Combined Gas Law Tutorial

Combined Gas Law:

Combined Gas Law is a gas law which combines Charles's law, Boyle's law, and Gay-Lussac's law.

Combined Gas Law Example:

Case 1: A cylinder contain a gas of volume 30 L, at a pressure of 110 kPa and a temperature of 420 K. Find the temperature of the gas which has a volume 40 L at a pressure of 120 kPa. V_i = 30 L, P_i = 110 kPa, T_i = 420 K, V_f = 40 L, P_f = 120 kPa

Step 1:

Substitute the values in the below final temperature equation: Final Temperature(T_f) = P_fV_fT_i / P_iV_i = (120 x 40 x 420) / (110 x 30) = 2016000 / 3300 Final Temperature(T_f) = 610.91 K This example will guide you to calculate the final temperature manually. Case 2: A cylinder contain a gas of volume 10 L, at a pressure of 80 kPa and a temperature of 200 K. Find the temperature of the gas which has a volume 20 L at a temperature of 220 K. V_i = 10 L, P_i = 80 kPa, T_i = 200 K, V_f = 20 L, T_f = 220 kPa

Step 1:

Substitute the values in the below pressure equation: Final Pressure(P_f) = P_iV_iT_f / T_iV_f = (80 x 10 x 220) / (200 x 20) = 176000 / 4000 Final Pressure(V_f) = 44 kPa This example will guide you to calculate the pressure manually.