1 Topic 01 (Atom & Stoichiometry) (A-Level) 1. In the radioactive decay of an isotope of lead to an isotope of bismuth, a particle 0 X is emitted. Which particle is 0 X ? 1 1 A electron B ion C neutron D proton s02/q1 2. As a simplification, an adult human can be considered to have a daily diet of 1.80 kg of carbohydrate (empirical formula CH2O). Which mass of carbon dioxide does a person produce each day if all the carbohydrate eaten is digested and oxidised? A 0.267 kg B 0.800 kg C 1.32 kg D 2.64 kg s02/q2 9. A pure hydrocarbon is used in bottled gas for cooking and heating. When 10 cm3 of the hydrocarbon is burned in 70 cm3 of oxygen (an excess), the final gaseous mixture contains 30 cm 3 of carbon dioxide and 20 cm3 of unreacted oxygen. All gaseous volumes were measured under identical conditions. What is the formula of the hydrocarbon? A C2H6 B C3H6 C C3H8 D C4H10 s05/q1 3. The diagram shows the mass spectrum of a sample of naturallyoccurring copper. 10. On collision, airbags in cars inflate rapidly due to the production of nitrogen. The nitrogen is formed according to the following equations. 2NaN3 2Na + 3N2 10Na + 2KNO3 K2O + 5Na2O + N2 How many moles of nitrogen gas are produced from 1 mol of sodium azide, NaN3? A 1.5 B 1.6 C 3.2 D 4.0 s05/q2 11. N2O4 is a poisonous gas. It can be disposed of safely by reaction with sodium hydroxide. N2O4(g) + 2NaOH(aq) NaNO3(aq) + NaNO2(aq) + H2O(l) What is the minimum volume of 0.5 mol dm–3 NaOH(aq) needed to dispose of 0.02 mol of N2O4? A 8 cm3 B 12.5 cm3 C 40 cm3 D 80 cm3 s06/q1 What is the relative atomic mass of this copper? A 63.3 B 63.5 C 63.6 D 64.0 s02/q3 12. A sample of chlorine containing isotopes of mass numbers 35 and 37 was analysed in a mass-spectrometer.How many peaks corresponding toCl 2 were recorded? A2 B3 C4 D5 s06/q2 4. The use of the Data Booklet is relevant to this question. What is the number of molecules in 500 cm3 of oxygen under room conditions? A 1.25 x 1022 B 1.34 x 1022 C 3.0 x 1022 D 3.0 x 1026 s03/q1 13. The isotopic composition of an element is indicated below. 5. In the preparation of soft margarine, glyceryl trieleostearate is suitably hydrogenated so that, on average, one of its side-chains is converted into the CH3(CH2)4CH=CHCH2CH=CH(CH2)7CO2 residue and two side-chains are converted into the CH3(CH2)7CH=CH(CH2)7CO2 residue. How many moles of hydrogen are required to convert one mole of glyceryl trieleostearate into the soft margarine? A4 B5 C6 D9 s03/q2 What is the relative atomic mass of the element? A 10.2 B 10.5 C 10.8 D 11.0 s07/q1 6. Which of these samples of gas contains the same number of atoms as 1g of hydrogen (Mr : H2, 2)? A 22 g of carbon dioxide (Mr : CO2, 44) B 8 g of methane (Mr : CH4, 16) C 20 g of neon (Mr : Ne, 20) D 8 g of ozone (Mr : O3, 48) s04/q1 14. Use of the Data Booklet is relevant to this question. Oxides of nitrogen are pollutant gases which are emitted from car exhausts. In urban traffic, when a car travels one kilometre, it releases 0.23 g of an oxide of nitrogen NxOy, which occupies 120 cm3. What are the values of x and y? (Assume 1 mol of gas molecules occupies 24.0 dm 3.) A x = 1, y = 1 B x = 1, y = 2 C x = 2, y = 1 D x = 2, y = 4 s07/q2 7. Self-igniting flares contain Mg3P2. With water this produces diphosphane, P2H4, which is spontaneously flammable in air. Which equation that includes the formation of diphosphane is balanced? A Mg3P2 + 6H2O 3Mg(OH)2 + P2H4 B Mg3P2 + 6H2O 3Mg(OH)2 + P2H4 + H2 C 2Mg3P2 + 12H2O 6Mg(OH)2 + P2H4 + 2PH3 D 2Mg3P2 + 12H2O 6Mg(OH)2 + 3P2H4 s04/q2 15. In the Basic Oxygen steel-making process the P4O10 impurity is removed by reacting it with calcium oxide. The only product of this reaction is the salt calcium phosphate, Ca3(PO4)2. In this reaction, how many moles of calcium oxide react with one mole of P4O10? A1 B 1.5 C3 D6 s08/q1 8. Use of the Data Booklet is relevant to this question. Most modern cars are fitted with airbags. These work by decomposing sodium azide to liberate nitrogen gas, which inflates the bag. 2NaN3 3N2 + 2Na A typical driver’s airbag contains 50 g of sodium azide. Calculate the volume of nitrogen this will produce at room temperature. A 9.2 dm3 B 13.9 dm3 C 27.7 dm3 D 72.0 dm3 s04/q3 16.Use of the Data Booklet is relevant to this question. A typical solid fertiliser for use with household plants and shrubs contains the elements N, P, and K in the ratio of 15 g : 30 g :15 g per 100 g of fertiliser. The recommended usage of fertiliser is 14 g of fertiliser per 5 dm3 of water. What is the concentration of nitrogen atoms in this solution? A 0.03 mol dm–3 B 0.05 mol dm–3 C 0.42 mol dm–3 D 0.75 mol dm–3 s08/q2 Zafar Iqbal Ch. How many molecules of an amino acid (Mr = 200) would this be? A9 B 200 C 1800 D 360 000 w03/q1 w04/q2 22.82 C 1.] 