Question

A sample of oxygen gas has a volume of 36.7 L at 145 kPa and 65. ̊C. What volume will the sample have at STP?

Answer 1

Data Given:

                  Initial Volume = V₁ =  36.7 L

                  Initial Pressure = P₁ =  145 kPa

                  Initial Temperature = T₁ =  65 °C + 273 = 338 K

                  Final Volume = V₂ = ?

                  Final Pressure = P₂ = 101.325 kPa           (Standard Pressure)

                  Final Temperature = T₂ = 273 K                (Standard Temperature)

Formula used:
                      As number of moles are constant, so Ideal Gas equation in following form is used,
                                        P₁ V₁ / T₁  =  P₂ V₂ / T₂
Solving for V₂,
                                    V₂  = P₁ V₁ T₂ / T₁ P₂
Putting Values,

                  V₂ = (145 kPa × 36.7 L × 338 K) ÷ (273 K × 101.325 kPa)

                  V₂ = 1798667 ÷ 27661.25

                  V₂ = 65.02 L