Answer to Question #350558 in General Chemistry for YANYAN

Question

What volume will 200 ml of gas at 20 o C and 800 mm Hg occupy at STP?

Answer 1

Given:

P₁ = 800 mmHg

V₁ = 200 mL

T₁ = 20°C + 273.15 = 293.15 K

P₂ = 760 mmHg (STP)

V₂ = unknown (STP)

T₂ = 0°C + 273.15 = 273.15 K (STP)

Formula: P₁V₁/T₁ = P₂V₂/T₂

Solution:

Combined gas law can be used.

Combined gas law can be expressed as:

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 = (800 mmHg × 200 mL × 273.15 K) / (760 mmHg × 293.15 K) = 196.2 mL

V₂ = 196.2 mL

Answer: 196.2 mL