Question

Does the number of moles of products increase, decrease, or remain the same when each of the following equilibria is subjected to an increase in pressure by decreasing the volume?

1- CO(g)+H2O(g)⇌CO2(g)+H2(g)
2- 2CO(g)⇌C(s)+CO2(g)
3- N2O4(g)⇌2NO2(g)
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Ethyl acetate, a solvent used in many fingernail-polish removers, is made by the reaction of acetic acid with ethanol:
CH3CO2H(soln)Aceticacid +C2H5OH(soln)Ethanol⇌CH3CO2H(soln)Ethylacetate+H2O(soln)ΔH∘=−2.9kJ
Part A
Does the amount of ethyl acetate in an equilibrium mixture increase or decrease when the temperature is increased?
increase
decrease
Part B
How does Kc change when the temperature is decreased? Justify your answers using Le Chatelier's principle.
How does change when the temperature is decreased? Justify your answers using Le Chatelier's principle.
As the temperature is decreased, the reaction shifts from left to right. The product concentrations increase, and the reactant concentrations decrease. This corresponds to an increase in Kc.
As the temperature is decreased, the reaction shifts from right to left. The product concentrations decrease, and the reactant concentrations increase. This corresponds to an decrease in Kc.
As there is neither products no reactants in gas state the temperature does not shift the reaction. So decrease in temperature does not change Kc.
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A platinum catalyst is used in automobile catalytic converters to hasten the oxidation of carbon monoxide:
2CO(g)+O2(g)⇌Pt2CO2(g)ΔH∘=−566kJ
Suppose that you have a reaction vessel containing an equilibrium mixture of CO(g), O2(g), and CO2(g). Under the following conditions, will the amount of CO increase, decrease, or remain the same after each of the following changes?
A platinum catalyst is added.
increase
decrease
remain the same
The temperature is increased.
increase
decrease
remain the same
The pressure is increased by decreasing the volume.
increase
decrease
remain the same
The pressure is increased by adding argon gas.
increase
decrease
remain the same
The pressure is increased by adding gas.
increase
decrease
remain the same

Answer 1

1-remain the same

2- remain the same

3-decrease

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- decrease

- As the temperature is decreased, the reaction shifts from left to right. The product concentrations increase, and the reactant concentrations decrease. This corresponds to an increase in Kc.

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1- decrease

2-increase

3-decrease

4-remain the same

5-decrease

Step-by-step explanation:

According to Le Chateliers principle, an increase in the volume of a gaseous system at equilibrium will shift the equilibrium position towards the side in which there are less volumes. Hence the answers written. When there is no change in volume, the number of moles of products remain the same.

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For an exothermic reaction, increasing the temperature shifts the equilibrium to the lefthand side.

When temperature is decreased, the equilibrium position will shift towards the right according to Le Chateliers principle

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Addition of a catalyst aids the reaction in which CO is consumed to proceed faster hence CO decreases in the system.

Since the reaction is exothermic, according to Le Chateliers principle, when the temperature is increased, the equilibrium position shifts towards the lefthand side and more CO is now present in the system.

When the pressure of the system is increased, the equilibrium position will shift towards the right hand side and more CO is converted to products hence its concentration in the system decreases.

Addition of argon gas has no effect on the equilibrium position since it does not participate in the reaction. However, addition of the reactant gases increases the rate of reaction and shifts the equilibrium position towards the right hand side thus decreasing the concentration of CO in the system.