Question

Rate of reaction for the combustion of propane is equal to:

\[\ce{C3H8_{(g)} + 5O2_{(g)} -> 3CO2_{(g)} + 4H2O_{(g)}}\]

Options

• `-(Δ["C"_3"H"_8])/(Δ"t") = -(Δ["O"_2])/(Δ"t") = +(Δ["CO"_2])/(Δ"t") = +(Δ["H"_2"O"])/(Δ"t")`

• `-2(Δ["C"_3"H"_8])/(Δ"t") = -5(Δ["O"_2])/(Δ"t") = +3(Δ["CO"_2])/(Δ"t") = +4(Δ["H"_2"O"])/(Δ"t")`

• `-(Δ["C"_3"H"_8])/(Δ"t") = -1/5(Δ["O"_2])/(Δ"t") = +1/3(Δ["CO"_2])/(Δ"t") = +1/4(Δ["H"_2"O"])/(Δ"t")`

• `-2(Δ["C"_3"H"_8])/(Δ"t") = -1/5(Δ["O"_2])/(Δ"t") = +3(Δ["CO"_2])/(Δ"t") = +4(Δ["H"_2"O"])/(Δ"t")`

Answer 1

`-(Δ["C"_3"H"_8])/(Δ"t") = -1/5(Δ["O"_2])/(Δ"t") = +1/3(Δ["CO"_2])/(Δ"t") = +1/4(Δ["H"_2"O"])/(Δ"t")`

Explanation:

Rate of reaction = (−) Rate of disappearance of reactants = (+) Rate of the appearance of products.

Where negative sign indicates that the concentration of reactants decreases and a positive sign indicates that the concentration of products increases.