Making insoluble salts
2 marks · NormalDescribe how you would make an insoluble salt of calcium sulfate, starting from solutions of calcium nitrate and sodium sulfate.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
Mix aqueous solutions of calcium nitrate and sodium sulfate. A white precipitate of calcium sulfate will form.
Also accept: Mix the two solutions together and filter out the calcium sulfate precipitate
Common mistakes: Failing to mention that the reactants are solutions; Not stating that calcium sulfate is the precipitate
Show mark scheme and worked solution
Marking points
B1 · 1 mark · States that the two solutions (calcium nitrate and sodium sulfate) are mixed together to produce a reaction.
B2 · 1 mark · States that calcium sulfate is formed as an insoluble salt/precipitate.
Worked solution
Mix solutions of calcium nitrate and sodium sulfate together. Calcium sulfate forms as a white precipitate (an insoluble salt).