IB Chemistry HL 2.1.4 Percentage yield Question Bank

Practise IB Chemistry HL 2.1.4 by applying percentage yield 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 2.1.4—Percentage yield question 1 — IB Chemistry HL

Calculate the mass, in g , of styrene produced from 1.0 kg of ethylbenzene if the yield of the reaction is 90 %.

$\begin{aligned} \text { «mol styrene }=\frac{90}{100} \times \frac{1000}{8(12.01)+10(1.01)} \text { » } \text { «mol styrene }=\text { » } 8.48 \text { «mol» } \text { «mass styrene }=8.48 \times(8(12.01)+8(1.01))=882.88 \text { » } \text { «mass styrene }=\text { » } 880 \text { «g» } \end{aligned}$

Award [2] for correct final answer in range 880-890 «g».

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2.1.4—Percentage yield question 1