Question

At STP, a container has 1 mole of Ar, 2 moles chainging the total pressure if one mole of O₂ is of CO₂, 3 moles of O₂ and 4 moles of N₂ Without removed, the partial pressure of O₂

(a) is changed by about 16%

(b) is halved

(c) is changed by 26%

(d) is unchanged

Answer 1

Correct option is (c) is changed by 26%

Remember that partial pressure of a gas mole fraction

Mole fraction of O₂ at start = \(\frac 3{10} \times 100 = 30\)

Mole fraction of O₂ at final stage = \(\left(\frac 3{10} - \frac 29\right) \times 100 = \frac{70}9 \approx 8\)

\(\therefore \) % change = \(\frac 8 {30} \times 100 \approx 26 \) %