfate pentahydrate. A concentration is the
amount of solute relative to the volume of a solution, the more solute the more concentrated the
solution will be. Concentrations are reported using molarity (M) which is the moles of the solute by
the volume of solution in liters. A spectrophotometer called the Spec 20 and the Beer–Lambert law
is used to determine the concentrations of solutions. The Spec 20 is used to measure the amount of
light that passes through a solution. This is measured in terms of absorbance which is the amount of
light a solution absorbs or transmittance which is the amount of light that passes through a solution.
The relationship between absorbance and transmittance is A= –log T or A=2–log (%T).
The Beer–Lambert Law establishes the quantitative relationship between absorbance and a
solution's concentration.
The formula is A=ԑbc
A=absorbance
ԑ=molar absorptivity constant b=the path length (cm) through which light travels c=molar
concentration of solution
The Beer–Lambert plot (absorbance vs. concentration) establishes a calibration curve that is used to
determine the concentration of a solution of the same

Dilution Lab Report

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Dilution Lab Report