Physical Chemistry Mock Midterm Exam

Physical Chemistry Mock Midterm Exam

**disclaimer: I have no idea exactly what will be on the midterm exam beyond what was listed by the professor in class, although I do know these section headings are accurate. This mock midterm is written only as a study tool. It’s usefulness is debatable.

Part I: Definitions (20%)

Provide definitions for each of the following terms. Do NOT give any examples of the terms or you will lose marks.  (1 mark per definition, -1 mark if example given)

1) System:

2) Isolated system:

3) closed system:

4) open system:

5) surroundings:

6) Zeroth Law of Thermodynamics:

7) Thermal Energy:

8) Internal Energy:

9) Heat:

10) Work:

11) First Law of Thermodynamics:

12) Reversible Path:

13) Nonreversible Path:

14) State Function:

15) Heat Capacity (also include definition for molar heat capacity and specific heat capacity):

16) Translational State (strongly doubt this would actually be asked because not defined in lecture):

17) Rotational State:

18) Vibrational State:

19) Equiparition of Energy:

20) Bond Energy

21) Hess’s Law:

22) Heat of Formation of a Molecule:

22) Heat of Combustion of a Molecule:

23) Enthalpy:

26) State: 

Part II: Calculations

Provide all work, including appropriate equations, notation, and manipulation.

Try (or retry) calculations from the textbook without looking at the solutions manual.

For a good selection of questions do:

Energy, Heat, Work

3, 4, 6, 10

Thermochemistry

15, 17, 21, 24, 29, 32, 34

Equiparitioning of Energy

1)   Calculate the number of degrees of freedom for carbon dioxide. Estimate the molar heat capacity of the substance.

2)   Calculate the number of degrees of freedom for methane. Estimate the molar heat capacity of the substance.

Part III: Short Answers

1)   What type of system is a coffee cup calorimeter? What type of system is a bomb calorimeter? Compare and contrast.

2)   If system A is 25ºC and system B is 25ºC, and system C is in equilibrium with system B, what can we conclude about the temperature of system C and its relationship with system A?

3)   Draw potential energy diagram of a diatomic molecule. Label the place of greatest repulsion, A. Label the place of greatest stability, B. Label zero point, C. Label and show the bond energy. Draw in the largest state (rotational/vibrational/translational) , and discuss the placement and magnitude of the other states (rotational/vibrational/translational).

4)   Is the maximum work done by the system reversible or irreversible? Explain referring to a P versus V diagram.

5)   Using the definition of enthalpy, show that it is equal to the heat at constant pressure.

6)   Define both the heat capacity at constant volume and the heat capacity at constant pressure.

7)   Is work a state function? Explain.

8)   Discuss how differential calorimetry finds the unknown heat capacity of a substance.

9)   What is the standard enthalpy of formation of oxygen gas?

10) Why is the bond energy always positive?

11) Hydrogen gas only has 2 rotational degrees of freedom. Explain why.

12) Discuss the effects of temperature when comparing calculated heat capacities using equiparitioning of energy and the actual measured heat capacity values.

Part IV: True or False

This section will NOT be on the exam, however, it may provide a good snapshot as to whether the definitions are understood.

1)   Heat leaves the system. q is positive.             True/False

2)   Energy is stored in chemical bonds.             True/false 

3)   The system does work. w is negative.             True/false

4)   Internal energy does not depend on PV work.             True/false

5)   Bond energy is usually greater than thermal energy.             True/false

6)   A diatomic gas has 2 degrees of translational energy.             True/false

7)   PV work is positive for an expansion of a gas.             True/false 

8)   The lowest vibrational state is at the zero point.             True/false 

9)   The heat capacity at a phase change is infinite.            True/false

10)  Vibrational states are the same as angular momentum.             True/false 

Part V: Bonus Questions

1)   Show that PV=nRT is a state function using partial derivatives and Euler’s Theorem for Exactness without referring to Appendix C. (Just kidding! Bad joke, I know.) (Yes, I am actually joking about this one, don't try to solve it!)

2)   Describe your experience and opinion of the textbook with regards to whether you have the e-book or hardcopy, its acquisition and availability, its use as a study tool, and to what extent it corresponds to and complements the lectures.