chem - kinetic theory of gases

properties of gases

• low density

• spread to fill the available space

• easily compressed

• mix together rapidly

properties of liquids

• high density

• fixed volume; adopt shape of container

• almost incompressible

• mix slowly unless stirred

properties of solids

• high density

• fixed volume; generally rigid shape

• almost incompressible

• do not mix unless finely divided

what are all gases composed of?

• atoms or molecules

kinetic theory of gases

• gases are composed of atoms or molecules

• the total volume of a gas is much greater than the volume of the particles and therefore most of the volume is empty space - LOW DENSITY

• particles move randomly in straight lines and collide with other particles and the walls of the container

• particles move around independently

• the average kinetic energy of the particles increases as the temperature increases

• all collisions are elastic

pressure definition

pressure is the force exerted on a unit area of surface

pressure formula

• N (newtons) / metres squared (m^2) - directly relates to pascals but mostly used in physics

four common units for pressure

• millimetres of mercury (mmHg)

• atmospheres (atm)

• pascals (Pa)

• bars (bar)

converting between units of pressure

units for volume

• litre (L)

• millilitre (mL)

• cubic metre (m^3)

• cubic decimetre (dm^3), 1dm = 10 cm = 100mm

• cubic centimetre (cm^3)

volume equivalents

1mL = 1cm^3

1L = 1dm^3

1L = 1x10^3mL = 1000mL

1m^3 = 1x10^3dm^3 = 1x10^6cm^3

1m^3 = 1x10^3L = 1x10^6mL

the gas laws

there are five laws which explain the behaviour of gases, the first of which is boyle’s law

boyle’s law

for a given amount of gas at constant temperature, the volume of gas is inversely proportional to its pressure

boyle’s law formula