28. After cooling to room temperature. Which ion has more electrons than protons and more protons than neutrons? A D– B H3O+ C OD– D OH– w05/q2 The increases in mass of the collecting vessels P and Q of the apparatus are MP and MQ.0 cm3 of bleach is treated with an excess of aqueous H2O2. lead(II) oxide. A 65 C 65. respectively.2 Topic 01 (Atom & Stoichiometry) (A-Level) 17. When it is completely burned in air. CH3SH. as its active ingredient. which burns as follows. The concentration of NaClO in the bleach can be determined by reacting a known amount with aqueous hydrogen peroxide.0350 mol of oxygen gas is given off.700 mol dm–3 –3 C 0. CON2H4. One of the most important chemical species responsible for the removal of ozone from the stratosphere is a free radical of chlorine.40 mol dm–3 19. The petrol additive tetraethyl-lead(IV). Unnilpentium is an artificial element.2 D 2. NaClO. Unp is 262. 0. What is the ratio MP / MQ? A 0. In leaded petrol there is an additive composed of lead. A sample of the hydrocarbon C6H12 is completely burned in dry oxygen and the product gases are collected as shown. 18. one of which is methanethiol. Analytical chemists can detect very small amounts of amino acids. is now banned in many countries. NaClO(aq) + H2O2(aq) NaCl(aq) + O2(g) + H2O(l) When 25. H2O2. . 260 105 B The atom X is an isotope of 262 105 262 105 Unp.4 w03/q3 Zafar Iqbal Ch. Use of the Data Booklet is relevant to this question. y and z in a balanced equation? x y z A 1½ 2 1¼ B 2 4 3 C 3 4 3½ D 3 4 3 w04/q1 w02/q1 20.2% D 30. One of its isotopes is Which of the following statements is correct? A 262 105 262 105 Unp.Use of the Data Booklet is relevant to this question.5 D 27 w05/q1 29.55% B 13.1 % C 26. A household bleach contains sodium chlorate(I).875 mol dm D 1. C.66 21.5 B 11 C 13.Use of the Data Booklet is relevant to this question. w03/q4 25. Granular urea. converting it into harmless nitrogen.75 × 10–4 mol dm–3 B 0. What does 35Cl contain? protons neutrons electrons A 17 18 16 B 17 18 17 C 18 17 17 D 18 17 18 w02/q2 26. 35Cl . 1 . What volume of gas was absorbed by the alkali? A 15 cm3 B 20 cm3 C 30 cm3 D 40 cm3 s09/q2 C There are 262 neutrons in D The proton number of 262 105 Unp. Pb(C2H5)4. What is the percentage by mass of phosphorus in the fertiliser? A 6. 2CON2H4 + x NO2 2CO2 + y H2O + z N2 What are the values of x. The diagram shows the mass spectrum of a sample of zinc.0% ‘P2O5 soluble in water’. down to 3 x10–21 mol. the residual gas was passed through aqueous potassium hydroxide. Use the data to calculate the relative atomic mass of the sample. This compound contains 29.41 B 0.19 % hydrogen by mass. Unp has a nucleon number of 105. [Ar : H. 16. What is the value of x in the empirical formula PbC8HX? A5 B6 C 16 D 20 s09/q1 24.5 B 65. The foul smell that skunks spray is due to a number of thiols. carbon and hydrogen only.25 D 65. A mixture of 10 cm3 of methane and 10 cm3 of ethane was sparked with an excess of oxygen. How many moles of oxygen are required to burn one mole of Pb(C2H5)4? A 9. A garden fertiliser is said to have a phosphorus content of 30.7 % carbon and 6. What is the concentration of NaClO in the bleach? A 8. can be used to remove NO2 from the flue gases of power stations. CO2 and H2O are formed. CH3SH + 3O2 CO2 + SO2 + 2H2O A sample of 10 cm3 of methanethiol was exploded with 60 cm3 of oxygen. 12 . What would be the final volume of the resultant mixture of gases when cooled to room temperature? A 20 cm3 B 30 cm3 C 50 cm3 D 70 cm3 w04/q3 23. O.0% w03/q2 27. 0 × 1018 B 1.An element X consists of four isotopes. A 50 cm3 sample of water containing dissolved calcium sulphate was passed through the ionexchange resin. The resulting acidic solution collected in the flask required 25 cm 3 of 1. What is the molecular formula of the hydrocarbon? A C2H4 B C2H6 C C4H4 D C4H8 w09/q2 33.75 D 92. of residual gas measured again at room temperature and pressure.3 Topic 01 (Atom & Stoichiometry) (A-Level) 30. TiO2.0 × 10–2 mol dm–3 potassium hydroxide for complete neutralisation.0 tonnes B 12. What is the relative atomic mass of X? A 91.8 × 1019 C 1.1 × 1022 w07/q1 38. 