Answer to Question #222199 in Chemistry for caleb villarreal

Question

I have an unknown volume of gas held at a temperature of 115 K in a container with a pressure of 60atm. If by increasing the temperature to 225 K and decreasing the pressure to 30. atm causes the volume of the gas to be 29 liters, how many liters of gas did I start with? (round to correct sig figs)

Answer 1

P₁ = 60 atm

V₁ = unknown

T₁ = 115 K

P₂ = 30 atm

V₂ = 29 L

T₂ = 225 K

Solution:

Combined Gas Law can be used:

P₁V₁/T₁ = P₂V₂/T₂

Cross-multiply to clear the fractions:

P₁V₁T₂ = P₂V₂T₁

Divide to isolate V₁:

V₁ = (P₂V₂T₁) / (P₁T₂)

Plug in the numbers and solve for V₁:

V₁ = (30 atm × 29 L × 115 K) / (60 atm × 225 K) = 7.4 L = 7 L

V₁ = 7 L

Answer: 7 L