Waec Model Questions Vol1 2022 Chemistry Question 4

Practice practical question 4 from the 2022 Waec Model Questions Vol1 Chemistry examination. This question covers Mole Concept .

Waec Model Questions Vol1 2022 Chemistry Practical
Topic: Mole Concept
Question 4 WAEC_MODEL_QUESTIONS_VOL1 • 2022 • CHEMISTRY • practical

A student carries out the reaction between sodium carbonate and hydrochloric acid to evolve carbon dioxide gas. The procedure is as follows: 1. Accurately weigh 2.00 g of solid Na₂CO₃ and transfer it into a 250 mL conical flask. 2. Add excess dilute HCl (0.1 M) to the flask and immediately fit a delivery tube leading to an inverted, water‑filled 500 mL graduated cylinder (the gas collection over water set‑up). 3. Record the volume of gas collected when the reaction is complete. The temperature of the water bath is 25 °C and the atmospheric pressure is 760 mm Hg. The vapour pressure of water at 25 °C is 23.8 mm Hg. 4. The theoretical stoichiometry for the reaction is: Na₂CO₃ + 2 HCl → 2 NaCl + H₂O + CO₂(g). The volume of gas collected is 450 mL. Using the data above, answer the following questions:

Question Parts

( a )
Calculate the number of moles of Na₂CO₃ that were initially weighed.
( b )
Determine the number of moles of CO₂ gas actually collected, correcting for the water vapour pressure.
( c )
Calculate the percent yield of CO₂ obtained in the experiment.
( d )
Identify two possible sources of error in this experiment and suggest how each could be reduced.

Detailed Solution & Marking Scheme

Get the step-by-step solution, key points required by examiners and detailed marking guidance through the Edcrib AI Tutor.

Reveal Answer

About This Question

This is Waec Model Questions Vol1 2022 Chemistry Question 4. It is a practical question from the 2022 Waec Model Questions Vol1 Chemistry examination.

The question covers Mole Concept .

Master the Exam!

You've seen a preview, but there are thousands more questions plus AI tutor to break down complex solutions.

Unlock Full Access Available for Android & Windows
Chat with Support