ACP Chemistry Exam: Chapters 5, 6,& 17
Name: ______Period: ____ Date: ______
This exam is worth 70 points. Only those exams completed in black ink will be graded. The information sheet may have formulas useful for this exam. Good luck!
1) A sample of 0.300 moles of nitrogen occupies 0.600 L. Under the same conditions, what number of moles occupies 1.200 L?
A) 0.600 moles
B) 1.50 moles
C) 0.33 moles
D) 6.00 moles
E) 0.006 moles
2) A large balloon is initially filled to a volume of 25.0 L at 353 K and a pressure of 2575 mm Hg. What volume of gas will the balloon contain at 1.35 atm and 253 K?
A) 22.2 L
B) 87.5 L
C) 11.4 L
D) 45.0 L
E) 58.6 L
3) Calculate the temperature, in K, of 2.20 moles of gas occupying 3.50 L at 3.30 atm.
A) 64.0 K
B) 5.25 K
C) 337 K
D) 28.0 K
E) None of the above.
4) Which of the following gas samples would be most likely to behave ideally under the stated conditions?
A) Ne at STP
B) CO at 200 atm and 25°C
C) SO2 at 2 atm and 0 K
D) N2 at 1 atm and -70°C
E) O2 at 400 atm and 25°C
5) Place the following gases in order of increasing density at STP.
N2 NH3 N2O4 Ar
A) N2O4 < Ar < N2 < NH3
B) Ar < N2O4 < N2 < NH3
C) N2 < Ar < N2O4 < NH3
D) NH3 < N2 < Ar < N2O4
E) Ar < N2 < NH3 < N2O4
6) What volume will 4.91 x 1022 atoms of Ne occupy at STP?
A) 1.10 L
B) 2.00 L
C) 2.24 L
D) 3.11 L
E) 1.83 L
7) A mixture of 0.220 moles CO, 0.350 moles H2 and 0.640 moles He has a total pressure of 2.95 atm. What is the pressure of H2?
A) 1.17 atm
B) 0.853 atm
C) 1.03 atm
D) 0.969 atm
E) 0.649 atm
8) A gas mixture consists of N2, O2, and Ne, where the mole fraction of N2 is 0.55 and the mole fraction of Ne is 0.25. If the mixture is at STP in a 5.0 L container, how many molecules of O2 are present?
A) 4.5 × 1022 molecules O2
B) 2.7 × 1022 molecules O2
C) 3.7 × 1023 molecules O2
D) 1.1 × 1023 molecules O2
E) 9.3 × 1024 molecules O2
9) Determine the mass of water formed when 12.5 L NH3 (at 298 K and 1.50 atm) is reacted with 18.9 L of O2 (at 323 K and 1.1 atm).
4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g)
A) 17.0 g H2O
B) 20.7 g H2O
C) 37.7 g H2O
D) 13.8 g H2O
E) 27.9 g H2O
10) Rank the following in order of decreasing rate of effusion.
F2 SF6 CO Kr
A) SF6 > Kr > F2 > CO
B) Kr > CO > SF6 > F2
C) F2 > Kr > CO > SF6
D) CO > F2 > Kr > SF6
E) CO > F2 > SF6 > Kr
11) Which of the following statements is TRUE?
A) Particles of different masses have the same average speed at a given temperature.
B) The larger a molecule, the faster it will effuse.
C) At very high pressures, a gas will occupy a larger volume than predicted by the ideal gas law.
D) For a given gas, the lower the temperature, the faster it will effuse.
E) None of the above statements are true.
12) Which of the following is TRUE if ΔEsys = - 95 J?
A) The system is gaining 95 J, while the surroundings are losing 95 J.
B) The system is losing 95 J, while the surroundings are gaining 95 J.
C) Both the system and the surroundings are gaining 95 J.
D) Both the system and the surroundings are losing 95 J.
E) None of the above are true.
13) Define molar heat capacity.
A) the quantity of heat required to raise the temperature of 1 mole of a substance by 1°C
B) the quantity of heat required to change a system's temperature by 1°C
C) the quantity of heat required to raise the temperature of 1 gram of a substance by 1°C
D) the quantity of heat required to raise the temperature of 1 g of a substance by 1°F
E) the quantity of heat required to raise the temperature of 1 liter of a substance by 1°C
14) Which of the following substances (with specific heat capacity provided) would show the greatest temperature change upon absorbing 100.0 J of heat?
