Lab final HOL
1
Directions:
Answer the following questions on sheets of paper. Upload your answers as a single pdf file to Canvas in Module 6 under the lab final
heading by the due date. NO LATE LAB FINALS ARE ACCEPTED. Make certain that you show all your calculations (with
co
ect units and significant figures), and that you answer any questions with complete sentences. It is ok to compare answer with
your peers; however, any answer you provide must be in your own words!!!
1. Chemical Kinetics Experiment
Student runs a chemical kinetics experiment following the method of initial rates.
1) The data in the table below were obtained for the reaction:
2 ClO2 (aq XXXXXXXXXXOH- (aq) → ClO3- (aq) + ClO2- (aq) + H2O (1)
a) Using the method of initial rates what is the order of the reaction with respect to ClO2? (5 points)
) Using the method of initial rates what is the order of the reaction with respect to OH-? (5 points)
c) Calculate k using experiment 1. (5 points)
2. Chemical Equili
ium Experiment
Using the concentrations found in the experiment for the iron cation and thiocyanate anion determine the Kc for iron (III)
thiocyanate using 1.71mL of iron cation solution and 4.00 mL of thiocyanate anion solution. The abso
ance for this mixture
at 460 nm is XXXXXXXXXXShow your calculations. (10 points)
3. Molar Volume of a Gas Experiment
a) You collected 44.1 mL of hydrogen gas in a eudiometer following the procedure outlined in this experiment. You used
0.0462 grams of magnesium. The collected gas had a temperature of 22.0 °C and a pressure of 753 to
XXXXXXXXXXmm of water
emained in the Eudiometer (height of the water column). Based on this data determine the molar volume of a gas at STP.
The vapor pressure of water at 22.0° C is 19.83 to
. (10 points):
) Calculate the percent e
or of the molar volume based on the known value and the experimental value from part a). (5
points)
4. Beer’s Law
In the Kc experiment and in the Beer’s law experiment we did not determine lmax.
a) What is lmax and why is it needed? Explain in 2-3 sentences. (5 points)
) In the Beer’s law lab you set the colorimeter to read in the green region. What would happen to the abso
ance values if
the wavelength of light if the colorimeter was set to read in the red region (using a red wavelength of light)? How would this
alter the concentration values? Explain in 2-3 sentences. (5 points)
5. Equili
ium and Le Chatielier’s principal
In this experiment you studied the reaction of potassium chromate with hydrochloric acid at equili
ium.
2K2CrO4 + 2HCl ⇌ K2Cr2O7 2− + H2O + 2KCl
a) Which way does the reaction shift in order to reestablish equili
ium if more potassium chromate is added? Explain in one
to two sentences. (2 points)
) What is the purpose of adding sodium hydroxide in this experiment? Explain in one to two sentences. (3 points)
c) Barium nitrate add to this reaction will cause a precipitate to form. Determine what the precipitate is. Which way will the
eaction shift in order to reestablish equili
ium once the barium nitrate is added? Explain in one to two sentences. (5
points)