Redox Chemistry and Groups 1, 2 and 7Edexcel International A Level Chemistry: Topic test

20 questions, 54 marks

Edexcel International A Level Chemistry

Redox Chemistry and Groups 1, 2 and 7 topic test

Total 54 marks

Name

Class

Date

1
Nitrogen dioxide, NO₂, reacts with water to form nitric acid and nitrogen monoxide: 3NO₂ + H₂O → 2HNO₃ + NO.
(a)
What are the oxidation numbers of nitrogen in NO₂, HNO₃ and NO respectively?
[1 mark]
A+4, +5, +2
B+4, +5, −2
C+2, +5, +4
D+4, +3, +2
(b)
Which statement about this reaction is correct?
[1 mark]
ANitrogen dioxide is oxidised only
BNitrogen dioxide is reduced only
CNitrogen dioxide is both oxidised and reduced
DWater is reduced to hydrogen
(c)
Write an ionic half-equation for the oxidation of NO₂ to NO₃⁻ in acidic solution.
[2 marks]
Total for question 1: 4 marks
2
Rubidium, Rb, is a Group 1 metal found below potassium.
(a)
How does rubidium compare with potassium?
[1 mark]
AIt has a higher first ionisation energy and reacts less vigorously with water
BIt has a lower first ionisation energy and reacts more vigorously with water
CIt has a lower first ionisation energy and reacts less vigorously with water
DIt has a higher first ionisation energy and reacts more vigorously with water
(b)
Which equation represents the reaction of rubidium with water?
[1 mark]
A2Rb + H₂O → Rb₂O + H₂
BRb + 2H₂O → Rb(OH)₂ + H₂
CRb + H₂O → RbOH + H₂
D2Rb + 2H₂O → 2RbOH + H₂
(c)
Explain why the first ionisation energy of rubidium is lower than that of potassium.
[2 marks]
Total for question 2: 4 marks
3
A student heats 2.95 g of strontium carbonate, SrCO₃ (Mr = 147.6), strongly until it has completely decomposed. Take the molar volume of a gas as 24.0 dm³ mol⁻¹ at room temperature and pressure.
(a)
Write the equation for the decomposition and calculate the volume of carbon dioxide formed, in cm³.
[3 marks]
(b)
Predict whether strontium carbonate decomposes at a higher or lower temperature than calcium carbonate and explain your answer. State the test for carbon dioxide and its result.
[4 marks]
Total for question 3: 7 marks
4
Bromine is extracted from sea water that contains bromide ions at a concentration of 65.0 mg dm⁻³. Chlorine is bubbled through the sea water to displace the bromine. Relative atomic mass: Br = 79.9. Take the molar volume of a gas as 24.0 dm³ mol⁻¹.
(a)
Calculate the minimum volume of chlorine needed to displace all the bromine from 1000 dm³ of sea water, in dm³. Use oxidation numbers to explain what happens to the chlorine and bromide ions, and explain why chlorine can displace bromine.
[6 marks]
(b)
The bromine is then removed from the air stream by reaction with sulfur dioxide and water: Br₂ + SO₂ + 2H₂O → 2HBr + H₂SO₄. State the oxidation number changes, identify the oxidising agent, and write the two ionic half-equations (in acidic solution) and the overall ionic equation.
[6 marks]
Total for question 4: 12 marks
5
A technician has three unlabelled white solids: sodium hydrogencarbonate, ammonium chloride and sodium sulfate.
(a)
Which reagent gives a white precipitate with an aqueous solution of only one of the three solids?
[1 mark]
Adilute hydrochloric acid
Baqueous sodium hydroxide, warmed
Cacidified barium chloride solution
Ddilute nitric acid
(b)
Which observation shows that a solid contains ammonium ions?
[1 mark]
AWarming with aqueous sodium hydroxide gives a gas that turns damp red litmus paper blue
BWarming with aqueous sodium hydroxide gives a gas that turns damp blue litmus paper red
CAdding dilute acid gives a gas that turns limewater milky
DAdding acidified barium chloride gives a white precipitate
(c)
Write the ionic equation, with state symbols, for the reaction that occurs when ammonium chloride solution is warmed with aqueous sodium hydroxide.
[2 marks]
Total for question 5: 4 marks
6
A student titrates 25.0 cm³ portions of sodium hydroxide solution with 0.0500 mol dm⁻³ sulfuric acid, using methyl orange as the indicator. The mean titre is 21.60 cm³. The equation is 2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O. Relative atomic masses: H = 1.0, O = 16.0, Na = 23.0.
(a)
What is the concentration of the sodium hydroxide solution, in mol dm⁻³?
[1 mark]
A0.0432
B0.0216
C0.173
D0.0864
(b)
What colour change is seen at the end point?
[1 mark]
Ared to yellow
Byellow to orange
Cpink to colourless
Dcolourless to pink
(c)
Calculate the concentration of the sodium hydroxide solution in g dm⁻³.
[2 marks]
Total for question 6: 4 marks
7
A student mixes ammonia gas with hydrogen chloride gas in a gas jar and a white solid forms. Relative atomic masses: H = 1.0, N = 14.0, Cl = 35.5.
(a)
Write the equation for the reaction and calculate the mass of solid formed when 0.730 g of hydrogen chloride reacts with excess ammonia.
[3 marks]
(b)
The solid is dissolved in water and acidified silver nitrate solution is added. Give the observation and ionic equation, and describe what happens when dilute aqueous ammonia is then added to the precipitate.
[4 marks]
Total for question 7: 7 marks
8
Solid W is a white crystalline compound that dissolves in water. It is one of potassium carbonate, potassium hydrogencarbonate, potassium sulfate and ammonium sulfate. These observations are made. (1) A flame test gives a lilac flame. (2) Dilute hydrochloric acid added to W gives effervescence, and the gas turns limewater milky. (3) Dilute hydrochloric acid followed by aqueous barium chloride added to a solution of W gives no precipitate. (4) Warming W with aqueous sodium hydroxide gives no gas that turns damp red litmus paper blue. (5) Heating W strongly in a dry test tube gives a gas that turns limewater milky, a liquid that condenses on the cooler part of the tube, and a white solid residue.
(a)
Deduce the identity of W, explaining what each observation shows and why the other three compounds are eliminated. Include the equation for the thermal decomposition.
[6 marks]
(b)
W is potassium hydrogencarbonate, KHCO₃ (Mr = 100.1). A student dissolves 2.000 g of the impure solid in water and makes the solution up to 250.0 cm³. She titrates 25.0 cm³ portions with 0.100 mol dm⁻³ hydrochloric acid using methyl orange. The mean titre is 19.60 cm³. KHCO₃ + HCl → KCl + H₂O + CO₂. Calculate the percentage purity of the solid, and the percentage uncertainty in the titre if the burette reading has an uncertainty of ±0.05 cm³ each time it is read.
[6 marks]
Total for question 8: 12 marks

End of questions

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).