Answer: 25.07 atm
Explanation:
Given that,
Initial Pressure of gas (P1) = ?
Initial Volume of gas (V1) = 28L
Initial Temperature of gas (T1) = 318K
Final pressure of helium = 20 atm
Final volume of gas (V2) = 34L
Final temperature of gas (T2) = 308K
Since pressure, volume and temperature are given, apply the combined gas equation
(P1V1)/T1 = (P2V2)/T2
(P1 x 28L)/318K = (20 atm x 34L)/308K
28L•P1/318K = 680 atm•L/308K
To get P1, cross multiply
28L•P1 x 308K = 680 atm•L x 318K
8624L•K•P1 = 216240 atm•L•K
Divide both sides by 8624L•K
8624L•K•P1/8624L•K = 216240 atm•L•K/8624L•K
P1 = 25.07 atm
Thus, the original pressure of the gas is 25.07 atmosphere
