Formulae & Equations (Edexcel International A Level Chemistry)

Exam Questions

31 mins11 questions
11 mark

Which of these compounds has the same empirical and molecular formulae?

  • C2H4

  • C3H8

  • C4H10

  • C5H10

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2
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1 mark

Which of these atoms has the most neutrons?

  • begin mathsize 16px style In presubscript 49 presuperscript 115 end style

  • Sn presubscript 50 presuperscript 124

  • Sb presubscript 51 presuperscript 123

  • begin mathsize 16px style Te presubscript 52 presuperscript 124 end style

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3
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1 mark

What is the relative formula mass of hydrated sodium carbonate, Na2CO3.10H2O?

[Ar values: H = 1.0 C = 12.0 O = 16.0 Na = 23.0]   

  • 106

  • 142

  • 263

  • 286

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1
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1 mark

There are 6.02 × 1023 atoms in 0.25 mol of

  • He

  • H2O

  • BH3

  • CH4

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2a
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1 mark

Ammonium iron(II) sulfate, (NH4)2Fe(SO4)2·6H2O, is a double salt that is used as a source of iron(II) ions.

a)

What is the relative formula mass of the double salt?

[Ar values:  H = 1.0  N = 14.0  O = 16.0  S = 32.1  Fe = 55.8]

  • 277.9

  • 284.0

  • 392.0

  • 447.8

2b1 mark
b)

Ammonium sulfate is used in the preparation of the double salt.

What types of bond are present in ammonium sulfate?

  • ionic only

  • covalent and ionic only

  • dative covalent and ionic only

  • ionic, covalent and dative covalent

2c
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c)
What is the total number of ions present in 0.1 mol of the double salt?

[Avogadro constant (L) = 6.02 × 1023mol−1]

  • 1.80 × 1023

  • 2.41 × 1023

  • 3.01 × 1023

  • 6.62 × 1023

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3
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1 mark

The equation for the complete combustion of hexane is shown.

C6H14 + 9 1⁄2O2 → 6CO2 + 7H2O

How many molecules of carbon dioxide are formed when 2 × 10−3 mol of hexane undergoes complete combustion?
[Avogadro constant L = 6.02 × 1023 mol−1]

  • 1.20 × 1021

  • 7.22 × 1021

  • 8.43 × 1021

  • 3.18 × 1023

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4
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1 mark

Barium hydroxide reacts with sulfuric acid as shown.

Ba(OH)2 (aq) + H2SO4 (aq) → BaSO4 (s) + 2H2O (l)

Which is the ionic equation for this reaction?

  • Ba2+ (aq) + 2OH(aq) + 2H+ (aq) + Sbegin mathsize 16px style O subscript 4 to the power of 2 minus sign end style (aq) → BaSO4 (s) + 2H2O (l)

  • Ba2+ (aq) + Sbegin mathsize 16px style O subscript 4 to the power of 2 minus sign end style (aq) → BaSO4 (s)

  • OH(aq) + H+ (aq) → H2O (l)

  • Ba2+ (aq) + 2OH(aq) + 2H+ (aq) + Sstraight O subscript 4 superscript 2 minus end superscript (aq) → Ba2+ (s) + Sbegin mathsize 16px style O subscript 4 to the power of 2 minus sign end style (s) + 2H2O (l)

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5
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1 mark

An oxide of lead contains 90.7% by mass of lead.

What is the formula of this oxide?

[Ar values: O = 16.0 Pb = 207.2]

  • PbO

  • PbO2

  • Pb2O3

  • Pb3O4

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6
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1 mark

A sample of seawater with a mass of 1 kg contains 6 × 10−9 g of gold.

How many atoms of gold, to one significant figure, are there in 1 g of this seawater?

[Ar value: Au = 197 Avogadro constant = 6 × 1023 mol−1]

  • 2 × 1010

  • 4 × 1012

  • 2 × 1013

  • 4 × 1015

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