11 mark
What is the number of molecules in 500 cm3 of oxygen under room conditions?
(the Avogadro constant L = 6.023 x 1023)
3.01 x 1023
3.01 x 1026
1.20 x 1021
1.26 x 1022
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1.3 The Mole, Avogadro & The Ideal Gas Equation
21 mark
Ethane has the formula C2H6.
What is the mass in grams of one molecule of ethane? (Ar: C = 12.0; H = 1.0)
(the Avogadro constant L = 6.023 x 1023)
1.81 x 1025
5.00 x 10-23
30.0
3.00 x 10-23
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31 mark
A 20 pence coin contains copper and nickel. One coin has a mass of 5.00 g and contains 84% copper by mass.
How many copper atoms are there in one coin?
(the Avogadro constant L = 6.023 x 1023)
8.43 x 1021
3.98 x 1022
4.29 x 1024
0.071
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41 mark
A 5.62 g sample of anhydrous sodium sulfate, Na2SO4, is dissolved in water and the solution made up to 250 cm3 in a volumetric flask.
What is the concentration in mol dm-3 of the hydrated sodium sulfate solution?
0.61
1.6 x 10-4
0.16
0.016
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51 mark
A student prepared 250 cm3 of a 0.0800 mol dm-3 solution of borax, Na2B4O7 ·10H2O in water in a volumetric flask.
What is the mass of borax crystals needed to make up this solution?
5.240 g
4.384 g
0.080 g
7.624 g
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61 mark
How many moles of oxygen are there in 500 cm3 of gas at 298 K and 105 000 Pa?
(The gas constant R = 8.31 J K-1 mol-1)
0.020 mol
2.02 x 10-5 mol
47.2 mol
2.12 x 104 mol
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71 mark
How many molecules of nitrogen gas are in 4.00 g?
(the Avogadro constant L = 6.023 x 1023)
8.61 x 1022
4.22 x 1024
6.75 x 1025
1.75 x 1023
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81 mark
In an experiment, 0.700 mol of CO2 was produced. This gas occupied a volume of 0.0450 m3 at a pressure of 100 kPa.
What is the temperature of CO2 in ℃?
(The gas constant R = 8.31 J K-1 mol-1)
774
-272
501
273
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91 mark
Iron displaces silver from silver nitrate solution. The ionic equation is:
Fe (s) + 2Ag+ (aq) → Fe2+ (aq) + 2Ag (s)
What is the maximum mass of silver that can be displaced using 9.52 g iron and excess silver nitrate solution?
(Ar: Fe 55.8; Ag 107.9)
3.2 x 10-3 g
18.3 g
317.4 g
36.7 g
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101 mark
What is the mass of 0.56 moles of potassium dichromate (VI), K2Cr2O7?
79.52 g
164.75 g
525.36 g
155.79 g
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11 mark
In a titration, 25.0 cm3 of a sodium sulfite solution required 45.0 cm3 of 0.0200 mol dm-3 potassium manganate (VII) solution to reach the endpoint.
2MnO4- (aq) + 5SO32- (aq) + 6H+ (aq) → 2Mn2+ (aq) + 5SO42- (aq) + 3H2O (l)
What is the concentration of the sodium sulfite solution?
0.014 mol dm-3
0.056 mol dm-3
0.090 mol dm-3
0.900 mol dm-3
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21 mark
Iron and chromium can be made into an alloy called ferrochrome. Ferrochrome can be dissolved in dilute sulfuric acid to produce FeSO4 and Cr2(SO4)3. The FeSO4 reacts with acidified K2Cr2O7 as shown in the equation below:
14H+ + 6Fe2+ + Cr2O72- → 2Cr3+ + 6Fe3+ + 7H2O
1.00 g of ferrochrome is dissolved in dilute sulfuric acid and then titrated against 13.10 cm3 of 0.100 mol dm-3 K2Cr2O7.
In the sample of ferrochrome, what is the percentage by mass of Fe?
43.90
7.31
4.39
43.23
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31 mark
A gas cylinder for a portable heater contains 13 kg of butane.
How many butane molecules are in the gas cylinder?
The Avogadro’s constant, L = 6.022 x 1023 mol-1
1.35 x 1026
2.69 x 1024
1.40 x 1026
3.72 x 10-22
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41 mark
Bromide ions are oxidised to bromine by lead (IV) chloride. Lead (IV) chloride is reduced to lead (II) chloride.
If 6.980 g of lead (IV) chloride is added to an excess of sodium bromide solution, what mass of bromine would be produced?
3.19 g
6.39 g
0.80 g
15.98 g
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51 mark
2.145 g of ethanedioic acid-2-water, (COOH)2·2H2O, was dissolved in water and diluted to 250 cm3 in a volumetric flask. A 25.0 cm3 portion was titrated with potassium manganate (VII) solution and 35.0 cm3 was required to oxidise the acid.
2MnO4- (aq) + 5C2O42- (aq) + 16H+ (aq) → 2Mn2+ (aq) + 10CO2 (g) + 8H2O (l)
What is the concentration of the potassium manganate (VII) solution in 25.0 cm3?
