Topic 1 multiple choice revision questions on quantitative chemistry 1. (M04) How many hydrogen atoms are contained in one mole of ethanol, C2H5OH? A. 5 C. 1.0 x 1023 B. 6 D. 3.6 x 1024 2. (M04) The percentage by mass of the elements in a compound is C = 72% H = 12% O = 16% What is the mole ratio C : H in the empirical formula of its compound? A. 1 : 1 B. 1 : 2 C. 1 : 6 D. 6 : 1 3. (M04) What is the coefficient for O2 (g) when the equation below is balanced? _ C3H8 (g) + _ O2 (g) A. 2 4. _ CO2 (g) B. 3 + _ H2O (g) C. 5 D. 7 According to the equation 2SO2 (g) + O2 (g) 2SO3 (g) what volume of air (20% O2) is required to react with 10 dm3 of SO2? A. 2 dm3 B. 5 dm3 C. 10 dm3 D. 25 dm3 5. (M03) Which of the following compounds has the greatest empirical formula mass? A. C6H6 6. B. C4H10 CaCO3 (s) CaO(s) C. C5H10 D. C2H6 + CO2 (g) When heated, CaCO3 (Mr = 100) decomposes as shown above. When 20 g of impure CaCO3 is heated, 0.15 moles of CO2 are obtained. What is the % purity of the CaCO3? A. 15 B. 25 C. 55 D. 75 7. Which compound has the highest percentage by mass of carbon? A. C2H2 B. C2H4 C. C3H8 D. C4H10 8. (N00) A certain compound has a relative molar mass of 88. A possible empirical formula for this compound is A. CH2 Topic 1 paper 1 revision 1 B. CH2O C. CH3O D. C2H4O 1 9. (N00) H2 + Cl2 2 HCl Hydrogen and chlorine react according to the equation above. What will the result of the reaction of 2.0 moles of H2 and 1.5 moles of Cl2? A. B. C. D. 3.5 mol of HCl. 1.5 mol of HCl and 0.5 mol of H2 2.0 mol of HCl and 0.5 mol of Cl2 3.0 mol of HCl and 0.5 mol of H2 10. (N00) 25.0 cm3 of sulfuric acid solution reacts with 36.2 cm3 of 0.225 mol dm-3 sodium hydroxide solution. The concentration of the acid is A. 36.2 x 0.225 25.0 B. 2 x 36.2 x 0.225 25.0 C. 36.2 x 0.225 2 x 25.0 D. 25.0 2 x 36.2 x 0.225 PbS (s) + O2 (g) PbO (s) + SO2 (g) 11. (N01) The reaction of lead (II) sulfide with oxygen at high temperatures is represented by the unbalanced equation above. What is the sum of the coefficients in the balanced equation? A. 4 B. 5 C. 8 D. 9 12. (N01) 8.0 of a pure compound contains 3.2g of sulfur and 4.8 g of oxygen. What is the empirical formula? A. SO B. SO2 C. SO3 D. S2O3 Zn (s) + Cu2+ (aq) Zn2+ (aq) + Cu (s) 13. (N01) Powdered zinc reacts with Cu2+ ions according to the equation above. What will be the result of adding 3.25g of Zn to 100 cm3 of 0.25 mol dm-3 CuSO4 solution? A. B. C. D. All the Cu2+ ions react and some solid zinc remains. All the Cu2+ ions react and no solid zinc remains. All the solid zinc reacts and Cu2+ ions remain. Neither solid zinc nor Cu2+ ions remain. 14. (N99) What is the empirical formula for a compound with the molecular formula C6H3(NO2)3? A. CHNO B. C2HNO2 C. (C2HNO2)3 D. C6H3N3O6 15. How many moles of CH4 are needed to obtain 6.0 x 1023 hydrogen atoms? A. ¼ Topic 1 paper 1 revision 1 B. 1 C. 2 D. 4 2 16. (N99) Arsenic, As4, reacts with oxygen to produce the oxide As4O10. What is the sum of the coefficients for the reactants in the balanced equation? __As4 + __O2 __ As4O10 A. 4 B. 5 C. 6 D. 7 17. (N99) What is the minimum number of grams of O2 (Mr = 32) required to burn 1.6 grams of CH4 (Mr = 16) according to the equation below? CH4 + 2O2 CO2 + 2H2O A. 1.6 B. 3.2 C. 6.4 D. 32 18. (N99) How many moles of HCl are in 25 cm3 of 0.2 mol dm-3 hydrochloric acid? A. 0.005 B. 0.008 C. 5 D. 8 19. (M99) Which sample has the greatest mass? A. 1.0 mol N2H4 B. 2.0 mol of N2 C. 3.0 mol of NH3 D. 25.0 mol H2 20. (M99) A compound contains 24 % magnesium, 28% silicon and 48% oxygen by mass. What is its empirical formula? A. MgSiO B. Mg2SiO C. MgSi2O D. MgSiO3 21. (M99) What is the mass in grams of one molecule of propanol, C3H7OH? B. 1.0 x 10-22 A. 60 C. 1.0 x 10 –23 D. 3.6 x 1025 22. Hydrogen sulfide, H2S, reacts with oxygen to form sulfur oxide and water as shown below: 2H2S + __O2 __SO2 + __H2O What is the coefficient of oxygen? A. 1 B. 2 C. 3 D. 6 23. Chloroethene, C2H3Cl, reacts with oxygen according to the equation below: 2C2H3Cl + 5O2 4CO2 + 2H2O + 2HCl How many moles of CO2 are produced when 3.0 mol of C2H3Cl and 3.0 mol of O2 are reacted? A. 2.4 Topic 1 paper 1 revision 