Neco Model Questions Vol1 2025 Chemistry Question 8

Practice essay / theory question 8 from the 2025 Neco Model Questions Vol1 Chemistry examination. This question covers solubility, solubility_product, experimental_methods .

Neco Model Questions Vol1 2025 Chemistry Essay / Theory
Topics: solubility solubility_product experimental_methods
Question 8 NECO_MODEL_QUESTIONS_VOL1 • 2025 • CHEMISTRY • essay

A student carried out a solubility experiment to determine the solubility of calcium sulphate (CaSO4) in water at two different temperatures using the saturated‑solution method. The apparatus shown in the diagram was used.

Question Parts

( a )
Write the balanced dissolution equation for calcium sulphate in water.
( b )
Explain why excess solid CaSO4 was added to the water and why the mixture was stirred for 30 minutes before filtration.
( c )
At 25 °C, 0.845 g of CaSO4 was recovered after filtration, washing, drying and weighing. The volume of water used to prepare the saturated solution was 250.0 mL. Calculate the solubility of CaSO4 in grams per 100 mL of water at 25 °C. Show all steps.
( d )
The experiment was repeated at 50 °C and 0.970 g of CaSO4 was recovered from the same 250.0 mL of water. Using the solubilities obtained, calculate the solubility product (Ksp) of CaSO4 at each temperature and comment on the effect of temperature on its solubility, relating your answer to Le Chatelier’s principle.
( e )
Suggest two possible sources of experimental error that could affect the accuracy of the solubility values and propose a method to minimise each error.

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About This Question

This is Neco Model Questions Vol1 2025 Chemistry Question 8. It is one of the essay questions from the 2025 Neco Model Questions Vol1 Chemistry examination.

The question covers solubility, solubility_product, experimental_methods .

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