Question

For the endothermic reaction CaCO3 (s) CaO (s) CO2 (g) Le Cha^ telier's principle predicts that __________ will result in an increase in the number of moles of CO2. A) decreasing the temperature B) removing some of the CaCO3 (s) C) increasing the pressure D) increasing the temperature E) adding more CaCO3 (s)

Answer 1

Answer:

Increasing the temperature will result in increase in number of moles of CO_{2}

Explanation:

Concentration of pure solids and liquids remain constant throughout a reaction. Hence their concentrations terms are not involved in expression for equilibrium constant. Hence removing or adding solid $CaCO_{3}$ will not affect change in number moles of $CO_{2}$.

In the forward direction, pressure increases due to formation of gaseous CO_{2}. Hence, according to Le-chatelier's principle, increase in pressure will result formation of more reactant.

As it is an endothermic reaction therefore heat is consumed in formation of CO_{2}. So, according to Le-chatelier;s principle, increasing the temperature will result in increase in number of moles of CO_{2}.

Correct option (D)

Answer 2

Answer: The Le-Chatelier's principle predicts that increasing the temperature and adding more $CaCO_3(s)$ will result in an increase in the number of moles of $CO_2$

Explanation:

For an endothermic reaction, heat is getting absorbed during a chemical reaction and is written on the reactant side.

$A+\text{heat}\rightleftharpoons B$

Any change in the equilibrium is studied on the basis of Le-Chatelier's principle. This principle states that if there is any change in the variables of the reaction, the equilibrium will shift in the direction to minimize the effect.

As, heat is getting absorbed during a chemical reaction. This means that temperature is getting increased on the reactant side. If the temperature in the equilibrium is increased, the equilibrium will shift in the direction where, temperature is getting decreased. Thus, the reaction will shift in right direction that is towards the product.

When the concentration of reactant is increased, the equilibrium will shift in the reaction where the concentration of reactant will decrease, which is in the forward direction. So,the reaction is product favored.

For the given chemical reaction:

$CaCO_3(s)\rightleftharpoons CaO(s)+CO_2(g)$

Change in pressure is related to the number of moles of gases.

Here, the products are gases and increasing the pressure will increase the pressure at product side. But, the principle states that the equilibrium will shift in the direction where pressure will decrease. Thus, the reaction will shift to the reactant side.

Hence, the Le-Chatelier's principle predicts that increasing the temperature and adding more $CaCO_3(s)$ will result in an increase in the number of moles of $CO_2$