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WorksheetsY12 Unit 1 Amount of Substance Chemistry
Total questions: 28
Worksheet time: 16mins
For drivers in the UK, the legal limit of the concentration of ethanol (molar mass 46 g mol⁻¹) in the blood is 80 mg per 100 cm³. This is equivalent to a concentration of
17.4 mol dm⁻³
1.74 mol dm⁻³
0.0174 mol dm⁻³
0.00174 mol dm⁻³
Oxygen can be prepared using several different reactions. Which of those given below has the highest atom economy by mass?
NaNO₃ → NaNO₂ + ½O₂
H₂O₂ → H₂O + ½O₂
Cl₂ + H₂O → 2HCl + ½O₂
PbO₂ → PbO + ½O₂
The human body contains around 0.025 g of iodine molecules, I₂. Which of the following shows the number of iodine atoms in 0.025 g of I₂? The Avogadro constant is 6.02 × 10²³ mol⁻¹.
0.025 × 6.02 × 10²³ / 126.9
0.025 × 6.02 × 10²³ / 253.8
253.8 × 6.02 × 10²³ / 0.025
126.9 × 6.02 × 10²³ / 0.025
The compound butane has
the empirical formula C4H10 and the molecular formula C2H5.
the empirical formula C2H5 and the molecular formula C4H10.
the empirical formula C2H5 and the molecular formula CnH2n+2.
the empirical formula CnH2n+2 and the molecular formula C4H10.
Q7. 1.12 g of iron reacts with oxygen to form 1.60 g of an oxide of iron. Use relative atomic masses: What is the empirical formula of the oxide formed?
FeO
Fe2O3
Fe3O4
FeO2
Oxygen gas, O2, can be converted into ozone, O3, by passing it through an electric discharge. 3O2(g) → 2O3(g) In an experiment, a volume of 300 cm3 of oxygen was used but only 10% of the oxygen was converted into ozone. All volumes were measured at the same temperature and pressure. The total volume of gas present at the end of the experiment, in cm3, was
200
210
290
300
Magnesium oxide reacts with dilute hydrochloric acid according to the following equation. MgO(s) + 2HCl(aq) → MgCl2(aq) + H2O(l) How many moles of magnesium oxide, MgO, are required to neutralize 20 cm^3 of 0.50 mol dm^-3 hydrochloric acid, HCl?
0.0010
0.0050
0.010
0.020
Which of these solutions does not contain the same total number of ions as the others?
10.00 cm³ of 0.100 mol dm⁻³ NaCl(aq)
20.00 cm³ of 0.050 mol dm⁻³ NaCl(aq)
20.00 cm³ of 0.050 mol dm⁻³ MgCl₂(aq)
13.33 cm³ of 0.050 mol dm⁻³ MgCl₂(aq)
Sodium nitrate decomposes on heating. 2NaNO₃(s) → 2NaNO₂(s) + O₂(g) What is the maximum volume of oxygen, measured in dm³ at room temperature and pressure, which could be obtained by heating 0.50 mol of sodium nitrate? [Molar volume of a gas = 24 dm³ mol⁻¹ at room temperature and pressure]
3
6
12
24
Hydrogen and oxygen react according to the following equation. 2H₂(g) + O₂(g) → 2H₂O(g) If all volumes are measured at 110 °C and one atmosphere pressure, the volume of steam produced after 50 cm³ of hydrogen react completely with 25 cm³ of oxygen is
25 cm³
50 cm³
75 cm³
100 cm³
The concentration of carbon monoxide in the exhaust gases of a car without a catalytic converter is 0.7 % by volume. In units of parts per million, this concentration is
7
70
700
7000
The recommended limit for safe exposure to sulfur dioxide in the air is 0.000025%. What is this concentration in parts per million, ppm?
25
0.25
0.025
0.0025
Complete combustion of 50 cm³ of a hydrocarbon vapour gave 350 cm³ of carbon dioxide, both gas volumes being measured at the same temperature and pressure. The formula of the hydrocarbon could be
C₈H₁₈
C₇H₁₆
C₆H₁₄
C₅H₁₂
How many moles of atoms are present in 240 cm³ of carbon dioxide at room temperature and pressure?
0.03 moles of atoms
0.01 moles of atoms
0.06 moles of atoms
0.12 moles of atoms
What is the percentage by mass of nitrogen in ammonium nitrate, NH4NO3?
