The synthesis of ammonia from nitrogen and hydrogen is reversible and exothermic: _N2 + _H2 <--> ¬_NH3?

2019-03-13 3:17 am

The synthesis of ammonia from nitrogen and hydrogen is reversible and exothermic:
_N2 + _H2 <--> ¬_NH3
Which of the following changes will shift the reaction at Eq to the right?
Select one:
A. Decreasing the temperature
B. Increasing the concentration of ammonia
C. Increasing the pressure
D. Adding an enzyme (catalyst)
E. A+D
F. A+C
G. B+C
H. C+D

回答 (1)

胡雪8°

2019-03-13 8:50 am

N₂(g) + 3H₂(g) ⇌ 2NH₃(g) …… ΔH < 0

A. True
The forward reaction is exothermic while the backward reaction is endothermic. According to Le Chatelier's principle, the decrease in temperature favors the exothermic reaction and thus the equilibrium position will shift to the right.

B. False
According to Le Chatelier's principle, the equilibrium position will shift to the left in order to counteract the increase in the concentration of NH₃.

C. True
There are 4 moles of gaseous molecules on the left of the equation, and 2 moles on the right. According to Le Chatelier's principle, the equilibrium position will shift to the right in order to decrease the number of gaseous molecules.

D. False
Catalyst has no effect on the position of equilibrium.

The answer: F. A + C

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