Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Solubility curves
19 practice questions
Practice questions
11–19 of 19
Question 11
3 marks · Normal
Answer and see the solution →The solubility curve below shows that at 60°C, the solubility of sodium sulfate is 50 g per 100 g of water. At 30°C, its solubility is 30 g per 100 g of water.
Calculate the maximum mass of sodium sulfate that will dissolve in 250 g of water at 60°C. Show your working.
Question 12
3 marks · Normal
Answer and see the solution →A solution contains 90 g of ammonium nitrate dissolved in 100 g of water at 60°C. The solubility curve for ammonium nitrate shows that at 60°C, the solubility is 90 g per 100 g water, and at 30°C the solubility is 55 g per 100 g water.
Explain what happens as the solution is cooled from 60°C to 30°C. Calculate the mass of ammonium nitrate that will crystallise out. Show your reasoning.
Question 13
4 marks · Normal
Answer and see the solution →The following masses were recorded during a solubility experiment:
Measurement Mass (g) Mass of evaporating dish 18.50 Mass of dish + solution 53.40 Mass of dish + dry solid after evaporation 29.10 (a)[1 mark]Calculate the mass of solid obtained from the solution.
(b)[1 mark]Calculate the mass of water that was present in the solution.
(c)[2 marks]Calculate the solubility of the solid (in g per 100 g water) using your results.
Question 14
1 mark · Normal
Answer and check →Which feature must be present when plotting a solubility curve from data in a table?
- A.A line or curve smoothly joining the points
- B.Bars for each temperature
- C.An unlabelled vertical axis
- D.Dots connected only with straight lines
Question 15
2 marks · Normal
Answer and see the solution →The solubility of sodium carbonate in water at 10°C is 12 g per 100 g of water, and at 30°C is 18 g per 100 g of water. What would be the solubility at 30°C in 50 g of water? Give your answer in grams. Show your calculation.
Question 16
4 marks · Normal
Answer and see the solution →A solution contains 60.0 g of magnesium sulfate completely dissolved in 150 g of water at 70°C. The solubility curve for magnesium sulfate: at 70°C, solubility = 44 g/100 g water; at 30°C, solubility = 30 g/100 g water.
(a)[2 marks]Is the solution at 70°C saturated or unsaturated? Explain your answer.
(b)[1 mark]If the solution is cooled to 30°C and no water evaporates, calculate the maximum mass of magnesium sulfate that remains dissolved.
(c)[1 mark]Calculate the mass of magnesium sulfate that will crystallise out as the solution cools from 70°C to 30°C.
Question 17
2 marks · Hard
Answer and see the solution →A student obtains the following measurements while investigating the solubility of a solid in water: Mass of empty dish = 22.35 g Mass of dish + solution = 58.20 g Mass of dish + dry crystals = 39.10 g Calculate the solubility of the solid in 100 g of water at this temperature. Show your working.
Question 18
5 marks · Hard
Answer and see the solution →The table below shows the solubility of sodium sulfate at different temperatures.
Solubility of sodium sulfate at different temperatures Temperature /°C Solubility / g per 100 g of water 10 12.5 30 19.6 50 29.4 70 40.8 90 53.1 (a)[2 marks]On graph paper, plot a solubility curve for sodium sulfate using the data in the table. Label the axes appropriately.
(b)[1 mark]Estimate the solubility of sodium sulfate at 60°C using your curve.
(c)[2 marks]Describe the trend shown by the solubility curve as temperature increases.
Question 19
2 marks · Hard
Answer and see the solution →The solubility curve for potassium nitrate shows the following data: At 25°C, solubility = 38 g per 100 g of water At 60°C, solubility = 109 g per 100 g of water A solution is prepared by dissolving 70 g of potassium nitrate in 100 g of water at 60°C. Use the solubility curve to determine the temperature at which crystals of potassium nitrate will begin to form when this solution is cooled.