Pressure changesCopy

Learning Objectives

• Describe qualitatively, in terms of molecules, the effect on the pressure of a gas of:
  –– a change of temperature at constant volume
  –– a change of volume at constant temperature
• Recall and use the equation pV = constant for a fixed mass of gas at constant temperature

Contents to learn

Pressure law

It states that “the pressure of a fixed mass of gas is directly proportional to its temperature if the volume is kept constant”

P α T

P = constant (T)

P = KT

P / T = K = constant

Where K is constant.

For two different cases,

P1 / T1 = P2 / T2

Charle’s law

According to this law “the volume of a fixed mass of gas is directly proportional to its temperature, if the pressure is kept constant”

V α T

V = constant X T

V = KT

V / T = constant

Where K is constant.

For two different case,

V1 / T1 = V2 / T2

Boyle’s law

It states that “the pressure of a fixed mass of gas is inversely proportional to its volume if the temperature is kept constant”

P α ( 1 / V )

P = constant (1 / V )

P = K / V

PV = K = constant

Where K is constant.

For two different cases,

P1V1 = P2V2