IB Chemistry SL Reactivity 2.1.4 Percentage Yield

Practise calculating theoretical yield from the limiting reactant before comparing it with the experimental product. Apply percentage yield = actual/theoretical × 100, retain…

Exam points

calculate theoretical product from the limiting reactant and equation coefficients
divide experimental by theoretical yield in matching units and multiply by 100
rearrange a stated percentage yield to predict the actual mass or volume obtained

[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 SL

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

$\text { «mol styrene }=\frac{90}{100} \times \frac{1000}{8(12.01)+10(1.01)} \text { » }$

«mol styrene => 8.48 «mol»

«mass styrene $=8.48 \times(8(12.01)+8(1.01))=882.88 »$

«mass styrene => 880 «g»

Marking guidance:

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

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2.1.4—Percentage yield question 1