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For the gas reaction at low pressure

2NOBr ↔ 2NO + Br2 ΔH = +61.1 kJ

which of the following statements are true?

a) Adding more Br2 shifts reaction to the right

b) Removing some NOBr shifts reaction to the left

c) Increasing temperature shifts reaction to the right

d) Changing temperature is the only thing that does not affect Kp

e) The use of a catalyst will not cause any change in the concentrations once equilibrium is reached

No post. No question.

To determine which of the statements are true, we need to analyze the given reaction and the factors that affect it:

2NOBr ↔ 2NO + Br2

Here are the explanations for each of the statements:

a) Adding more Br2 shifts reaction to the right:
According to Le Chatelier's principle, when you increase the concentration of a reactant, the equilibrium shifts in the direction that reduces the concentration. Since adding more Br2 would increase the concentration of a product, Br2, the equilibrium will shift to the left to counterbalance the increase. Therefore, statement (a) is false.

b) Removing some NOBr shifts reaction to the left:
Similar to the previous explanation, removing NOBr would decrease the concentration of a reactant. Consequently, the equilibrium will shift towards the side with more reactants, in this case, to the right. Therefore, statement (b) is false.

c) Increasing temperature shifts reaction to the right:
For an endothermic reaction, increasing the temperature will shift the equilibrium to the right to absorb the additional heat. As ΔH for this reaction is positive (+61.1 kJ), it is endothermic. Thus, statement (c) is true.

d) Changing temperature is the only thing that does not affect Kp:
The equilibrium constant, represented by Kp, is determined solely by the temperature for a given reaction. However, changing the concentrations or pressures of the reactants or products does not affect Kp. Therefore, statement (d) is false.

e) The use of a catalyst will not cause any change in the concentrations once equilibrium is reached:
A catalyst increases the rate of a reaction but does not affect the position of equilibrium. It achieves this by lowering the activation energy for both the forward and reverse reactions. Thus, a catalyst will not cause any change in the concentrations or the equilibrium position once it is reached. Therefore, statement (e) is true.

In summary, the correct answers are:
- Statement (c) is true.
- Statement (e) is true.