Gas Laws/Thermochemistry Bonus Quiz
10/28/13
Name
Directions: This quiz will serve exclusively as a bonus quiz. To qualify for the bonus points, you
must score at least a 70%. I will add 12.5% of your total score on this quiz to your highest exam
score. If your preference is to replace your lowest quiz score with this quiz, write the word
“QUIZ” in the top right-hand corner of this sheet. Make sure to reach each question thoroughly.
Show all work where applicable.
1. A sample of an ideal gas is trapped in a glass tube with a movable plug. The gas has an initial
volume of V1, and an initial pressure of P1, at a constant temperature. Then, the pressure of the gas
is increased by 50%, yielding a new pressure P2. What is V2 (in terms of V1)?
a.) 1.50 V1
b.) .667 V1
c.) 0.50 V
d.) V1
e.) can not determine
2. An ideal gas occupies a volume of 1.3 L at an initial temperature of 35oC. If the gas is heated to
70oC, what will the new volume of the gas be?
a.) no change
b.) 2.6 L
d.) 1.45 L
e.) 1.17 L
c.) 36.3 L
3. A certain gas is contained within a cylinder. The gas is compressed under a constant pressure of
1 atm, resulting in a change in volume of 10 L. Which of the following is true?
a.) wsys = +10.0 J
b.) wsys = +507.7 J
d.) wsys = -10.0 J
e.) wsys = -1013.3 J
c.) wsys = +1013.3 J
4. The change in internal energy of a certain system is +2 kJ. The system performs 400 J of work.
Which is true?
a.) qsys = + 402 J, endothermic
d.) qsys = 1600, endothermic
b.) qsys= -402, exothermic
e.) qsys = -398 J, exothermic
c.) qsys = +2400 J, endothermic
5. A certain system undergoes an endothermic process resulting in the transfer of 300 J of heat.
The system has 250 J of work performed on it. Select all true statements below.
a.) wsurr = +250 J
b.) ΔUsurr = -550 J
d.) wsys = -250 J
e.) ΔUsys = +550 J
c.) qsys = -300 J
6. Which of the following have enthalpies of formation (ΔHoF ) equal to zero? Select all that apply.
a.) Na(s)
c.) Al (L)
e.) He(g)
b.) CO2(g)
d. ) H2O (L)
f.) Cl2 (g)
7. If a system possesses 100 kJ of internal energy, is it possible to perform 100 kJ of work? Explain.
8. From the following heats of reaction:
4N2(g) + 2O2(g)  4N2O(g)
∆𝐻1𝑜 = -400.0 kJ/mol
6O2(g)  4O3 (g)
∆𝐻2𝑜 = +300.0 kJ/mol
Use Hess’s Law to calculate the enthalpy of reaction for: 3N2(g) + O3(g)  3N2O(g)
9. In the reaction below, 5g of calcium carbonate are added to 285 mL of 1.97 M hydrobromic acid
at standard temperature and pressure. The reaction proceeds with 84% yield. Determine the
volume of the gas formed. Use R = 0.0821 L atm mol-1 K-1.
CaCO3 (s) + HBr (aq)  CaBr2 (aq) + CO2 (g) + H2O (L)
BONUS: Use bond enthalpies to determine the enthalpy of reaction
for the combustion of C3H8.
Equations
PV = nRT
Boyle’s: V α 1/P
ΔU = q + w
w = -PΔV
Charles’s: V α T
101.325 J = 1 L atm