Question

Before you add any gas
At start-up (with no gas particles in the chamber), the pressure of the chamber is 0 atm. Use the definition of gas pressure to explain why.

Give your answer in 6th grade sentences

Answer 1

Gas pressure is the result of gas particles pushing against the walls of a container. When there are no gas particles in the chamber, there is nothing to push against the walls. This means there can't be any pressure. So, when you first start with an empty chamber, the pressure is 0 atm because there are no gas particles to create any force on the walls. Without particles, there’s nothing to make the air press against the chamber. That's why the pressure is zero!