If the temperature remains constant, what will happen to pressure when the amount of gas is increased?

When the temperature remains constant, increasing the amount of gas in a container will lead to an increase in pressure. This relationship is described by Avogadro's Law, which states that at constant temperature and pressure, the volume of a gas is directly proportional to the number of moles of gas present.

In a closed system where the volume is fixed, if you introduce more gas, the molecules will collide more frequently with the walls of the container. Each collision exerts a force on the walls, and as more molecules are present, the frequency and intensity of these collisions increase, resulting in higher pressure. This is a fundamental principle of gas behavior under constant temperature—pressure and quantity of gas are directly related when volume is unchanged.

In contrast, if the gas amount were to decrease, the pressure would drop, and if the quantity remained the same, then pressure would stay constant. Fluctuations in pressure would generally indicate other variable factors, such as changes in volume or temperature, rather than a simple increase in gas quantity. Thus, under the conditions described, the only viable outcome for increased gas amounts at constant temperature and volume is an increase in pressure.