Final answer:
During the chemical reaction, the total number of gas volumes decreases from three to two, resulting in a decrease in volume by 33%, under constant pressure and temperature conditions. The correct answer is d.) volume decreases by 33%.
Step-by-step explanation:
The question 'Imagine that the reaction 2 CO (g) + O2 (g) --> 2 CO2 (g) occurs in a container that has a piston that moves to maintain a constant pressure when the reaction occurs at constant temperature. Which of the following statements describes how the volume of the container changes due to the reaction?' concerns the principles of gas behavior under constant pressure, particularly in the context of chemical reactions involving gases.
This chemical equation shows that two molecules of carbon monoxide react with one molecule of oxygen to produce two molecules of carbon dioxide. This means that we have a total of three volumes of gas (2 CO + 1 O2) on the reactants side and two volumes of gas (2 CO2) on the products side. Since the reaction occurs at constant pressure and temperature, the volume is directly proportional to the number of moles of gas (Avogadro's law). Therefore, if we start with three volumes and end with two volumes, the volume would decrease.
The volume would decrease by 33%, because if you take away one third (1 volume) from the initial three volumes, you are left with two volumes, which is a 33% decrease. The correct answer to how the volume of the container changes due to the reaction is: d.) volume decreases by 33%.