Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
The Alkali Metals
85 practice questions
Topics covered
Practice questions
71–80 of 85
Question 71
1 mark · Normal
Answer and check →Which statement best predicts what would happen if a small piece of francium was exposed to air at room temperature?
- A.It would remain shiny and not react.
- B.It would tarnish almost instantly.
- C.It would slowly change colour over several days.
- D.It would melt and form a green compound.
Question 72
2 marks · Normal
Answer and see the solution →Give the formula and name for the hydroxide formed when francium reacts with water.
Question 73
4 marks · Normal
Answer and see the solution →Answer the following questions about francium and its properties.
(a)[2 marks]Explain why we can predict the properties of francium, even though it is extremely rare.
(b)[2 marks]State one property francium would have as a solid and one as an aqueous compound.
Question 74
2 marks · Hard
Answer and see the solution →State and explain one reason why francium is predicted to be more reactive than potassium.
Question 75
5 marks · Hard
Answer and see the solution →Francium is a Group 1 alkali metal that has never been seen directly. Chemists use trends to predict its properties.
(a)[1 mark]State the expected physical appearance of francium when freshly cut.
(b)[2 marks]Explain why francium would be stored under oil if it could be collected in the laboratory.
(c)[2 marks]Describe and explain what you would expect to happen if francium was dropped into water.
Question 76
2 marks · Hard
Answer and see the solution →Predict whether francium would form coloured or colourless compounds in water, and explain your answer.
Question 77
5 marks · Easy
Answer and see the solution →This question is about alkali metals and their reactions with air and predictions for francium.
(a)[2 marks]A student weighs out 1.50 g of sodium and exposes it to air. The sodium rapidly forms a white compound. Give the formula for this compound and calculate the maximum mass that could be formed.
(b)[2 marks]Francium is even more reactive than potassium. Predict what you would observe if a piece of francium metal was freshly cut and left in the air, and explain your answer.
(c)[1 mark]Use the information about group trends to estimate whether francium would have a higher or lower melting point than potassium. Justify your answer.
Question 78
5 marks · Easy
Answer and see the solution →Answer the following about compounds of Group 1 metals and the properties of francium.
(a)[2 marks]State the typical colour and solubility in water for compounds of sodium and potassium.
(b)[2 marks]Give the formula and expected colour of the hydroxide formed when francium reacts with water.
(c)[1 mark]Suggest what you would observe when a solution of francium hydroxide is added to universal indicator.
Question 79
5 marks · Easy
Answer and see the solution →Rubidium (Rb) and caesium (Cs) are alkali metals placed below potassium in Group 1 of the Periodic Table.
(a)[1 mark]Rubidium reacts with water to produce rubidium hydroxide and hydrogen gas. Write a balanced equation, including state symbols, for this reaction.
(b)[2 marks]In an experiment, a student places a small piece of caesium in a trough containing 100 cm³ of water. The student collects the hydrogen gas given off and measures its volume as 45 cm³ at room temperature and pressure (rtp).
Calculate the number of moles of hydrogen gas produced. (Molar volume of gas at rtp = 24 000 cm³/mol)
(c)[2 marks]Caesium is stored under oil. State what would be observed if a freshly cut piece of caesium was quickly exposed to air, and explain why this observation occurs.
Question 80
4 marks · Easy
Answer and see the solution →(a)State one observation you would make when rubidium reacts with water.
(b)[1 mark]Potassium reacts with water to form potassium hydroxide and hydrogen. Write a balanced symbol equation for this reaction.
(c)[1 mark]Group 1 metal compounds are usually white or colourless solids. State the typical solubility in water of sodium hydroxide.
(d)[1 mark]Name the colour observed in a solution of potassium iodide.
(e)[1 mark]Explain why rubidium reacts more vigorously with water than sodium.