A mixture containing 2.53 g each of CH4(g), C2H4(g) and C4H10(g) is contained in a 1.50 L flask at a temperature of 25°C. How would you calculate the partial pressure of each of the gases in the mixture?
You would calculate the individual pressures of the 3 gases. The total pressure is the sum of the individual pressures.
The above is a restatement of Dalton's law of partial pressures: " in a gaseous mixture, the pressure exerted by each component is the same as the pressure it would exert if it alone occupied the container ". Avogadro's law also states that the pressure is proportional to the amount (the number or number of moles) of gaseous particles.
So all you have to do is calculate the number of moles of each gas, and plug this value into the ideal gas equation. You have the temperature, the volume, and can calculate the number of moles of each gas.