Reason For Learning
Boyle’s law states that the volume of a ?xed mass of gas at constant temperature is inversely proportional to its pressure. A decrease in the volume of a container means that particles travel shorter distances between collisions with each other and the walls of the container. This results in more collisions per second and hence an increase in the total force exerted per unit area. The pressure therefore increases. Boyle’s law is consistent with kinetic molecular theory.
Charles’ law states that the volume of a ?xed mass of gas at constant pressure is directly proportional to its absolute temperature.
Increasing the temperature of a gas increases the average kinetic energy and therefore the speed of the particles. As they move faster, the particles hit the walls of the container more often and with more force. For the pressure to remain constant, (that is, for the number of collisions to remain the same) there must be a greater distance between the particles and the container walls. This can be achieved only by an increase in volume. So a temperature rise must be accompanied by a volume increase.
Learning Intention
After completing this learning bite you will be able to use:
Boyle’s law for pressure–volume calculations
Charles’ law for temperature–volume calculations.
Key Vocabulary Terms