Question :
11) Reaction A releases 24 kJ/mole and has an activation : 1282445
11) Reaction A releases 24 kJ/mole and has an activation energy of 98 kJ/mole. Which statement is correct concerning Reaction A?
A) The overall reaction is endothermic with a high activation energy.
B) The overall reaction is endothermic with a low activation energy.
C) The overall reaction is exothermic with a high activation energy.
D) The overall reaction is exothermic with a low activation energy.
12) Reaction conditions for a hypothetical reaction, X + Y W + Z, are given below. Predict which reaction should occur at a faster rate. (M = molarity)
Reaction
Activation energy
Temperature
1
low
low
2
low
high
3
high
high
4
high
low
A) 1
B) 2
C) 3
D) 4
13) Which response includes all the factors that would increase the rate of a chemical reaction, and no others?
I.Lowering the temperature of the chemical reaction.
II. Significantly increasing the concentration of one of the reactants.
III.Adding a catalyst to an uncatalyzed reaction.
IV.Decrease the reaction surface area.
V.Increasing the pressure on a gaseous reaction system.
A) I and IV
B) II, III and V
C) I, IV and V
D) III only
14) Increasing the temperature of a chemical reaction increases the rate of reaction because ________.
A) the activation energy decreases
B) the activation energy increases
C) the collision frequency of reactant molecules increases
D) both the collision frequency and collision energies of reactant molecules increases
15) Reaction conditions for a hypothetical reaction, A + B C, are given below. Predict which reaction should occur at the slowest rate.
Reaction
Activation energy
Temperature
1
102 kJ/mol
14 °C
2
48 kJ/mol
22 °C
3
102 kJ/mol
22 °C
4
48 kJ/mol
34 °C
A) 1
B) 2
C) 3
D) 4
16) The equilibrium constant for the following hypothetical reaction is two (Keq = 2). The initial concentrations present are [A] = 4, [B] = 8, and [AB] = 16 at 25 °C
AB + Heat A (g) + B (g)
After a stress has been absorbed by the reaction, the new equilibrium concentrations are: [A] = 2, [B] = 1, and [AB] = 64. The stress absorbed by the equilibrium system ________.
A) was a change in the reaction temperature evident by the change in the value of the Keq
B) was a decrease in the concentration of [A]
C) was a decrease in the concentration of [B]
D) was an increase in the concentration of [AB]
17) Which of the following conditions characterizes a system in a state of chemical equilibrium?
A) Concentrations of reactants and products are equal.
B) Rate of forward reaction has dropped to zero.
C) Reactants are being consumed at the same rate they are being produced.
D) Reactant molecules no longer react with each other.
18) Chemical equilibrium is reached in a system when ________.
A) product and reactant concentrations remain constant
B) reactant concentrations steadily decrease
C) product molecules begin reacting with each other
D) complete conversion of reactants to products has occurred
19) A mixture of 1.40 moles of A and 2.30 moles of B was allowed to reach equilibrium. At equilibrium, it is found that 0.90 mole of A is present. How many moles of C are present at equilibrium?
3 A (g) + 2 B (g) 4 C (g)
A) 1.6 moles
B) 0.67 mole
C) 1.1 moles
D) 1.3 moles
20) A chemical equilibrium expression depends on the ________ of a reaction.
A) rate
B) stoichiometry
C) stoichiometry and mechanism
D) mechanism
