Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
States of Matter
102 practice questions
Topics covered
Practice questions
41–44 of 44 · Normal
Question 41
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 42
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 43
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.
Question 44
6 marks · Normal
Answer and see the solution →A teacher asks the class to consider a scenario: 'Chlorine gas and a solid sugar cube are each placed in the opposite ends of two sealed glass tubes filled with air. Both tubes are left for several hours at room temperature.'
(a)[2 marks]Explain what happens to the chlorine gas in terms of diffusion.
(b)[2 marks]Describe what would happen to the sugar cube over time and give a reason using particle ideas.
(c)[2 marks]State what is meant by a solution, referring to both the sugar experiment and the key terms 'solute' and 'solvent.'