Potential Energy Diagrams Practice
(you do NOT have to print these out. Just record your answers onto
looseleaf).
Q1 a-e
Question
Does the graph represent an endothermic
or exothermic reaction?
Determine the heat of reaction, H, for
this reaction in KJ
Determine the activation energy, Ea for
this reaction in KJ
What is the energy of the activated
complex for this reaction? In KJ
Determine the reverse activation energy,
Ea for this reaction. In KJ
Q2 a-e
Question
Answer
Answer
Does the graph represent an endothermic or
exothermic reaction?
Determine the heat of reaction, H, for this
reaction. In KJ
Determine the activation energy, Ea for this
reaction.in KJ
What is the energy of the activated complex
for this reaction? In KJ
Determine the reverse activation energy, Ea
for this reaction. In KJ
ice 2
Q3.
Exothermic
-20kJ
+60kJ
100kJ
+80kJ Absorbed
Given the balanced equation representing a reaction:
Which statement is true about energy in this reaction?
(1) The reaction is exothermic because it releases heat.
(2) The reaction is exothermic because it absorbs
heat.
(3) The reaction is endothermic because it releases heat. (4) The reaction is endothermic because it absorbs
heat.
Answer-choice 1
>
Q 4. Given the potential energy diagram for a reaction:
Which interval on this diagram represents the difference between the potential energy of the products and the
potential energy of the reactants? (1) 1 (2) 2 (3) 3
(4) 4
Continued next page:
Base your answers to questions 5 and 6 on the information and potential energy diagram below. Chemical cold
packs are often used to reduce swelling after an athletic injury. The diagram represents the potential
energy changes when a cold pack is activated.
5 Which lettered interval on the diagram represents the potential energy of the products?
Answer--> choice D
6. Which lettered interval on the diagram represents the heat of reaction?
Answer-choice C
>
Q 7. A catalyst increases the rate of a chemical reaction by
(1) lowering the activation energy of the reaction (2) lowering the potential energy of the products
(3) raising the temperature of the reactants (4) raising the concentration of the reactants
Answer->
Q 8 Which information about a chemical reaction is provided by a potential energy diagram?
(1) the oxidation states of the reactants and products
(2) the average kinetic energy of the reactants and products
(3) the change in solubility of the reacting substances
(4) the energy released or absorbed during the reaction
Q 9. Given the balanced equation:
Answer-->
Q 10. Given the potential energy diagram for a chemical reaction:
Which statement correctly describes the energy changes that occur in the forward reaction?
(1) The activation energy is 10. kJ and the reaction is endothermic.
(2) The activation energy is 10. kJ and the reaction is exothermic.
(3) The activation energy is 50. kJ and the reaction is endothermic.
(4) The activation energy is 50. kJ and the reaction is exothermic.
Answer-->
Q 11. Which expression represents the ΔH for a chemical reaction in terms of the potential energy, PE, of its
products and reactants?
(1) PE of products + PE of reactants (2) PE of products – PE of reactants
(3) PE of products × PE of reactants (4) PE of products ÷ PE of reactants
Answer->