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30 Cards in this Set
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The first law of thermodynamics can be given as _______. a. ∆E = q + w b. ∆H° rxn= ƩnH°f (products) - ƩmH°f(reactants) d. the entropy of a pure crystalline substance at absolute zero is zero e. ∆S = qrev/T at constant tempereature |
a. ∆E = q + w
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A reaction that is spontaneous as written ______ . a. is very rapid b. will proceed without outside intervention c. is also spontaneous in the reverse direction d. has an equilibrium position that lies far to the left e. is very slow |
b. will proceed without outside intervention
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Of the following, only ______ is not a state function. a. S b. H c. q d. E e. T |
c. q
state functions are in capital letter |
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When a system is at equilibrium, ______. a. the reverse process is spontaneous but the forward process is not b. the forward and the reverse processes are both spontaneous c. the forward process is spontaneous but the reverse process is not d. the process is not spontaneous in either direction e. both forward and reverse processes have stopped |
d. the process is not spontaneous in either direction
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A reversible process is one that ________. a. can be reversed with no net change in either system or surrounding b. happens spontaneously c. is spontaneous in both directions d. must be carried out at low temperatures e. must be carried out at high temperatures |
a. can be reversed with no net change in either system or surrounding
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The thermodynamic quantity that expresses the degree of disorder in a system is _______. a. enthalpy b. internal energy c. bond energy d. entropy e. heat flow |
d. entropy
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For an isothermal process, ∆S = __________. a. q b. qrev/T c. qrev d. Tqrev e. q + w |
b. qrev/T
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Which one of the following is always positive when a spontaneous process occurs? a. ∆Ssystem b. ∆Ssurroundings c. ∆Suniverse d. ∆Huniverse e. ∆Hsurroundings |
c. ∆Suniverse
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The entropy of the universe is ______. a. constant b. continually decreasing c. continually increasing d. zero e. the same as the enrgy, E |
c. continually increasing
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A system that doesn't exchange matter or energy with its surroundings is called an ______. a. adiabatic b. isolated c. isothermal d. isobaric e. isotonic |
b. isolated
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The second law of thermodynamics states that _______. a. ∆E = q + w b. ∆H° rxn= ƩnH°f (products) - ƩmH°f(reactants) c. for any spontaneous process, the entropy of the universe increases d. the entropy of a pure crystalline substance is zero at absolute zero e. ∆S = qrev/T at constant tempereature |
c. for any spontaneous process, the entropy of the universe increases
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∆S is positive for the reaction _______.
a. 2H2 (g) + O2 (g) --> 2H2O (g) b. 2NO2 (g) --> N2O4 (g) c. CO2 (g) --> CO2 (s) d. BaF2 (s) --> Ba2+ (aq) + 2F- (aq) e. 2Hg (l) + O2 (g) --> 2HgO (s) |
d. BaF2 (s) --> Ba2+ (aq) + 2F- (aq)
goes from solid to aq and there are more atoms on the reactant side |
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Which of the following processes produces a decrease in the entropy of the system? a. boiling water to form steam b. dissolution of solid KCl in water c. mixing of two gases into one container d. freezing water to form ice e. melting ice to form water |
d. freezing water to form ice
decreases entropy because you are forming a solid which has the least amount of disorder |
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∆S is positive for the reaction _______.
a. CaO (s) + CO2 (g) --> CaCO3 (s) b. N2 (g) + 3H2 (g) --> 2NH3 (g) c. 2SO3 (g) --> 2SO2 (g) + O2 (g) d. Ag+ (aq) + Cl- (aq) --> O2 (g) e. H2O (l) --> H2O (s) |
c. 2SO3 (g) --> 2SO2 (g) + O2 (g)
because you are going from 1 mole of reactant to 3 moles of product which is a higher entropy so it is positive |
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Which reaction produces a decrease in the entropy of the system? a. CaCO3 (s) --> CaO (s) + CO2 (g) b. 2C (s) + O2 (g) --> 2CO (g) c. CO2 (s) --> CO2 (g) d. 2H2 (g) + O2 (g) --> 2H2O (l) e. H2O (l)j --> H2O (g) |
d. 2H2 (g) + O2 (g) --> 2H2O (l)
because you are going from a gas which has high entropy to a liquid which has lower entropy |
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Which reaction produces an increase in the entropy of the system? a. Ag+ (aq) + Cl- (aq) --> AgCl (s) b. CO2 (s) --> CO2 (g) c. H2 (g) + Cl2 (g) --> 2HCl (g) d. N2 (g) + 3H2 (g) --> 2NH3 (g) e. H2O (l) --> H2O (s) |
b. CO2 (s) --> CO2 (g)
because a. aq to solid = decrease b. solid to gas = increase c 2 gas to 2 gas = neutral d. 4 gas to 2 gas = decrease e. liquid to solid = decrease |
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Which one of the following processes produces a decrease of the entropy of the system? a. dissolving sodium chloride in water b. sublimination of naphthalene c. dissolving oxygen in water d. boiling of alcohol e. explosion of nitroglycerin |
c. dissolving oxygen in water
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∆S is negative for the reaction _______.
