This refers to the force exerted per unit area. It’s like how stepping on a Lego hurts more than stepping on a soft toy - same force, but smaller area!
Pascal (Pa): This is the SI unit for measuring pressure. Just as we measure distance in meters or weight in kilograms, we measure pressure in Pascals.
Avogadro’s Law: Another gas law which states that equal volumes of all gases at the same temperature and pressure contain an equal number of molecules. Like having two different types of balloons - one filled with helium and another with air - both will have the same number of molecules if they're at the same temperature and pressure.