A) 10.0 g Ag, CAg = 0.235 J/g°C
B) 10.0 g H2O, CH2O = 4.18 J/g°C
C) 10.0 g ethanol, Cethanol = 2.42 J/g°C
D) 10.0 g Fe, CFe = 0.449 J/g°C
E) 10.0 g Au, CAu = 0.128 J/g°C
15) Calculate the amount of heat (in kJ) necessary to raise the temperature of 47.8 g benzene by 57.0 K. The specific heat capacity of benzene is 1.05 J/g°C
A) 1.61 kJ
B) 16.6 kJ
C) 2.59 kJ
D) 2.86 kJ
E) 3.85 kJ
16) A balloon is inflated from 0.0100 L to 0.500 L against an external pressure of 10.00 atm. How much work is done in joules? 101.3 J = 1 L x atm
A) -49.6 J
B) 49.6 J
C) 0.49 J
D) -0.49 J
E) -496 J
17) Which statement is FALSE?
A) An exothermic reaction gives heat off heat to the surroundings.
B) Enthalpy is the sum of a system's internal energy and the product of pressure and volume.
C) ΔErxn is a measure of heat.
D) ΔHrxn is the heat of reaction.
E) Endothermic has a positive ΔH.
18) How much energy is required to decompose 765 g of PCl3, according to the reaction below? The molar mass of PCl3 is 137.32 g/mol and may be useful.
4 PCl3(g) → P4(s) + 6 Cl2(g) ΔH°rxn = +1207 kJ
A) 2.31 × 103 kJ
B) 4.33 × 103 kJ
C) 6.72 × 103 kJ
D) 1.68 × 103 kJ
E) 5.95 × 103 kJ
19) Two aqueous solutions are both at room temperature and are then mixed in a coffee cup calorimeter. The reaction causes the temperature of the resulting solution to fall below room temperature. Which of the following statements is TRUE?
A) The products have a lower potential energy than the reactants.
B) This type of experiment will provide data to calculate ΔErxn.
C) The reaction is exothermic.
D) Energy is leaving the system during reaction.
E) None of the above statements are true.
20) A 100.0 mL sample of 0.300 M NaOH is mixed with a 100.0 mL sample of 0.300 M HNO3 in a coffee cup calorimeter. If both solutions were initially at 35.00°C and the temperature of the resulting solution was recorded as 37.00°C, determine the ΔH°rxn (in units of kJ/mol NaOH) for the neutralization reaction between aqueous NaOH and HCl. Assume 1) that no heat is lost to the calorimeter or the surroundings, and 2) that the density and the heat capacity of the resulting solution are the same as water (1.00 g/mL).
A) -55.7 kJ/mol NaOH
B) -169 kJ/mol NaOH
C) -16.7 kJ/mol NaOH
D) -27.9 kJ/mol NaOH
E) - 34.4 kJ/mol NaOH
21) Use the standard reaction enthalpies given below to determine ΔH°rxn for the following reaction:
P4(g) + 10 Cl2(g) → 4PCl5(s) ΔH°rxn = ?
Given:
PCl5(s) → PCl3(g) + Cl2(g) ΔH°rxn= +157 kJ
P4(g) + 6 Cl2(g) → 4 PCl3(g) ΔH°rxn = -1207 kJ
A) -1835 kJ
B) -1364 kJ
C) -1050. kJ
D) -1786 kJ
E) -2100. kJ
22) Which of the following processes have a ΔS > 0?
A) CH3OH(l) → CH3OH(s)
B) N2(g) + 3 H2(g) → 2 NH3(g)
C) CH4(g) + H2O (g) → CO(g) + 3 H2(g)
D) Na2CO3(s) + H2O(g) + CO2(g) → 2 NaHCO3(s)
E) All of the above processes have a ΔS > 0.
23) Consider the following reaction at constant P. Use the information here to determine the value of ΔSsurr at 298 K. Predict whether or not this reaction will be spontaneous at this temperature.
N2(g) + 2 O2(g) → 2 NO2(g) ΔH = +66.4 kJ
A) ΔSsurr = +223 J/K, reaction is spontaneous
B) ΔSsurr = -223 J/K, reaction is not spontaneous
C) ΔSsurr = -66.4 J/K, reaction is spontaneous
D) ΔSsurr = +66.4 kJ/K, reaction is not spontaneous
E) ΔSsurr = -66.4 J/K, it is not possible to predict the spontaneity of this reaction without more information.
