Waec Model Questions Vol1 2023 Chemistry Question 4

Practice practical question 4 from the 2023 Waec Model Questions Vol1 Chemistry examination. This question covers Mole Concept .

Waec Model Questions Vol1 2023 Chemistry Practical
Topic: Mole Concept
Question 4 WAEC_MODEL_QUESTIONS_VOL1 • 2023 • CHEMISTRY • practical

A student carries out a gravimetric analysis to determine the purity of a sample of calcium carbonate (CaCO₃). The procedure is as follows: 1. A 1.250 g sample of the solid is weighed. 2. The sample is dissolved in excess hydrochloric acid. The carbon dioxide gas evolved is collected over water at 25 °C and 760 mmHg. The volume of gas collected is 0.560 L. The vapour pressure of water at 25 °C is 23.8 mmHg. 3. The calcium ion in solution is precipitated as calcium oxalate monohydrate by adding excess oxalic acid. The precipitate (CaC₂O₄·H₂O) is filtered, washed, dried and weighed, giving a mass of 0.450 g. Using the data above, answer the following questions.

Question Parts

( a )
Calculate the number of moles of CaCO₃ originally present in the sample using the gas‑collection data.

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This is Waec Model Questions Vol1 2023 Chemistry Question 4. It is one of the practical questions from the 2023 Waec Model Questions Vol1 Chemistry examination.

The question covers Mole Concept .

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