a. 2 SO2 (g) + O2 (g) --> 2SO3 (g) b. NH4Cl (s) --> NH3 (g) + HCl (g) c. PbCl2 (s) -->Pb^2+ (aq) + 2Cl- (aq) d. 2C (s) + O2 (g) --> 2CO2 (g) e. H2O (l) --> H2O (g) |
a. 2 SO2 (g) + O2 (g) --> 2SO3 (g)
because a. 3 gas to 2 gas = negative b. solid to gas = positive c. solid to aq = positive d. solid to gas = positive e. liquid to gas = positive |
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Consider a pure crystalline solid that is heated from absolute zero to a temperature above the boiling point of the liquid. Which of the following processes produces the greatest increase in the entropy of the substance? a. melting the solid b. heating the liquid c. heating the gas d. heating the solid e. vaporizing the liquid |
e. vaporizing the liquid
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Which one of the following correctly indicates the relationship between the entropy of a system and the number of different arrangements, W, in the system? a. S = kW b. S = k/W c. S = W/k d. S = k lnW e. S = Wk |
d. S = k lnW
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Of the following, the entropy of _______ is the largest. a. HCl (l) b. HCl (s) c. HCl (g) d. HBr (g) e. HI (g) |
e. HI (g)
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Of the following, the entropy of gaseous ________ is the largest at 25°C and 1 atm. a. H2 b. C2H6 c. C2H2 d. CH4 e. C2H4 |
b. C2H6
it has the most atoms |
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The standard Gibbs free energy of formation of ______ is zero. (a) H2O (l) (b) O (g) (c) H2 (g) a. (a) only b. (b) only c. (c) only d. (b) and (c) e. (a), (b), and (c) |
c. (c) only
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The standard Gibbs free energy of formation of _______ is zero. (a) H2O (l) (b) Na (s) (c) H2 (g) a. (a) only b. (b) only c. (c) only d. (b) and (c) e. (a), (b), and (c) |
d. (b) and (c)
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For the reaction C2H6 (g) --> C2H4 (g) + H2 (g) ∆H° is+137kJ/mol and ∆S° is+120J/K·mol. This reaction is ______ . a. spontaneous at all temperatures b. spontaneous only at high temperatures c. spontaneous only at low temperatures d. non-spontaneous at all temperatures |
b. spontaneous only at high temperatures
∆H° + and ∆S° + is spontaneous only at high temp |
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A reaction that is not spontaneous at low temperature can become spontaneous at high temperature if ∆H is ____ and ∆S is _______. a. +, + b. -, - c. +, - d. -, + e. +, 0 |
a. +, +
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For a reaction to be spontaneous under standard conditions at all temperatures, the signs of ∆H and ∆S must be ____ and _____ respectively. a. +, + b. +, - c. -, + d. -, - e. +, 0 |
c. -, +
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With thermodynamics, one cannot determine _________. a. the speed of a reaction b. the direction of a spontaneous reaction c. the extent of a reaction d. the value of the equilibrium constant e. the temperature at which a reaction will be spontaneous |
a. the speed of a reaction
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If ∆G° for a reaction is greater than zero, then ______. a. K = 0 b. K = 1 c. K > 1 d. K < 1 e. more information is needed |
d. K < 1
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Which one of the following statements is true about the equilibrium constant for a reaction if ∆G° for the reaction is negative? a. K = 0 b. K = 1 c. K > 1 d. K < 1 e. more information is needed |
c. K > 1
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