Chemistry 5070 · O Level · Experimental design

Experimental design — practice question

A student is given two bottles, A and B, together with some water. One bottle contains $1.00\,\text{g}$ of solid potassium chloride, $\text{KCl}$. The other bottle contains $1.00\,\text{g}$ of solid calcium chloride, $\text{CaCl}_2$. Dissolving potassium chloride in water is endothermic. Dissolving calcium chloride in water is exothermic. Devise experiments, using the dissolving of the solids in water, to determine which compound is in each bottle and which compound gives the larger heat change per gram of solid.
(main)[6]

Use laboratory apparatus to plan experiments that identify the compounds in bottles A and B and show which compound gives the greatest heat change per gram of solid. Your plan should include every measurement needed and should use the same method for both solids.

Worked solution & mark scheme

This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: Each solid is stirred with water

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