Formula Gay-Lussac law (isobaric process) Temperature before Temperature after Volume before Volume after
$$\frac{\class{blue}{V_1}}{\class{blue}{T_1}} ~=~ \frac{\class{red}{V_2}}{\class{red}{T_2}}$$ $$\class{blue}{T_1} ~=~ \frac{\class{blue}{V_1}}{\class{red}{V_2}} \, \class{red}{T_2}$$ $$\class{red}{T_2} ~=~ \frac{\class{red}{V_2}}{\class{blue}{V_1}} \, \class{blue}{T_1}$$ $$\class{blue}{V_1} ~=~ \frac{\class{blue}{T_1}}{\class{red}{T_2}} \, \class{red}{V_2}$$ $$\class{red}{V_2} ~=~ \frac{\class{red}{T_2}}{\class{blue}{T_1}} \, \class{blue}{V_1}$$
Temperature before
$$ \class{blue}{T_1} $$ Unit $$ \mathrm{K} $$ Absolute temperature of the ideal gas before the isobaric process.
Note: The temperature in degrees Celsius must be converted to Kelvin unit!
Temperature after
$$ \class{red}{T_2} $$ Unit $$ \mathrm{K} $$ Absolute temperature of the ideal gas after the isobaric process.
Volume before
$$ \class{blue}{V_1} $$ Unit $$ \mathrm{m}^3 $$ Volume of the ideal gas before the isobaric process. Isobaric means that the pressure of the gas has remained constant during the process.
Volume after
$$ \class{red}{V_2} $$ Unit $$ \mathrm{m}^3 $$ Volume of the ideal gas after the isobaric process.