Gases don’t have a set volume, they can expand or compress to fit any container
If heated up the molecules expand and have more energy so they move faster
Gases feature spread out molecules. A sample of gas has no set volume or set shape. A gas will fill whatever container is available to it.
Definition of pressure from a scientific standpoint: force divided by area.
- like a bed of nails
Newtons third law applies to gasses and pressure because the gas will push on the container with the same force that the container will push with, push of contianer can be reduced by making it bigger
P = F/A
Pressure is defined as force per unit area. When the gas molecules collide with the sides of the container they are in the molecules will apply a force on the sides.
- Expansion: the force is still equal
Barometer is used for pressure
- uses mercury, temperature, a vacuum, and pressure to measure
1 atm = 760mmHg = 760torr = 1.0132bar = 101325 pa (n/m^2)= 14.7 psi (lbs/in^2)
Manometers: tool for measuring the pressure og a gas sample. Connects our gas sample to a column of mercury that is either exposed to atmospheric pressure or a vacuum
- P of gas = height + P of atm
Closed manometer: Pgas = height
Gas Laws
Boyle’s Law: As Volume goes up, Pressure goes down P1V1 = P2V2
Charles’ Law: As temperature increases, volume increases
Avogadro’s Law: Equal volumes of a gas contain the same number of molecules at the same temperature and pressure
Gay-Lussac’s Law: As the temperature of an enclosed gas increases, the pressure increases (constant volume), P and T have a direct linear relationship
Combined Gas Law: P1V1/T1 = P2V2/T2
- valid for the changing in values for any gas sample (moles remain constant)
Ideal Gas Law: PV = nRT where R is a constant
- Temperature is in Kelvin