At constant pressure , the volume of a given mass of gas is directly proportional to the absolute temperature.
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the amount of change in either volume or pressure of a given volume of gas is directly proportional to the change in the absolute temperature.
If the volume of a gas is kept constant and the temperature is increased, the pressure increases in direct proportion to the increase in absolute temperature. A gas will expand or contract in direct proportion to increase or decrease in temperature. If a gas is confined so that it will not expand, its pressure will increase or decrease in direct proportion to temperature.
Charles's law is one of the gas laws.