A 14.0%
B 17.5%
C 28.0%
D 35.0%
When gold(III) oxide is heated, it decomposes to form gold and oxygen. Calculate the mass of gold formed when 2.21g of gold(III) oxide is heated to constant mass. [Molar masses: O = 16.0 g mol⁻¹ Au = 197 g mol⁻¹]
1.97 g
2.04 g
2.10 g
2.15 g
Which of the following gas samples occupies the greatest volume at the same temperature and pressure?
1 gram of ethane
1 gram of oxygen
1 gram of fluorine
1 gram of neon
Phosphorus(V) chloride, PCl5, reacts with water according to the equation: PCl5(s) + 4H2O(l) → H3PO4(aq) + 5HCl(aq) If 1.04 g of phosphorus pentachloride (molar mass = 208 g mol⁻¹) is reacted completely with water and the solution made up to 1 dm³, the concentration of the hydrochloric acid in mol dm⁻³ is
0.001
0.005
0.025
0.250
A sample of gas was prepared for use in helium-neon lasers. It contained 4 g of helium and 4 g of neon. What is the ratio of helium atoms to neon atoms in the sample?
A 1 : 1
B 2.5 : 1
C 1 : 5
D 5 : 1
The equation for the dehydration of cyclohexanol, C6H11OH, to cyclohexene, C6H10 is: C6H11OH → C6H10 + H2O 50.0 g of cyclohexanol produced 32.8 g of cyclohexene. [Molar masses / g mol⁻¹: cyclohexanol = 100; cyclohexene = 82] Calculate the percentage yield of cyclohexene.
32.8 %
40.0 %
65.6 %
80.0 %
Q29. (a) Sulfamic acid contains 14.42% by mass of nitrogen, 3.09% hydrogen and 33.06% sulfur. The remainder is oxygen. (i) What is the empirical formula of sulfamic acid?
NH2SO3
NH2SO4
NHSO3
NH3SO3
Write an ionic equation for the reaction of hydrogen ions with carbonate ions. State symbols are not required.
2H⁺ + CO₃²⁻ → CO₂ + H₂O
H⁺ + CO₃²⁻ → HCO₃⁻
2H⁺ + CO₃²⁻ → H₂CO₃
H⁺ + CO₃²⁻ → CO₂ + H₂O
Write a chemical equation to show how the presence of carbon dioxide in water results in the formation of carbonic acid.
CO₂ + H₂O → H₂CO₃
CO₂ + H₂O → CO + H₂CO₃
CO₂ + H₂O → CO₂ + H₂O₂
CO₂ + H₂O → C + H₂O
Write the ionic equation to show how acids react with carbonates.
2H⁺ + CO₃²⁻ → CO₂ + H₂O
2H⁺ + CO₃²⁻ → CO₃ + 2H₂O
2H⁺ + CO₃²⁻ → H₂CO₃
2H⁺ + CO₃²⁻ → CO₂ + 2H₂O
Complete the equation below for the reaction between calcium carbonate and hydrochloric acid by inserting the missing state symbols.
CaCO₃(s) + 2HCl(aq) → CaCl₂(aq) + H₂O(l) + CO₂(g)
CaCO₃(aq) + 2HCl(s) → CaCl₂(l) + H₂O(aq) + CO₂(s)
CaCO₃(l) + 2HCl(g) → CaCl₂(s) + H₂O(g) + CO₂(aq)
CaCO₃(g) + 2HCl(l) → CaCl₂(g) + H₂O(s) + CO₂(l)
Calculate the mass of 1 mol of calcium carbonate. [Assume relative atomic masses: Ca = 40, C = 12, O = 16.]
68 g
100 g
80 g
56 g
Write the equation, including state symbols, for the reaction of sodium with oxygen to produce X.
4Na(s) + O2(g) → 2Na2O(s)
2Na(s) + O2(g) → 2NaO(s)
Na(s) + O2(g) → NaO2(s)
4Na(s) + O2(g) → 2Na2O(s)
Calculate the number of oxygen molecules that react with 1.73 g of sodium. (The Avogadro constant = 6.02 × 10²³ mol⁻¹.)
1.13 × 10²² molecules
6.02 × 10²³ molecules
3.45 × 10²¹ molecules
2.50 × 10²⁰ molecules
