IB Chemistry HL 2.2.12 Arrhenius equation Question Bank

Practise IB Chemistry HL 2.2.12 by applying arrhenius equation to exam-style questions.

Exam points

identify the relevant chemical structure, process or evidence
apply the correct chemical model or equation
evaluate the result using chemical reasoning and data

[Maximum number: 2]

Phenylethene (styrene) is produced from ethylbenzene in a gas-phase equilibrium.

Figure for Question 2.2.12 (HL)—Arrhenius equation question 1 — IB Chemistry HL

The forward reaction is first order with respect to ethylbenzene.

\mathrm{C}_{8} \mathrm{H}_{10}(\mathrm{~g}) \rightleftharpoons \mathrm{C}_{8} \mathrm{H}_{8}(\mathrm{~g})+\mathrm{H}_{2}(\mathrm{~g})

Determine the activation energy of the reaction, $E_{\mathrm{a}}$ , in $\mathrm{kJ} \mathrm{mol}^{-1}$ , from the Arrhenius plot. Use sections 1 and 2 of the data booklet.

gradient =-8900
$\text { « } E_{\mathrm{a}}=-(-8900 \times 8.31)=+74000 \mathrm{~J} \mathrm{~mol}^{-1}=» 74 \mathrm{~kJ} \mathrm{~mol}^{-1}$

Award [2] for correct final answer.

Accept $E_{a}$ in the range 66 to 76 «kJ $\mathrm{mol}^{-1}{ }^{-}{ }^{-}$

Do not accept $E_{a}$ in $\mathrm{J} \mathrm{mol}^{-1}$ .

Award [1 max] for -74 « $\mathrm{kJ} \mathrm{mol}^{-1}$ ».

Accept gradient in the range: -8000 to -9100 for M1.

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2.2.12 (HL)—Arrhenius equation question 1