Answer is: 5,9. Effusion is leakage of gas
through a small hole. Gases with a lower molecular mass effuse more speedy than gases with a higher molecular mass. R<span>elative rates of effusion is related to the molecular mass. </span>M(O₂) = 32g/mol. M(CO₂) = 44g/mol. t₁ = 5s. t₂ = ? t₂/t₁ = √(M(CO₂)/M(O₂)). t₂ = 1,17·5s = 5,9s.