Baking soda (sodium bicarbonate) decomposes when it is heated: 2 NaHCO31s2 ∆ Na2CO31s2 + CO21g2 + H2O1g2 ΔH° = + 136 kJ Consider an equilibrium mixture of reactants and products in a closed container. How does the number of moles of CO2 change when the mixture is disturbed by the following: (b) Adding water vapor

Le Chatelier's Principle states that if a dynamic equilibrium is disturbed by changing the conditions, the system will adjust itself to counteract that change and restore a new equilibrium. This principle is crucial for predicting how the addition of substances, such as water vapor, will affect the concentrations of reactants and products in a chemical reaction.

The equilibrium constant (K) is a numerical value that expresses the ratio of the concentrations of products to reactants at equilibrium for a given reaction at a specific temperature. Changes in concentration, pressure, or temperature can shift the position of equilibrium, affecting the amounts of CO2 and other species present in the system.

In the context of gas equilibria, adding water vapor increases the total pressure of the system. According to Dalton's Law of Partial Pressures, this can shift the equilibrium position depending on the number of moles of gaseous products and reactants. In this case, the addition of water vapor may favor the production of CO2 if it leads to a decrease in the overall pressure of the gaseous components.