Answer to Question #157093 in General Chemistry for Makhya

Question

1.  What will be the new volume if 125 mL of Helium gas at 100 0C and 0.981 atm is cooled 35 0C and the pressure increased to 2.5 atm?

Answer 1

P₁ = 0.981 atm

V₁ = 125 mL

T₁ = 100^oC = 373 K

P₂ = 2.5 atm

V₂ = unknown

T₂ = 35^oC + 273 = 308 K

Solution:

The Combined Gas Law can be used:

P₁V₁/T₁ = P₂V₂/T₂

Cross-multiply to clear the fractions:

P₁V₁T₂ = P₂V₂T₁

Divide to isolate V₂:

V₂ = (P₁V₁T₂) / (P₂T₁)

Plug in the numbers and solve for V₂:

V₂ = (0.981 atm × 125 mL × 308 K) / (2.5 atm × 373 K) = 40.5 mL

V₂ = 40.5 mL

Answer: 40.5 mL is the new volume.