Gas laws u13 h. chem

kinetic energy

a type of energy anything has if it is moving.

• solid has none

• liquid has some

• gas has a lot

kinetic theory of gases

rules or expectations of how we expect gases to behave. if a gas follows all of these rules, then it is considered an ideal gas (also considered a rare gas).

• almost always we find gases w/ exceptions to rules

1. gases consist of molecules that are very small and are far apart relative to their size. they are in constant random motion, constantly collide with one another and walls of container.

2. there are no forces of attraction or repulsion between gas molecules

3. the avg. kinetic energy of gas molecules depends on temp. of gas

   • more temp. = more kinetic energy

elastic solutions

• collisions between gas molecules and the container’s walls is considered this

• gas molecules bounce straight off

• lots of kinetic energy

inelastic solution

• gas molecules when colliding come together

• kinetic energy in this is wasted

mmHg

height of mercury in a mercury barometer

1 atm

• 760 torr

• 760 mmHg

• 101.3 kPa

1 torr

0.133322 kPa

Avogadro’s law

• states that volume of a container is directly proportional to the number of moles of gas in the container

• flexible containers use volume

• rigid containers use pressure

• more gas = more volume of container

Boyle’s law

• states that the pressure of a container is inversely proportional to volume of container

• but pressure is directly proportional to num of moles

Charles’ Law

• states that the volume of a container is directly proportional to the Kelvin gas in a flexible container (e.g. balloons)

  • if external pressure stays constant, and temperature increases, the volume of the container will expand because of more kinetic energy so that the internal pressure can be in equilibrium with the external pressure.

Gay-Lussac’s law

• similar to Charles’s law, but instead explains rigid containers.

• if walls of container do noto expand, when heated, pressure builds and container may explode!

combined gas law

• formula you use when there is a situation in which the pressure, volume, and temperature all change.

  • this happens when there is a container with flexible walls, and where the external pressures may change (e.g. balloon going up into the atmosphere).

• TEMPERATURE FOR THIS FORMULA MUST BE IN KELVINS (K)!!!

converting Celsius into Kelvins