Pressure in gases

Pressure in Gases PPT

1. Motion of Molecules and Pressure Moving gas molecules collide with the inner walls of the container and exert a force on it T he force exerted per unit area is thus called gas pressure. Pressure in gases

2. Pressure−Temperature Relationship of a Gas At a higher temperature, the air molecules have greater speeds (greater average kinetic energy ). The air molecules will then bombard the walls of their container more forcefully and more frequently . This causes an increase in gas pressure inside the container. P T

3. Volume−Temperature Relationship of a Gas When the air is heated, the increased temperature causes the air molecules to move at higher speeds The air molecules will then bombard the walls of their container more forcefully and more frequently ; gas pressure increases The air expands and the air molecules move further apart causing the air molecules to occupy a larger volume . T hey collide with the walls less frequently , but more forcefully and maintaining constant pressure V T

4. More frequent collisions, but each collision is less forceful. Less frequent collisions, but each collision is more forceful . Same pressure (atmospheric pressure) Volume−Temperature Relationship of a Gas

5. Pressure−Volume Relationship of a Gas When the volume of the gas is decreased , the number of air molecules per unit volume increases . The air molecules will therefore bombard the walls of the container more frequently . This causes an increase in the force exerted on the walls of the container, and hence an increase in the gas pressure . P V 1