24) Which of the following relationships is correct at constant T and P?
A) ΔG is proportional to -ΔSuniv
B) ΔG > 0 represents a spontaneous process
C) ΔG > 0 represents an increase in kinetic energy
D) ΔG < 0 represents a nonspontaneous process
E) All of the above are correct
25) Consider a reaction that has a positive ΔH and a positive ΔS. Which of the following statements is TRUE?
A) This reaction will be spontaneous only at low temperatures.
B) This reaction will be spontaneous at all temperatures.
C) This reaction will be nonspontaneous at all temperatures.
D) This reaction will be nonspontaneous only at low temperatures.
E) It is not possible to determine without more information.
26) For the following example, identify the following.
2 N2O (g) → 2 N2(g) + O2(g)
A) a negative ΔH and a negative ΔS
B) a positive ΔH and a negative ΔS
C) a negative ΔH and a positive ΔS
D) a positive ΔH and a positive ΔS
E) It is not possible to determine without more information.
27) Above what temperature does the following reaction become nonspontaneous?
FeO(s) + CO(g) → CO2(g) + Fe(s) ΔH = -11.0 kJ; ΔS = -17.4 J/K
A) 632 K
B) 298 K
C) 191 K
D) This reaction is nonspontaneous at all temperatures.
E) This reaction is spontaneous at all temperatures.
28) Place the following in order of increasing entropy at 298 K.
Ne Xe He Ar Kr
A) He < Kr < Ne < Ar < Xe
B) Xe < Kr < Ar < Ne < He
C) Ar < He < Ar < Ne < Kr
D) Ar < Ne < Xe < Kr < He
E) He < Ne < Ar < Kr < Xe
29) Place the following in order of increasing standard molar entropy.
H2O (l) H2O (g) H2O (s)
A) H2O (g) < H2O (l) < H2O (s)
B) H2O (s) < H2O (l) < H2O (g)
C) H2O (g) < H2O (s) < H2O (l)
D) H2O (l) < H2O (s) < H2O (g)
E) H2O (s) < H2O (g) < H2O (l)
30) Place the following in order of decreasing standard molar entropy.
NaCl(s) Na3PO4 (aq) NaCl (aq)
A) NaCl(s) > NaCl (aq) > Na3PO4 (aq)
B) NaCl (aq) > NaCl(s) > Na3PO4 (aq)
C) Na3PO4 (aq) > NaCl (aq) > NaCl(s)
D) NaCl(s) > Na3PO4 (aq) > NaCl (aq)
E) NaCl (aq) > Na3PO4 (aq) > NaCl(s)
31) Calculate ΔS°rxn for the following reaction. The S° for each species is shown below the reaction.
C2H2(g) + H2(g) → C2H4(g)
S°(J/mol∙K) 200.9 130.7 219.3
A) +112.3 J/K
B) +550.9 J/K
C) -112.3 J/K
D) +337.1 J/K
E) -550.9 J/K
32) Give the name of the reaction that achieves the theoretical limits with respect to free energy in thermodynamics.
A) reversible reaction
B) forward reaction
C) reverse reaction
D) equilibrium reaction
E) irreversible reaction
33) Estimate ΔG°rxn for the following reaction at 449.0 K.
CH2O(g) + 2 H2(g) → CH4(g) + H2O(g) ΔH°= -94.9 kJ; ΔS°=
-224.2 J/K
A) +5.8 kJ
B) +12.9 kJ
C) -101 kJ
D) +2.4 kJ
E) -4.2 kJ
34) Calculate ΔGrxn at 298 K under the conditions shown below for the following reaction.
2 Hg(g) + O2(g) → 2 HgO(s) ΔG° = -180.8 kJ
P(Hg) = 0.025 atm, P(O2) = 0.037 atm
A) +207 kJ
B) -154.4 kJ
C) -26.5 kJ
D) -164 kJ
E) +60.7 kJ
35) Choose the statement below that is TRUE.
A) K > 1, ΔG°rxn is positive.
B) K < 1, ΔG°rxn is negative.
C) ΔG°rxn = 0 at equilibrium.
D) ΔGrxn = 0 at equilibrium.
E) None of the above statements are true.
9