0.065 mol dm-3
0.055 mol dm-3
0.182 mol dm-3
0.019 mol dm-3
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61 mark
The glass containers X and Y are connected by a closed valve.
Flask Y contains ammonia, which occupies a volume of 1500 cm3. The tap is closed and there is a vacuum in flask X. The conditions of flask Y are 110 kPa and 320 K.
The tap is opened, meaning that ammonia starts to flow from flask Y and into flask X. The temperature decreases by 17 °C and the final pressure in both flasks is 65.0 kPa.
What is the total volume of flask X and Y in m3?
2.4 x 10-3
2.4
2.5 x 10-3
2.4 x 10-6
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71 mark
A block of solid iodine is put into a closed container at 100 kPa and left until completely sublimed to produce 1.3 dm3 of iodine vapour.
The empty container had a mass of 3.22 g and when iodine was added the mass increased to 9.57 g.
What is the approximate temperature of the iodine vapour?
(The gas constant R = 8.31 J K-1 mol-1)
313 K
0.6 K
415.0 K
625.8 K
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81 mark
Which of these substances contains the greatest number of atoms?
113 mg of chlorine
1.32 × 10-4 kg of sulfur
92.0 mg of ammonia
1.69 × 10−4 kg of methane
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91 mark
A 5.23 g sample of anhydrous potassium sulfate is dissolved in 250 cm3 of water in a volumetric flask.
What is the concentration in mol dm-3 of the potassium sulfate solution?
0.155
0.120
1.20 x 10-4
0.077
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101 mark
Which volume of oxygen gas, at room temperature and pressure, is required for complete combustion of 1.25 × 10−3 mol of propan-1-ol?
105 cm3
135 cm3
120 cm3
150 cm3
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11 mark
A hydrated carbonate of an unknown Group 1 metal has the formula X2CO3∙10H2O and is found to have a relative formula mass of 286.
What is the identity of the group 1 metal?
Na
K
Rb
Li
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21 mark
A volume of nitrogen gas, 3.00 dm3 measured under standard conditions, was reacted with a large volume of hydrogen gas, to produce ammonia. Only 15.0% of the nitrogen gas reacted to produce ammonia.
What mass of ammonia was made?
6.83 g
1.42 g
0.638 g
0.513 g
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31 mark
When heated magnesium nitrate, Mg(NO3)2, will decompose to magnesium oxide, nitrogen dioxide and oxygen as shown.
2Mg(NO3)2 (s) →2MgO (s) + 4NO2 (g) + O2 (g)
8.1 g of anhydrous magnesium nitrate is heated until no further reaction takes place.
What is the mass of nitrogen dioxide produced?
5.0 g
1.5 g
2.3 g
6.1 g
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41 mark
Hydrogen gas is produced when 1.45 g of lithium metal reacts with water at 298 K and 100 kPa.
2Li (s) + 2H2O (l) → 2LiOH (aq) + H2 (g)
Calculate the volume of hydrogen gas produced.
The gas constant, R = 8.31 J K-1 mol-1
2.60 m3
2602 m3
2.602 x 10-3 m3
1.260 x 10-3 m3
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51 mark
Solid fertilisers often contain the elements N, P and K in a ratio of 15 g: 30 g: 15 g per 100 g of fertiliser. It is recommended that the fertiliser is used at 19 g of fertiliser per 4 dm3 of water.
What is the concentration of nitrogen atoms in the solution?
0.423 mol dm-3
0.0509 mol dm-3
0.3 mol dm-3
0.75 mol dm-3
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61 mark
When heated, anhydrous calcium carbonate, CaCO3, will decompose into calcium oxide and carbon dioxide as shown.
CaCO3 (s) → CaO (s) + CO2 (g)
1.48 g of anhydrous calcium carbonate is heated until no further reaction takes place.
What mass of carbon dioxide dioxide is produced?
0.91 g
0.33 g
1.63 g
0.66 g
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71 mark
0.89 g of nitrogen gas is contained in a sealed vessel of volume of 7.0 × 10-3 m3 at a temperature of 305 K.
What is the pressure of the vessel in Pa?
The gas constant, R = 8.31 J K-1 mol-1
10752.9
11508.92
11.508
11224435.7
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81 mark
A compound has an Mr of 92, which contains 12 g of carbon, 2 g of hydrogen and 32 g of oxygen. What is the molecular formula of the compound?
C2H2O2
CH4O4
C2H4O2
C2H4O4
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91 mark
A student wanted to make up a 250 cm3 standard solution of anhydrous sodium carbonate, Na2CO3, with a concentration of 0.100 mol dm-3.
What is the mass of sodium carbonate they would need?
1.68 g
2.65 g
0.24 g
3.62 g
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101 mark
A coin contains 5.921% nickel by mass. If the coin weighs 9.97 g, how many nickel atoms are in the coin?
4.30 x 1022
3.01 x 1023
6.02 x 1025
6.02 x 1021
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