Quiz 4 – Potential Energy Diagrams
1. The addition of a catalyst to a reaction provides an alternative mechanism with
A. Lower activation energy and lower reaction rate
B. Lower activation energy and higher reaction rate
C. Higher activation energy and lower reaction rate
D. Higher activation energy and higher reaction rate
2. Consider the following Reaction
½ N2(g) + ½ O2(g) ------- > NO(g)
∆H = +90 kJ/mol NO
The correct equation including the heat term is
A. N2(g) + O2(g) +90 kJ ------- > 2NO(g)
B. N2(g) + O2(g) +180 kJ ------- > 2NO(g)
C. N2(g) + O2(g) ------- > 2NO(g) +90kJ
D. N2(g) + O2(g) ------- > 2NO(g) +180kJ
3. A forward reaction has an activation energy of 50 kJ and a ∆H of –100 kJ.
The PE diagram, which describes this reaction, is
A.
4. Consider the following potential energy diagram
The Activation energy for the forward reaction is
A. 25 kJ
B. 50 kJ
C. 75 kJ
D. 125 kJ
5. Consider the following reaction
½ H2(g) + ½ I2(g) ------- > HI(g)
The activation energy for the formation oh HI is 167 kJ and for the decomposition of
HI is 139 kJ
The reaction for the formation of HI is
A. Exothermic and the ∆H = -28 kJ
B. Exothermic and the ∆H = +28 kJ
C. Endothermic and the ∆H = -28 kJ
D. Endothermic and the ∆H = +28 kJ
6. Consider the following potential energy diagram
The energy interval the represents the activation energy for the reverse reaction is
A. I
B. II
C. III
D. IV
7. As reactant molecules approach each other
A. Heat is released
B. A reaction intermediate forms
C. Kinetic energy changes to potential energy
D. Potential energy changes to kinetic
8. Which of the following equations represents an endothermic reaction?
A. N204(g) + 59 kJ ------- > 2NO2(g)
B. 2H2(g) + 02(g) ------- > 2H2O(l) + 572 kJ
C. 2BrCl(g) – 29.3 kJ ------ > Br2(g) + Cl2(g)
D. C(s) + O2(g) ------- > CO2(g) ∆H = -394 kJ
9. Consider the following potential energy diagram
The interval representing ∆H for the reverse reaction is
A. 1
B. 2
C. 3
D. 4
10. Which of the following corresponds to the fastest reaction at room temperature
11. When a catalyst is added to a reaction, ∆H will
A. Increase slowly
B. Remain constant
C. Decrease slowly
D. Increase rapidly due to alternate pathway
12. Consider the following potential energy diagram that represents two different
reactions
Which of the following statements is correct?
A. Reactions A and B are both exothermic
B. Reactions A and B are both endothermic
C. Reaction A is exothermic and reaction B is endothermic
D. Reaction A in endothermic and reaction B is exothermic
13. Consider the following reaction
½ H2(g) + ½ I2(g) ------- > HI(g)
∆H = +28 kJ
The activation energy for the formation of HI is 167 kJ. the activation energy for the
decomposition of HI is
A. 28 kJ
B. 139 kJ
C. 167 kJ
D. 195 kJ