11 mark
Which of these compounds has the same empirical and molecular formulae?
C2H4
C3H8
C4H10
C5H10
Was this exam question helpful?
Formulae & Equations (Edexcel International AS Chemistry): Exam Questions
Exam code: XCH11
53 mins23 questions
21 mark
Which statement defines the relative atomic mass, Ar, of an element?
The weighted mean mass of an atom of the element compared with 1/12 of the mass of an atom of carbon-12
The mass of the most abundant isotope of the element compared with 1/12 of the mass of an atom of carbon-12
The total mass of one mole of atoms of the element compared with 1/12 of the mass of an atom of carbon-12
The mean mass of the isotopes of the element, ignoring their abundances, compared with 1/12 of the mass of an atom of carbon-12
Was this exam question helpful?
31 mark
What is the formula of chromium(III) sulfate?
CrSO4
Cr2SO4
Cr2(SO4)3
Cr3(SO4)2
Was this exam question helpful?
41 mark
Aqueous silver nitrate is added to aqueous calcium chloride. A white precipitate forms.
Which is the ionic equation for this reaction, with spectator ions omitted?
Ag+ (aq) + Cl− (aq) → AgCl (s)
Ag+ (aq) + Cl− (aq) → AgCl (aq)
Ca2+ (aq) + 2NO3− (aq) → Ca(NO3)2 (s)
CaCl2 (aq) + 2Ag+ (aq) → 2AgCl (s) + Ca2+ (aq)
Was this exam question helpful?
51 mark
What is the formula of ammonium sulfide?
NH4S
NH4S2
(NH4)2S
(NH4)2SO4
Was this exam question helpful?
61 mark
The concentration of nitrogen dioxide in a sample of air is 0.5 ppm.
What is the percentage of nitrogen dioxide molecules in this sample of air?
0.5%
0.005%
0.00005%
0.0000005%
Was this exam question helpful?
11 mark
There are 6.02 × 1023 atoms in 0.25 mol of
He
H2O
BH3
CH4
Was this exam question helpful?
2a1 mark
Ammonium iron(II) sulfate, (NH4)2Fe(SO4)2·6H2O, is a double salt that is used as a source of iron(II) ions.
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
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
2c1 mark
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
Was this exam question helpful?
31 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
Was this exam question helpful?
41 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) + S (aq) → BaSO4 (s) + 2H2O (l)
Ba2+ (aq) + S (aq) → BaSO4 (s)
OH− (aq) + H+ (aq) → H2O (l)
Ba2+ (aq) + 2OH− (aq) + 2H+ (aq) + S (aq) → Ba2+ (s) + S (s) + 2H2O (l)
Was this exam question helpful?
51 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
Was this exam question helpful?
61 mark
How many molecules are there in 8.8 g of carbon dioxide, CO2?
[Avogadro constant, L = 6.02 × 1023 mol-1; Mr(CO2) = 44.0]
1.20 × 1023
3.61 × 1023
6.02 × 1023
5.30 × 1024
Was this exam question helpful?
71 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
Was this exam question helpful?
81 mark
A 4.900 g sample of a compound contains 2.063 g of carbon. The compound also contains 6.43% hydrogen by mass, and the rest is oxygen.
The relative molecular mass of the compound is 342
[Ar values: H = 1.0 C = 12.0 O = 16.0]
What is the molecular formula of the compound?
C11H18O12
C12H22O11
C13H26O10
C14H30O9
Was this exam question helpful?
91 mark
A 0.580 g sample of an organic compound contains carbon, hydrogen and oxygen only. Complete combustion of the sample produces 1.320 g of carbon dioxide and 0.540 g of water.
[Ar values: H = 1.0 C = 12.0 O = 16.0]
What is the empirical formula of the compound?
CH2O3
C2H4O
C3H6O
C5H5O2
Was this exam question helpful?
101 mark
Element X has a relative atomic mass of A. It forms an oxide with the formula XO2.
[Ar value: O = 16.0]
L is the Avogadro constant.
Which expression gives the total number of atoms in m g of XO2?
Was this exam question helpful?
11 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
Was this exam question helpful?
21 mark
Which sample contains the greatest number of atoms?
[Ar values: H = 1.0 C = 12.0 N = 14.0 S = 32.1 Cl = 35.5]
426 mg of chlorine, Cl2
0.321 g of sulfur, S
153 mg of ammonia, NH3
96.0 mg of methane, CH4
Was this exam question helpful?
31 mark
Copper reacts with dilute nitric acid.
…Cu + …HNO3 → …Cu(NO3)2 + …NO + …H2O
When the equation is balanced using the smallest whole numbers, what is the number in front of Cu?
1
2
3
4
Was this exam question helpful?
41 mark
Potassium manganate(VII) reacts with ethanedioic acid in the presence of sulfuric acid. The unbalanced equation is shown.
KMnO4 + H2C2O4 + H2SO4 → K2SO4 + MnSO4 + CO2 + H2O
What is the coefficient of H2O when the equation is balanced using the smallest whole numbers?
3
5
8
10
Was this exam question helpful?