EOY Practice Paper: End-of-Year Examination — question paper (print)

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QQ/S3CH/EOY

Secondary 3 · Chemistry (G2 / G3)

EOY Practice Paper

End-of-Year Examination

Duration: 90 minutes

Total: 60 marks

Name:

Class:

Date:

READ THESE INSTRUCTIONS FIRST

Write your name, class and register number in the spaces at the top of this page.
Answer all questions.
Give numerical answers correct to 3 significant figures unless stated otherwise, with units where a quantity is calculated.
Chemical equations should be balanced, with state symbols shown where the question asks for them.
The number of marks is given in brackets [ ] at the end of each question or part question.
The total number of marks for this paper is shown on its cover.

Original practice material written for the MOE Chemistry syllabus. It is not an official MOE or school examination paper. The full Sec 3 year (Chapters 1–7).

For Examiner’s Use
Section A	/ 20
Section B	/ 40
Total	/ 60

Section A: Multiple-choice questions[20 marks]

Answer all questions. For each question, write the letter (A, B, C or D) of the correct answer.

1
Which is a pure substance?
1. Aclean air
2. Bdistilled water
3. Csea water
4. Dstainless steel
( )
2
The best method for separating ethanol from a mixture of ethanol and water is
1. Afiltration
2. Bevaporation to dryness
3. Cpaper chromatography
4. Dfractional distillation
( )
3
On a chromatogram, the Rf value of a dye is calculated from
1. Adistance moved by dye ÷ distance moved by solvent front
2. Bdistance moved by solvent front ÷ distance moved by dye
3. Cmass of dye ÷ volume of solvent
4. Ddistance moved by dye × distance moved by solvent front
( )
4
In which state of matter are the particles furthest apart and moving fastest, on average?
1. Asolid
2. Bliquid
3. Cgas
4. Dthe particles are the same in every state
( )
5
Which change is sublimation?
1. Aice melting to water
2. Bsolid iodine turning directly into purple vapour
3. Cwater freezing to ice
4. Ddew forming on grass
( )
6
A particle has 17 protons, 18 neutrons and 18 electrons. This particle is
1. Aa chlorine atom
2. Ba chloride ion, Cl⁻
3. Can argon atom
4. Da chloride ion, Cl⁺
( )
7
Isotopes of the same element have identical chemical properties because they have the same
1. Anucleon number
2. Bnumber of neutrons
3. Cdensity
4. Dnumber of electrons
( )
8
The formula of aluminium sulfate is
1. AAlSO₄
2. BAl₂SO₄
3. CAl₂(SO₄)₃
4. DAl₃(SO₄)₂
( )
9
A covalent bond is formed by
1. Athe transfer of electrons between atoms
2. Bthe sharing of a pair of electrons between atoms
3. Cthe attraction between two ions
4. Dthe sharing of protons between nuclei
( )
10
Which solid conducts electricity at room temperature?
1. Aiodine
2. Bsodium chloride
3. Csulfur
4. Dgraphite
( )
11
The relative formula mass of Ca(OH)₂ is
1. A74
2. B58
3. C57
4. D42
( )
12
What is the mass of 0.20 mol of sodium hydroxide, NaOH? (Mr = 40)
1. A200 g
2. B40 g
3. C8.0 g
4. D0.8 g
( )
13
The mass of carbon dioxide in 24 dm³ of the gas at room temperature and pressure is (molar volume = 24 dm³/mol; Mr of CO₂ = 44)
1. A1.8 g
2. B44 g
3. C24 g
4. D11 g
( )
14
The percentage by mass of nitrogen in ammonium nitrate, NH₄NO₃ (Mr = 80), is
1. A17.5%
2. B18%
3. C28%
4. D35%
( )
15
A solution has pH = 13 at room temperature. Which statement is correct?
1. AIt is a strongly alkaline solution with a high OH⁻ concentration.
2. BIt is a strongly acidic solution with a high H⁺ concentration.
3. CIt is neutral.
4. DIt is weakly acidic.
( )
16
The ionic equation for the neutralisation of any strong acid by any strong alkali is
1. AH⁺ + Na⁺ → NaH
2. BOH⁻ + H₂O → H₃O⁺
3. CH⁺ + OH⁻ → H₂O
4. DH⁺ + O²⁻ → OH⁻
( )
17
An oxide reacts with both dilute hydrochloric acid and aqueous sodium hydroxide. The oxide is
1. Abasic
2. Bamphoteric
3. Cneutral
4. Dacidic
( )
18
A gas turns limewater milky. The gas is
1. Ahydrogen
2. Boxygen
3. Cammonia
4. Dcarbon dioxide
( )
19
A solution contains one cation. Adding aqueous sodium hydroxide gives a white precipitate that is insoluble in excess alkali. The cation is
1. ACa²⁺
2. BCu²⁺
3. CFe³⁺
4. DZn²⁺
( )
20
A white precipitate formed with aqueous ammonia dissolves in excess ammonia. The cation is
1. AAl³⁺
2. BZn²⁺
3. CCa²⁺
4. DPb²⁺
( )

