<Tr> <Td> P V = k (\ displaystyle PV = k) </Td> <Td> Pressure multiplied by volume equals some constant k (\ displaystyle k). </Td> </Tr> <P> where P is the pressure of the gas, V is the volume of the gas, and k is a constant . </P> <P> The equation states that the product of pressure and volume is a constant for a given mass of confined gas and this holds as long as the temperature is constant . For comparing the same substance under two different sets of conditions, the law can be usefully expressed as </P> <Dl> <Dd> P 1 V 1 = P 2 V 2 . (\ displaystyle P_ (1) V_ (1) = P_ (2) V_ (2).) </Dd> </Dl>

What is the relationship between volume and pressure at constant temperature of a gas