Chemistry 5070 · O Level · Solids, liquids and gases

Solids, liquids and gases — practice question

A student is examining how soluble potassium chlorate(V) and sodium chloride are, using the apparatus shown.
(a)[2]

Complete the table using the thermometer values.

(b)[4]

Mark the points for both potassium chlorate(V) and sodium chloride on the grid. Draw a smooth curve through the potassium chlorate(V) points and a straight line through the sodium chloride points. Extend each line in both directions so that, at the lower end, each one crosses the $y$-axis and, at the upper end, the lines cross.

(c(i))[1]

Using your graphs, what mass of potassium chlorate(V) is dissolved in $10\text{ g}$ of water at $0\degree\text{C}$?

(c(ii))[1]

What mass of sodium chloride is dissolved in $10\text{ g}$ of water at $0\degree\text{C}$?

(d(i))[1]

Using your graphs, determine the temperature at which the two salts have the same solubility.

(d(ii))[1]

Calculate the solubility of both potassium chlorate(V) and sodium chloride at the temperature you gave in (i).

(e)[2]

The student has two boiling tubes: one contains $2.0\text{ g}$ of potassium chlorate(V) in $10\text{ g}$ of water, and the other contains $2.0\text{ g}$ of sodium chloride in $10.0\text{ g}$ of water. Both tubes are at $40\degree\text{C}$. The mixtures are stirred. Use your graphs to describe what is in each tube.

(f)[2]

Using your graphs, compare how raising the temperature affects the solubility of each salt.

Worked solution & mark scheme

This 14-mark question has a full step-by-step worked solution and mark scheme. One marking point: 32, 55, 69 and 80

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