Can someone please answer this

Question

I have an unknown volume of gas held at a temperature of 175 K in a container with a pressure of 42 atm. If by increasing the temperature to 270 K and decreasing the pressure to 29.2 atm causes the volume of the gas to be 20 liters, how many liters of gas did I start with?

Answer 1

Look at what you are given:

Ininitial temperature = T1 = 175K

Initial pressure = P1 = 42 atm

Final temperature = T2 = 270K

Final pressure = P2 = 29.2 atm

Final volume = V2 = 20 liters

You are asked to find

Initial volume = V1 = ?

Use the combined gas law:

P1V1/T1 = P2V2./T2

Solve for V1

V1 = P2V2T1 / P1T2

V1 = (29.2 atm)(20 L)(175K) / (42 atm)(270K)

V1 = 9.01 L

(be sure to check the math)