lee (ml37757) – Ch 5 Thermochemistry – tetzlaff – (201201) This print-out should have 27 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 10.0 points What factor determines whether a reaction will be exothermic or endothermic? 1. the difference in energy between reactants and products 2. the speed of the reaction 3. the relative concentrations of reactants and products in solution 4. the heat properties of the products 1. +350 kJ 5. the activation energy of the reaction 2. −50 kJ 002 10.0 points Refer to the potential energy diagram shown below. 10 350 9
8 7 6 300 5 4 3 2 250 1 0

1

003 10.0 points Refer to the potential energy diagram shown below. 10 550 9
8 7 6 450 5 4 3 2 350 1 0

Energy (kJ)

A

B
0 1 2 3 progress 8 9 101112 rxn 4 5 6 7

What is the change in enthalpy (∆H) for the reaction A → B?

3. −350 kJ 4. −100 kJ 5. +100 kJ

Energy (kJ)

B 004 10.0 points An endothermic reaction corresponds to one in which 1. ∆H is negative; heat is absorbed
0 1 2 3 progress 8 9 101112 rxn 4 5 6 7

A

2. ∆H is positive; heat is absorbed 3. ∆H is negative; heat is evolved 4. ∆H is positive; heat is evolved

What is the change in enthalpy (∆H) for the reaction A → B? 1. −250 kJ 2. −150 kJ 3. +300 kJ 4. +50 kJ 5. −50 kJ

005 10.0 points Which statement would be the best interpretation of the First Law of Thermodynamics? 1. The total amount of energy in the universe is increasing. 2. The total amount of entropy in the universe is increasing.

lee (ml37757) – Ch 5 Thermochemistry – tetzlaff – (201201) 3. The total amount of matter in the universe is constant. 4. The total amount of energy in the universe is constant. 006 10.0 points Consider the reaction 2 H2 (g) + O2 (g) → 2 H2 O(g) at constant pressure. Which response is true for the reaction? 1. No work is done as the reaction