Waec Model Questions Vol1 2022 Chemistry Question 5

Practice essay / theory question 5 from the 2022 Waec Model Questions Vol1 Chemistry examination. This question covers Stoichiometry, Limiting reagent, Theoretical yield, Percent yield, Gas collection .

Waec Model Questions Vol1 2022 Chemistry Essay / Theory
Topics: Stoichiometry Limiting reagent Theoretical yield Percent yield Gas collection
Question 5 WAEC_MODEL_QUESTIONS_VOL1 • 2022 • CHEMISTRY • essay

A student carries out the following reaction in a laboratory: CaCO₃ (s) + 2 HCl (aq) → CaCl₂ (aq) + H₂O (l) + CO₂ (g) The student weighs 2.00 g of calcium carbonate and adds excess hydrochloric acid. The molar masses are: CaCO₃ = 100.09 g·mol⁻¹, CO₂ = 44.01 g·mol⁻¹. The volume of carbon dioxide collected over water at 25 °C and 1.00 atm is 0.35 L. The vapour pressure of water at 25 °C is 23.8 mmHg. Answer the following:

Question Parts

( a )
Identify the limiting reagent and justify your choice.
( b )
Calculate the theoretical volume of CO₂ (at STP, 22.4 L·mol⁻¹) that could be produced from the given amount of calcium carbonate.
( c )
Determine the percent yield of CO₂ based on the volume actually collected (corrected to dry gas at STP).
( d )
Discuss at least two possible reasons why the experimental percent yield may be lower than 100 %.

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About This Question

This is Waec Model Questions Vol1 2022 Chemistry Question 5. It is one of the essay questions from the 2022 Waec Model Questions Vol1 Chemistry examination.

The question covers Stoichiometry, Limiting reagent, Theoretical yield, Percent yield, Gas collection .

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