CHM 152 1st Edition Exam #1 Study GuidePractice Exam 1A1. Which of the following elements has the largest entropy at room temperature? [a] Sn(s) [b] Hg(l) [c] N2(g) [d] Cl2(g) [e] C(s)2. Which of the following reactions would have the largest increase in entropy? [a] H O (l) → H O (s) [b]NaNO3(s) → Na+ (aq)+ NO−(aq)2 23[c]2 HCl (g) → H2 (g) + Cl2 (g)[d]2 H2 (g) + O2 (g) → 2H2O (g)3. If a reaction is said to be spontaneous, then we absolutely know that: [a] the G of the reaction must be greater than zero. [b] the reaction occurs at a fast rate. [c] the reaction gives off heat. [d] the reaction, once started, will proceed without outside intervention. [e] Two of the above are correct. 4. "A spontaneous change is always accompanied by an increase in entropy." The entropy change referred to inthis statement is: [a]Suniverse[b]Ssystem[c]Sreversible[d]Ssurroundings[e]Scalvin5.If G° < 0 for a reaction at all temperatures, then H° is _________ and S° is _________ .[a] negative, positive [b]positive, negative[c]negative, negative[d] positive, positive [e] positive, either positive or negative6.If H of a system is exothermic, then S of the surroundings _______________ .[a] decreases [b] increases [c] is zero [d] remains the sameThe next two questions refer to the following reactionCO (g) + 2 H2 (g) → CH3OH (g)for which the following data are available.Compound H° (kJ/mol) S° (J/mol⋅K)CO (g) −110.5197.5H2 (g)130.6CH3OH (g)−200.7239.77.What is the value ofS° for this reaction?[a] −219.0 J/K [b] −164.1 J/K [c] −88.4 J/K [d] 88.4 J/K [e] 219.0 J/K8.What is G° for this reaction at 25°C?[a] −155.4 kJ [b] −24.9 kJ [c] +24.9 kJ [d] +155.4 kJ [e] none of these9. For the following reaction at 25°C, 2 H2O2 (l) → 2 H2O (l) + O2 (g)calculate Suniv°givenSsys° = 125.8 J/K andHsys° = − 196.1 kJ .[a] −783.9 J/K [b] −531.9 J/K [c] +494.2 J/K [d] +783.9 J/K[e] +3741 J/K10.Predict the signs of the standard free energy, the standard enthalpy, and the standard entropy changes forthe following process at 20°C. H2O (s) → H2O (l)G° H° S°[a]− −+[b]−+ +[c] +− −[d]−+−[e] + + +11. For the following reaction, Hsys° = + 20.2 kJ and Ssys° = − 43.1 J/K . Which of the following statements about this reaction is true?H2S (g) → H2 (g) + S (s)[a] the reaction is not spontaneous. [b] the reaction is always spontaneous. [c] the reaction will become spontaneous at higher temperatures. [d] the reaction will become nonspontaneous at higher temperatures. [e] impossible to determine from the information given. 12. At what temperatures will a reaction be spontaneous ifH = +158 kJ and S = +411 J/K?[a] All temperatures below 384 K [b] All temperatures above 384 K[c] The reaction is spontaneous at any temperature [d]The reaction will never be spontaneous[e] Temperatures between 158 K and 411 K 13.Correct units of "reaction rate" are: [a] L mol−1 s−1[b] L2 mol−2 s−1[c] s−1[d] s−2[e] mol L−1 s−114.For the following reaction, the rate of appearance of Br2 is 0.30 moles/L⋅s. 2 NO2Br → 2 NO2 + Br2What is the rate of disappearance of NO2Br?[a] 0.15 moles/L⋅s [b] 0.60 moles/L⋅s [c] 0.45 moles/L⋅s[d] 0.10 moles/L⋅s [e] none of these15. A particular reaction has the following units for the rate constant, K:1. What is the order of the reaction?3M⋅ s[a]4th[b] 1st[c]2nd[d] 3rd[e]not enough informationto determine16.Which one of the following would alter the value of the rate constant (K) for the reaction: 2 A + B →products? [a] increasing the concentration of A. [b] increasing the concentration of B. [c] increasing the temperature. [d] measuring k again after the reaction had run for a while. [e] none of these would alter the rate constant. 17.Consider the reaction, A → B. The rate of the reaction is 3.2 × 10−2 M/s when the concentration of A is0.70 M. Calculate the value of the rate constant, K, assuming the reaction is second-order. [a]k = 6.5 × 10−2M−1s−1[b] k = 3.2 × 10−2 M−1s−1[c] k = 15 M−1s−1[d] k = 4.6 × 10−2 M−1s−1[e] k = 1.6 × 10−2 M−1s−118.The rate law for the following reaction is: Rate = k[A][B]. The reaction rate will change if _____________? 2 A + B → products[a] the concentration of A is increased. [b] the concentration of B is decreased. [c] the temperature is decreased. [d] the rate is measured again after the reaction has run for a while. [e] All of these would alter the rate. 19. The reaction A + 2 B → products, was found to have the rate law, Rate = k[A][B]3. Predict by what factor therate of reaction will increase when the concentration of A is tripled and the concentration of B is doubled. [a] 6 [b] 18 [c] 24 [d] 48 [e] none of theseThe reaction2 ClO2 (g) + 2 OH− (aq) → ClO3− (aq) + ClO2− (aq) + H2O (l)was studied at 25°C, and the following data were obtained:Expt #[ClO2]0 (M)[OH−]0 (M)Initial Rate (M/s)10.060 0.0300.024820.020 0.030 0.0027630.020 0.090 0.0082820.What is the rate law for this reaction? [a]Rate = k[ClO2]2[OH−][b]Rate = k[ClO2][OH−]2[c] Rate = k[ClO2][OH−][d]Rate = k[ClO2]2[e] none of these21.Calculate the rate constant, K, for this reaction. Use data from Experiment 3. [a]3.0 × 10−7 M−2s−1[b]51 M−2s−1[c] 4.6M−2s−1[d]230 M−2s−1[e] none of these22.If [ClO2] = 0.010 M and [OH−] = 0.020 M, what is the rate of the reaction? [a] 4.0 × 10−6 M/s [b] 4.6 × 10−4 M/s [c] 4.6 × 10−2 M/s [d] 1.2 × 108 M/s [e] none of these23.Which factors can affect the rate of a reaction? I. concentration of reactant II. temperatureIII. frequency of reactant collisionsIV. activation energy V. orientation of reactant collision[a] I only [b] II only [c] I, II, III [d] II, III, IV, and V [e] All of these24.Below is a plot of lnk versus 1/T for the reaction 2 N2O5 (g) → 2 N2O4 (g) + O2 (g)-6.0-7.0ln k vs 1/T-8.0-9.0-10.0Y = -12392X + 30.629-11.00.00290 0.00300 0.00310 0.00320 0.00330 0.00340Based on this information, the activation energy, Ea, for this reaction is:[a] 12.5 kJ/mol [b] 1500 kJ/mol [c] 1500 J/mol[d] 104 J/mol [e] 104 kJ/mol25.The rate constant for the acid hydrolysis of sucrose (cane sugar) is 2.12 × 10−4 M−1s−1 at 27°C. If Ea = 107kJ/mol for this reaction, what is the value of the rate constant at 37°C? [a]2.24 × 10−4 M−1s−1[b]8.46 × 10−4 M−1s−1[c] 1.34