Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Compounds of the alkali metals
19 practice questions
Practice questions
11–19 of 19
Question 11
3 marks · Normal
Answer and see the solution →Most group 1 metal compounds are described as colourless or white and are soluble in water.
(a)[2 marks]Explain why compounds of lithium, sodium, and potassium with colourless anions appear colourless or white.
(b)[1 mark]Suggest why potassium permanganate(VII) solution is purple while sodium chloride solution is colourless.
Question 12
4 marks · Normal
Answer and see the solution →Three students set up an experiment to observe how quickly different alkali metals react with air. Each student cut a fresh piece of either lithium, sodium, or potassium, put it onto a clean white tile, and timed how long it took to lose its shiny appearance (tarnish). The results:
Time for shiny appearance to disappear after cutting (room temperature, seconds) Metal Time (s) Lithium 65 Sodium 24 Potassium 8 (a)[1 mark]Complete the following order of reactivity of the metals with air, from least to most reactive:
________ < ________ < ________
(b)[2 marks]Use the data to explain your answer to part (a).
(c)[1 mark]State the white solid formed when sodium reacts with oxygen in air.
Question 13
1 mark · Normal
Answer and check →Which compound is most likely to form a colourless solution in water?
- A.Potassium chloride
- B.Copper(II) sulphate
- C.Iron(III) nitrate
- D.Nickel(II) chloride
Question 14
2 marks · Normal
Answer and see the solution →State the formula and appearance of the solid produced when lithium burns in air.
Question 15
4 marks · Normal
Answer and see the solution →Group 1 compounds tend to dissolve easily in water.
(a)[1 mark]Describe what would be seen when sodium nitrate is dissolved in water.
(b)[2 marks]Explain why the solution formed is colourless.
(c)[1 mark]State an example of a group 1 compound that is not white or colourless, and give the reason for its colour.
Question 16
3 marks · Normal
Answer and see the solution →A student places a piece of sodium metal weighing 2.3 g in air and leaves it to react until it forms a layer of sodium oxide. The equation for the reaction is:
Calculate the mass of sodium oxide formed from 2.3 g of sodium, assuming all of the sodium reacts completely. (Relative atomic masses: Na = 23, O = 16)
Question 17
2 marks · Hard
Answer and see the solution →Describe what you would observe if a freshly cut piece of potassium is left exposed to air. Explain why this observation occurs.
Question 18
5 marks · Hard
Answer and see the solution →The table lists several Group 1 metal compounds:
(a)[3 marks]Compound Colour Solubility in water Lithium nitrate ? ? Sodium sulfate ? ? Potassium carbonate ? ? Complete the table by stating the usual colour and solubility in water of each compound.
(b)[2 marks]Explain why most compounds of lithium, sodium, and potassium dissolve to form colourless solutions.
Question 19
2 marks · Hard
Answer and see the solution →Explain why alkali metals must be stored under oil, using what happens when they are left uncovered in air.