PHYSICS - PROPERTIES OF MATTER - Gas laws and kinetic model

gas laws describe

relationships between pressure, volume, and temperature for a fixed mass of gas

Boyle’s law

relationship between pressure and volume at a constant temperature

pressure is inversely proportional to the volume

P1V1 = P2V2

1 = initial

2 = finalfw

Charles’ law

relationship between volume and temperature at constant pressure

volume is directly proportional to the temperature in Kelvins

V1/T1 = V2/T2

Gay-Lussac’s law

relationship between pressure and temperature at constant volume

pressure is directly proportional to the temperature in Kelvin

P1/T1 = P2/T2

general gas law

P1V1/T1 = P2V2/T2

pressure

force acting per unit of area

P = F/A

Pascals Pa

A = area m²

F = force N

what causes gas pressure?

collison of gas particles with the walls of their container

Factors affecting gas pressure

temperature - increased temperature = increase in kinetic energy of particles, faster particles collide with walls more frequently and with greater force, increasing pressure

volume - reducing volume of container forces gas particles to collide more frequently with walls, increasing pressure

number of particles - adding mire gas particles increases number of collisions, increasing pressure

kinetic theory

gas particles move randomly and collide with walls of the container

each collision exerts a force on the wall

total force per unit area equals pressure

kinetic model

explains behaviour of matter in terms if the movement and arrangement of particles

describes states of matter and helps understand gas laws and how temperature, pressure, and volume are related

solids

particles tightly packed in regular pattern

strong intermolecular forces hold particles in fixed positions

particles vibrate around fixed positions

particles have low kinetic energy

fixed shape and volume

cannot flow or be compressed

liquids

particles close together in irregular pattern

weaker intermolecular forces than solids

particles can move past eachother

random motion allows liquida to flow

particles have moderate kinetic energy

fixed volume but no fixed shape

cannot be compressed easily

gases

particles far apart and randomly arranged

weak intermolecular forces between particles

particles move randomly in all directions at high speeds

particles have high kinetic energy

no fixed shape or volume

compresible due to large spaces between particles

relationship between temperature and kinetic energy

average kinetic energy of particles ∞ temperature (K)

absolute zero

0 kelvins

-273⁰C

application in hot air ballons

heating air inside balloon increases speed of particles

causing air to expand and become less dense than cooler air outside allowing balloon to rise

application in explosions

rapid temperature increases causes dramatic rise in pressure, leading ti explosions

assumtions of kinetic model

gas particles move in continuous, random directions

volume of individual gas particles is negligible compared to the total volume of the gas

collisions between particles with walls of container are elastic (no energy lost during collison)

gas particles do not exert attractive or repulsive forces on each other