Section B: Structured questions[40 marks]

Answer all questions in the spaces provided. Show all necessary working. Give numerical answers to 3 significant figures where appropriate, with units.

1
This question is about purification and analysis.
1. (a)
  Name the technique used to separate two miscible liquids with different boiling points.
  [1]
2. (b)
  Describe how the purity of a liquid sample can be checked using its boiling point.
  [2]
3. (c)
  State why the solvent front in paper chromatography must not be allowed to reach the top edge of the paper.
  [2]
2
Element X has the electronic configuration 2.8.6.
1. (a)
  Describe the arrangement and movement of the particles in solid X and in gaseous X.
  [2]
2. (b)
  State the group and period of element X.
  [2]
3. (c)
  State whether X is a metal or a non-metal, and write the formula of the ion it forms.
  [2]
3
This question is about bonding.
1. (a)
  Describe the bonding in a molecule of water.
  [2]
2. (b)
  A molecule of methane is described as CH₄ with four single covalent bonds. State how many shared pairs of electrons surround the central carbon atom.
  [1]
3. (c)
  Explain why aqueous sodium chloride conducts electricity but liquid hexane, a covalent molecular liquid, does not.
  [4]
4
2.80 g of iron wool reacts completely with chlorine gas. The only product is 8.125 g of an iron chloride. (Ar: Fe = 56; Cl = 35.5)
1. (a)
  Calculate the moles of iron used.
  moles of Fe =mol[1]
2. (b)
  Show that the mass of chlorine that reacted is 5.325 g, and calculate the moles of Cl₂ molecules this represents. (Mr of Cl₂ = 71)
  moles of Cl₂ =mol[3]
3. (c)
  Hence determine the empirical formula of the iron chloride formed.
  [4]
5
25.0 cm³ of aqueous sodium hydroxide of unknown concentration is neutralised by exactly 20.0 cm³ of 0.100 mol/dm³ sulfuric acid: H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O.
1. (a)
  Calculate the moles of sulfuric acid used.
  moles of H₂SO₄ =mol[2]
2. (b)
  Deduce the moles of sodium hydroxide neutralised.
  moles of NaOH =mol[2]
3. (c)
  Calculate the concentration of the sodium hydroxide solution in mol/dm³.
  concentration =mol/dm³[3]
6
Solution W contains a single cation and a single anion. Tests on separate portions of W give these results. Test 1: aqueous sodium hydroxide is added drop by drop — a white precipitate forms, which dissolves in excess to give a colourless solution. Test 2: aqueous ammonia is added drop by drop — a white precipitate forms, which dissolves in excess. Test 3: dilute nitric acid then aqueous barium nitrate are added — a white precipitate forms.
1. (a)
  Identify the cation in W, giving your reasoning from Tests 1 and 2.
  [2]
2. (b)
  Identify the anion in W from Test 3.
  [1]
3. (c)
  Name compound W.
  [1]
4. (d)
  Write the ionic equation, with state symbols, for the reaction in Test 1.
  [2]
5. (e)
  A separate solution of W is tested with sodium carbonate solution instead. State the observation and write the ionic equation for the reaction.
  [1]

— End of paper —