0.2 × 1021 D 4. Each calcium ion in the sample was exchanged for two hydrogen ions. Carbon disulphide vapour burns in oxygen according to the following equation. x.2 g of carbon dioxide and 14.30 C 91. In forming ionic compounds. . When a sports medal with a total surface area of 150 cm2 was evenly coated with silver. After measuring the volume of gas remaining. The first stage in the manufacture of nitric acid is the oxidation of ammonia by oxygen. What is the maximum amount of TiO2 obtainable from 19.0 × 10–2 mol dm–3 C 2. using electrolysis.5 × 10–3 mol dm–3 B 1.0 tonnes D 17. under such conditions that carbon disulphide was gaseous. Use of the Data Booklet is relevant to this question. What were the measured volumes? volume of gas volume of gas after after burning / cm3 adding NaOH(aq) / cm3 A 30 0 B 30 20 C 50 20 D 50 40 w08/q2 37. wNH3(g) + xO2(g) yNO(g) + zH2O(g) Which values for w. What was the concentration of the calcium sulphate in the original sample? A 2. Titanium(IV) oxide.0 tonnes of the ore ilmenite. Which graph represents the results that would be obtained? 34. The amount of calcium ions in a sample of natural water can be determined by using an ion-exchange column as shown in the diagram. elements generally form an ion with the electronic structure of a noble gas. The mass spectrum of X is shown in the diagram. All measurements were made at the same temperature and pressure. Use of the Data Booklet is relevant to this question.00 B 91. Use of the Data Booklet is relevant to this question.0 × 10–2 mol dm–3 w06/q1 36. CS2(g) + 3O2(g) CO2(g) + 2SO2(g) A sample of 10 cm3 of carbon disulphide was burned in 50 cm3 of oxygen. y and z are needed to balance the equation? w x y z A 4 5 4 6 B 4 6 4 5 C 5 6 5 4 D 6 5 6 4 w07/q3 35.7 tonnes C 14.0 × 10–2 mol dm–3 D 4.200 mol of a hydrocarbon undergo complete combustion to give 35. its mass increased by 0. Each is then burned and the total volume. is brilliantly white and much of the oxide produced is used in the manufacture of paint. the product was treated with an excess of aqueous sodium hydroxide and the volume of gas measured again. V.216 g. Which ion does not have a noble gas electronic structure? A I– B Rb+ C Sn2+ D Sr2+ w07/q2 Zafar Iqbal Ch.4 g of water as the only products.7 tonnes w08/q1 w06/q4 31. How many atoms of silver were deposited per cm 2 on the surface of the medal? A 8. FeTiO3? A 10.00 w09/q1 32. Samples of 10 cm3 of each of the first four members of the alkane series are separately mixed with 70 cm 3 of oxygen. s04/q31 41. Which compounds have the empirical formula CH2O? 1 methanal 2 ethanoic acid 3 methyl methanoate w02/q31 s08/q31 s09/q31 45. s07/q31 42. 1 mol of an organic compound X was found to require 2. 3 It has a different number of neutrons from the atoms of other isotopes of cobalt. On a scale in which the mass of a 12C atom is 12 the relative molecular mass of a particular sample of chlorine is 72. Which pairs of compounds have the same empirical formula? 1 ethane and ethane 2 ethene and cyclohexane 3 cyclohexane and oct-1-ene s02/q31 40. Which properties of the atoms in this sample are always the same? 1 radius 2 nucleon number 3 isotopic mass 44. Which compounds could be X? 1 C2H5OH 2 C2H2 3 CH3CHO 43. 2 It has 43 protons. .4 Topic 01 (Atom & Stoichiometry) (A-Level) SECTION B 39. The isotope cobalt-60 ( 60 Co ) is used to destroy cancer cells in the 27 human body. Which statements about an atom of cobalt-60 are correct? 1 It contains 33 neutrons. For complete combustion. The relative molecular mass of a molecule of chlorine is 72. The technetium–99 isotope (99Tc) is radioactive and has been found in lobsters and seaweed adjacent to nuclear fuel reprocessing plants. Use of the Data Booklet is relevant to this question.5 mol of molecular oxygen. 2 Its nucleus has a relative charge of 27+. 3 It has 99 nucleons. Which properties of the atoms in this molecule are the same? 1 radius 2 nucleon number 3 relative isotopic mass w05/q31 Zafar Iqbal Ch. Which statements are correct about an atom of 99Tc? 1 It has 13 more neutrons than protons. ................................................................................................. ............ ........... O2 → Sb4O6 + ..... (a) State the full electronic configuration of phosphorus......... but now its main use is to strengthen lead alloys................5.................................................. Compounds of phosphorus have many uses in everyday life..................................500 mol dm–3 H3PO4 and an excess of aqueous sodium hydroxide...... (iii) Calculate the volume of carbon dioxide.............. has been known for about 6000 years............ O.............................................. Chlorine has two isotopes................................. .. is used in the manufacture of phosphate fertilisers...... Calculate the molecular formula of A. e.... fertilisers........ [2] (d) Use your answer to (c) to explain why chlorine has a relative atomic mass of 35........................... [2] (c) Use the relative heights of the peaks to determine the proportions of the two isotopes of chlorine.................[1] (b) In a mass spectrometer some hydrogen chloride molecules will split into atoms...................................... Antimony is produced in a two-stage process from stibnite........................................................... [4] w02/q3 2.g........... The oxide is then reduced with carbon......... Na3PO4................ Antimony..... It has an Mr of 72..........5 Topic 01 (Atom & Stoichiometry) (A-Level) THEORY SECTION 1............[1] (b) Phosphoric acid............. .... 3.............. Sb2S3..... [1] [Total : 6] s03/q1 ................ has the following composition by mass..... P4S3.............................SO2 (i) Balance the above equation................... ............... Explain simply how you obtained your answer.......[1] (c) The salt sodium phosphate................ measured at room temperature and pressure............... . (i) What particle is responsible for the peak at mass 35? ........ matches and in water softeners........ A compound.7%.................................................. H... (i) Write the equation for the complete neutralisation of phosphoric acid with aqueous sodium hydroxide..................0 cm 3 of 0...... 1 [3] 5............................................... ...... [2] s03/q6 4............... (i) Construct an equation for this reaction.............. A............... is a water-softening agent... 22........................[4] [Total : 9] s04/q2 Zafar Iqbal Ch........................ Sodium phosphate was prepared from 50........2%. (iii) Use your equation in (c)(i) to calculate how many moles of sodium hydroxide are required.................. H3PO4..... ....... 2Sb2S3 + . On striking a match..... this compound burns........... C.............. The mass spectrum of HCl is given............... Sb4O6 + 3C → 4Sb + 3CO2 (ii) What is the oxidation number of antimony in Sb4O6? ........................... (a) Define an isotope in terms of its sub-atomic particles. is used in small amounts in the tip of a match....1%.. It is present in many ancient forms of bronze............ The hydrogen involved here is the isotope 1H only....................... Construct an equation for the reaction of each oxide with water. Deduce the oxidation number of phosphorus in H3PO4...................... (ii) What particle is responsible for the peak at mass 38? ....................... 11............................... 66........... ..... (ii) Both oxides formed in (i) dissolve in water to give acidic solutions............. (ii) How many moles of H3PO4 were used? ................................ The ore is first roasted in oxygen to form the oxide........ Phosphorus sulphide. that would be produced by the processing of 10 moles of Sb2S3. a sulphide ore..... Sb................................................... .................... (i) Use the Data Booklet to calculate how many moles of NH3(g) were dissolved............ (ii) By using the data above........ (ii) Mr ............................................... Use the Data Booklet to complete the table below to show the atomic structure of 56Fe and of 59Co........... to ................... 1................................[2] (b) The most common isotope of iron is 56Fe...............65 g of H2S? Give your answer to two decimal places.......................................................................... Iron has three main naturally occurring isotopes................ isotope mass 54 56 57 % by mass 5... Hydrogen sulphide burns with a blue flame in an excess of oxygen to form sulphur dioxide and water........... ......... [5] s05/q2 8...................... measured at room temperature and pressure... (ii) What is the change in the oxidation number of sulphur in this reaction? from ............................................6 Topic 01 (Atom & Stoichiometry) (A-Level) 6...................... calculate the relative atomic mass of iron to three significant figures............................. .................................................................... Two such examples are citronellol and geraniol........... [5] [Total: 10] s05/q1 9........ the only naturally occurring isotope of cobalt is 59Co......... number of isotope 56 protons Neutrons electrons Fe Co 59 Zafar Iqbal Ch..................... (i) Molecular formula ...................... (c) A sample of iron has the following isotopic composition by mass. (iii) What volume of oxygen................ Mr.... Some perfumes and scents of flowers and fruit contain compounds which are structural isomers......[2] w04/q4 .......................20dm3 of ammonia gas were dissolved in water to form 200 cm 3 of aqueous alkali at room temperature and pressure.......... ....................................................................................... is required for the complete combustion of 8. (a) Explain the meaning of the term isotope.......50mol dm –3 sulphuric acid that is required to neutralize the 200 cm3 of aqueous ammonia........................................... ............. (ii) Write the equation for the neutralisation of aqueous ammonia by dilute sulphuric acid........................... ...... (i) Write a balanced equation for the complete combustion of H2S................................................................68 2................................................ ............. cobalt has one.............. Iron and cobalt are adjacent elements in the Periodic Table.....84 91.............................................................. (iii) Calculate the volume of 0..... Confirm that citronellol and geraniol are isomers by calculating their molecular formula and their relative molecular mass................................................................... .............................................17 (i) Define the term relative atomic mass................... [3] s04/q3 7...................................................... ................................. ................ Iron and cobalt are adjacent elements in the Periodic Table.................................7 Topic 01 (Atom & Stoichiometry) (A-Level) Use the Data Booklet to complete the table below to show the atomic structure of 56Fe and of 59Co......... Iron has three main naturally occurring isotopes.................. number of isotope 56 protons Neutrons electrons Fe Co 59 6..... Hydrogen sulphide burns with a blue flame in an excess of oxygen to form sulphur dioxide and water............................................................................................. isotope mass 54 56 57 % by mass (ii) Write the equation for the neutralisation of aqueous ammonia by dilute sulphuric acid......................................................... 1....... Mr.......... (i) Molecular formula . ...... measured at room temperature and pressure....... ............ the only naturally occurring isotope of cobalt is 59Co...................... (ii) By using the data above................ (iii) Calculate the volume of 0........... Some perfumes and scents of flowers and fruit contain compounds which are structural isomers............................................................................... (a) Explain the meaning of the term isotope..... ........ (c) A sample of iron has the following isotopic composition by mass.......... calculate the relative atomic mass of iron to three significant figures.............................................................65 g of H2S? Give your answer to two decimal places........50mol dm–3 sulphuric acid that is required to neutralize the 200 cm3 of aqueous ammonia.............. [5] [Total: 10] Confirm that citronellol and geraniol are isomers by calculating their molecular formula and their relative molecular mass..................... ............... [5] 8................................. (iii) What volume of oxygen..................... is required for the complete combustion of 8................................... ............. (i) Use the Data Booklet to calculate how many moles of NH3(g) were dissolved.......................................................................................... .....84 91................................................................................. to ...........20dm3 of ammonia gas were dissolved in water to form 200 cm3 of aqueous alkali at room temperature and pressure................17 (i) Define the term relative atomic mass......[2] (b) The most common isotope of iron is 56Fe....................... [3] s04/q3 7.... (i) Write a balanced equation for the complete combustion of H2S...................... s05/q2 Zafar Iqbal Ch.............................................. Two such examples are citronellol and geraniol............................................. ............................. (ii) Mr ........................ cobalt has one............ ...................................................... (ii) What is the change in the oxidation number of sulphur in this reaction? from . 5..............................................[2] w04/q4 s05/q1 9......................... ...............68 2........