why do gases exert pressure?

Answer 1

Each time a molecule bounces off the wall of a container, it exerts a tiny force for short period of time. Imagine placing your hand of a wall, and having a basket ball bounce off of it. I mentioned that analogy because my brother broke his finger that way once. Well anyway, you've got zillions of molecules doing this constantly. The effect is a net average force per unit area averaged over a large area for a long period of time. That's the definition of pressure.

Answer 2

Pressure in gases is caused by the movement of the molecules colliding with each other and the walls of the container. As temperature and/or volume changes, the motion and therefore the number of collisions change and the pressure changes accordingly.

Answer 3

In short, gas molecules hit the walls of the container, and as a result they change direction. This means that they are change momentum; conservation lawa say that an equal change of momentum is exerted on the container walls, and this is seen at macroscopic scale as pressure.

Answer 4

If they are heated gases, its because the molecules are vibrating and bouncing off one another, therefore going in oppisite directions which leads to expansion and pressure.

Answer 5

gases are always trying to expand out ward

example

when you blow air into a balloon

gas is putting pressure to expand the balloon