CHM 152L Review Outline for Final Exam Given During Reading Week

A review session should take place the week before the final exam is scheduled. The final exam will be given the week before reading week for most lab sections. Only a calculator and pencil may be used to take the exam along with the final exam, scratch paper, and formula sheet provided. You may write on the final exam.

The formula sheet (click on link to examine sheet) should contain any key formulas need to finish the exam.

Summary of Experiments

Calculation of formula weight (molar mass) from chemical formula using chemical formula

Conversion between grams and moles of a compound using formula weight (molar mass)

Conversion between moles and volume of a solution using molarity

Calculation of mean, median, range, error, and percent error

Be able to evaluate data to using the above mentioned values

Preparation of solution by quantitative dilution: M1V1=M2V2

Heat Capacity (determining temp. change from graph)

Enthalpy of Reaction

Enthalpy of Formation

Wavelength versus absorbance plot

Rate

Order of Reaction

Conditions affecting enzymes

Percent Weight

Empirical Formula

Theoretical and % yield

Use charge balance, empirical formula calculations, and range to evaluate data

Serial Dilutions

 

Use of Standard Curve

Finding Final Concentrations (from graph)

Equilibrium

y=mx+b

End point

Equivalence point

Moles at equivalent point (from graph)

Equivalent weight

pKa = pH (at 50% titration point)

Reduce Vs. Oxidize

Molarity and  Percent by Mass

Using a primary standard to standardize a  solution

Stoichiometry

 

General Guidelines

  1. You should be familiar with the objectives of each experiment.
  2. You should be able to complete all calculations given the formula and units.
  3. You should be familiar with all of the graphs and what can be determined from them and how that information can be used to complete a calculation.
  4. Remember that significant figures are important.
  5. Looking over quizzes given through out the semester can be a good place to start your review.
  6. Pre and post lab questions may appear on the final.
  7. Remember that any equation you need, will be given and if it is not supplied then ask your TA for the information you need.


 
 

CHM 152L Final Exam Practice Quiz

1. Why is it important to use a constant volume of solution throughout experiment A?
          a) Because heat is lost to the surroundings
          b) To keep the Cp. value constant
          c) Because the reaction involves metal oxides.
          d) Because the reaction is endothermic.
          e) None of the above

2. Why does one extrapolate back to the time the reactants were mixed to find Tf in experiment A?
          a) Because heat is lost to the surroundings
          b) To keep the Cp value constant
          c) Because the reaction involves metal oxides.
          d) Because the reaction is endothermic.
          e) None of the above

3. Calculate the simplest empirical formula for CxHy if C=12.0g and H=3.0g in a total sample mass of 15.0g?
          a) C2H10
          b) C16H
          c) CH3
          d) None of the above

4. In experiment B, what is the order of reaction with respect to the substrate  if the slope of the graph (time versus absorbance) does not change when the substrate concentration is doubled? (Assume the enzyme concentration is constant.)
           a) zero
           b) first
           c) second
           d) third
           e) None of the above

5. What is a primary standard is used for?
           a) To find the equilibrium.
           b) To find out if the solution is an acid or a base.
           c) To find the concentration of another solution.
           d) To find the Cp of an Acid-Base reaction.
           e) None of the above.

6. In experiment B it is important to know the absorbance at  the  wavelength for the absorabance maximum of the product (p-nitroaniline) because:
           a) it can be related to enzyme concentration and so rate of reaction
           b) it can be related to solvent concentration and so rate of reaction
           c) it can be related to substrate concentration and so rate of reaction
           d) it can be related to buffer concentration and so rate of reaction
           e) None of the above

7. Calculate the initial molarity if 5.00 mL of NaOH was diluted to 0.0200M NaOH with a total volume of 100.00mL?
           a) 0.000100M
           b) 0.400M
           c) 0.0400M
           d) 0.0100M
           e) None of the above.

8. What are the final or equilibrium concentrations for the following reaction Fe3+ + SCN-=FeSCN2+. The initial concentrations are [Fe3+]=2.50x10-4M and [SCN-]=1.5x10-4M and the final or equilibrium concentration of [FeSCN2+]=1.00x10-5.
           a) [Fe3+]=2.50x10-4 [SCN-]=1.5x10-4 [FeSCN2+]=1.00x10-5.
           b) [Fe3+]=2.4x10-4 [SCN-]=1.4x10-4 [FeSCN2+]=1.00x10-5.
           c) [Fe3+]=1.5x10-4 [SCN-]=5.0x10-3 [FeSCN2+]=1.00x10-5.
           d) [Fe3+]=5.0x10-3[SCN-]=1.5x10-4 [FeSCN2+]=-1.4x10-4.
           e) None of the above.

9. What is the equilibrium constant (Kc) for Fe3+ + SCN- FeSCN2+ using the above problem?
           a) 266.67
           b) 297.62
           c) 13.33
           d) -186.67
           e) None of the above.

10. At what point is the pKa equal to the pH?
           a) At the equivalent point.
           b) At 100% T.
           c) At the 50%T point.
           d) At the point when all of the acid is base.
           e) None of the above.

11. What is the pKa for graph E2 on page E-4 in your lab manual?
           a) 6.2
           b) 2.8
           c) 8.7
           d) 4.5
           e) 12.8

12. If you titrate 0.150g of an iron salt with 0.199M NaOH what would the % Fe be using figure E6 on page E-16?
           a) 53.3%
           b) 17.8%
           c) 35.6%
           d) 0.356%
           e) 0.18%

13. What is the molarity (M or mol/L) if 2.278 g of Na2C2O4 are in 100.00mL?
           a) 0.2278M
           b) 0.02278M
           c) 0.8500M
           d) 0.1700M
           e) 0.134M

14. Calculate the enthalpy of reaction in kJ/mol if Cp=0.220kJ/C and 1.23g of MgO reacted with excess HCl, causing a temperature change of 15.0 degrees C.
           a) 108.2
           b) 1082.0
           c) -1082.0
           d) -108.2
           e)  -3.3
 

Answers:
1. b
2. a
3. c
4. a
5. c
6. c
7. b
8. b
9. b
10. c
11. d
12. b
13. d
14. d