Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
States of Matter
102 practice questions
Topics covered
Practice questions
91–100 of 102
Question 91
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 92
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 93
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 94
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.
Question 95
5 marks · Easy
Answer and see the solution →A scientist describes placing solid iodine in an open dish in a laboratory. After a few hours, no solid remains, and a purple vapour fills the dish.
(a)[1 mark]Describe the arrangement and movement of particles in solid iodine at room temperature.
(b)[1 mark]Identify the name of the process that causes solid iodine to disappear and form a vapour.
(c)[2 marks]Explain, using particle theory, what happens to the particles of iodine during this process.
(d)[1 mark]State one difference between the arrangement of particles in the iodine vapour and in the solid.
Question 96
5 marks · Easy
Answer and see the solution →The diagram below shows particles of a substance in three different boxes, labelled 1 (A), 2 (B), and 3 (C).
Diagrams of particle arrangements in three states. Each diagram represents a different state of matter at room temperature.
(a)[1 mark]Match each box (1, 2, or 3) to the correct state: solid, liquid, or gas.
(b)[1 mark]Describe the arrangement of the particles in box 2.
(c)[1 mark]State what process will occur if the substance in box 1 is heated strongly, and name the state formed.
(d)[2 marks]Describe, using particle theory, what happens to the movement of the particles during this process.
Question 97
5 marks · Easy
Answer and see the solution →A student leaves a dish of water on a sunny windowsill. After a day, most of the water is gone.
(a)[1 mark]State the process that has occurred to the water.
(b)[1 mark]Describe the arrangement of water particles in the liquid state.
(c)[2 marks]Explain, using particle theory, how the process in (a) happens.
(d)[1 mark]Name the new arrangement and movement of the water particles after the process has finished.
Question 98
6 marks · Normal
Answer and see the solution →A student investigates how quickly a purple solid, potassium manganate(VII), spreads through water and compares this to how a coloured gas spreads through air.
(a)[2 marks]Describe, using the particle model, what happens to potassium manganate(VII) when it is placed in water.
(b)[1 mark]State what is meant by the term 'solute' in this experiment.
(c)[2 marks]Explain why the potassium manganate(VII) spreads more slowly in water than a coloured gas spreads in air.
(d)[1 mark]State what is meant by a 'saturated solution.'
Question 99
6 marks · Normal
Answer and see the solution →Two students investigate the diffusion and solubility of a substance.
(a)[2 marks]Student 1 observes that when a cotton wool ball soaked in concentrated ammonia solution is placed at one end of a closed tube, and a cotton wool ball soaked in concentrated hydrochloric acid is placed at the other end, a white ring of ammonium chloride forms closer to the hydrochloric acid end.
Explain why the white ring does not form in the centre of the tube.
(b)[2 marks]Student 2 measures how much of a solid, potassium nitrate, can dissolve in 100 g of water at different temperatures.
Describe how the student can use the results to draw a solubility curve.
(c)[1 mark]State how a solubility curve can be used to determine the mass of potassium nitrate that will dissolve at a specific temperature.
(d)[1 mark]Give one reason why diffusion of gases occurs faster than diffusion of solids dissolved in water.
Question 100
6 marks · Normal
Answer and see the solution →A student performs experiments to investigate how much of a solute dissolves in water, and how diffusion works in gases.
(a)[2 marks]The solubility of potassium nitrate in water at 40°C is 64 g per 100 g of water.
Calculate the maximum mass of potassium nitrate that will dissolve in 250 g of water at this temperature.
(b)[3 marks]In a diffusion tube experiment, the white ring of ammonium chloride forms 12 cm from the ammonia end and 8 cm from the hydrochloric acid end.
Calculate the ratio of speed of ammonia particles to hydrogen chloride particles.
(c)[1 mark]State one reason why it is important to measure the water mass carefully in a solubility experiment.