1 B. 3.0 C. 4.0 D. 6.0 3 24. (N98) What mass in grams of solid silver chloride can be precipitated when 25 cm3 of 0.12 mol dm-3 sodium chloride is added to an excess of aqueous silver ions? A. 0.025 x 0.12 x (1/2) x (107.87 + 70.90) B. 0.025 x 0.12 x (107.87 + 35.45) C. 0.25 x 0.12 x (107.87 + 35.45) D. 25 x 0.12 x (107.87 + 35.45) 25. (N98) The percentage of nitrogen by mass in nitrogen dioxide, NO 2, is closest to which of the following? A. 20% B. 30 % C. 40% D. 50% 26. (N98) Aluminium reacts with hydrochloric acid to produce hydrogen gas according to the equation 2Al (s) + 6HCl (aq) 3H2 (g) + 2AlCl3 (aq) Which expression gives the number of moles of hydrogen that can be produced from 0.24 moles of Al and excess hydrochloric acid? A. 0.24 x 3/2 B. 0.24 x 2/3 C. 0.24 x 3/6 D. 0.24 x 6/2 27. (N98) Butane is used in cigarette lighters because it burns to form carbon dioxide and water as represented below: __C4H10 + __O2 __CO2 + __H2O What is the whole number coefficient for O2 when this equation is balanced correctly? A. 4 B. 5 C. 9 D. 13 28. A certain hydrocarbon has the empirical formula CH2 and a molar mass between 60 and 80. What is its most likely molecular formula? A. C4H8 B. C5H1O C. C6H12 D. C6H6 29. Which one of the following statements about CO2 is (are) correct? I. One mole of CO2 has a mass of 44.0 grams A. I only B. II only II One mole of CO2 contains 6.0 x 1023 atoms C. both I and II D. neither I nor II 30. If a 75 cm3 sample of vinegar has a concentration of 0.125 mol dm-3 of ethanoic acid, how many moles of ethanoic acid are present? A. 0.125 x 75.0 Topic 1 paper 1 revision 1 B. 0.125 x 75.0/1000 C. 0.125 x 1000/75.0 D. 1/0.125 x 75.0/1000 4 31. Which one of the following is both an empirical formula and a molecular formula? A. C12H22O11 B. C6H4Cl2 C. C4H8O2 D. C2H4 32. (M98) How many atoms are present in 0.1 mole of propyne, C3H4? A. 4.2 x 1022 B. 6.0 x 1022 C. 4.2 x 1023 D. 6.0 x 1023 33. (M98) What is the coefficient for O2 when the equation below is balanced? N2H4 + __O2 __NO2 + __H2O What is the whole number coefficient for O2 when this equation is balanced correctly? A. 2 B. 3 C. 4 D. 5 34. The balanced equation for the reaction of BaCl2 with Na3PO4 is 3BaCl2 (aq) + 2Na3PO4 (aq) Ba3(PO4)2 (s) + 6NaCl (aq) How many moles of NaCl could be produced from 2 moles of BaCl2 and excess Na3PO4? A. 1 B. 2 C. 3 D. 4 35. Excess Br2 is reacted with 40g of Ca to form CaBr2. How many grams of CaBr2 (Mr = 200) are formed if the actual yield is 50% of the theoretical? A. 50 B. 100 C. 150 D. 200 36. A 26.0 g sample of an unknown compound containing only carbon and hydrogen was burned in excess oxygen and 88.0g of CO2 were produced. What is a possible molecular formula of this compound? A. CH B. C2H2 C. C3H8 D. C6H6 37. The elemental analysis of a compound gave 39% potassium, 1% hydrogen, 12% carbon and 48% oxygen by mass. How many oxygen atoms appear in the empirical formula of this compound? A. 1 B. 2 C. 3 D. 4 38. All of the following statements are consistent with the concept of a mole of substance except A. B. C. D. one mole of sodium contains 6.02 x 1023 sodium atoms one mole of carbon-12 atoms has a mass of 12.0 grams one mole of chlorine gas contains 6.02 x 1023 chlorine molecules one mole of sodium chloride contains 6.02 x 1023 ions Topic 1 paper 1 revision 1 5 39. A sample of ethane (C2H6) contains 2 x 1022 carbon atoms. How many hydrogen atoms does it contain? A. 3 x 1022 B. 6 x 1022 C. 12 x 1022 D. 6 x 1023 40. The balanced equation for the oxidation of ammonia by air is: 4NH3 (g) + 5O2 (g) 4NO (g) + 6H2O (l) How many moles of oxygen gas would be required to react with 20 moles of ammonia? A. 10 B. 20 C. 25 D. 30 41. Equal masses of oxygen and hydrogen gases are reacted in a closed vessel according to the equation: 2H2 (g) + O2(g) 2H2O (l). After the reaction is complete, the container will contain A. water and oxygen only C. water only Topic 1 paper 1 revision 1 B. water and hydrogen only D. water, hydrogen and oxygen 6 Answers 1 2 3 4 5 6 7 D B C D B D A 8 9 10 11 12 13 14 D D C D C A B 36 41 B B 37 C Topic 1 paper 1 revision 1 15 16 17 18 19 20 21 38 A C C A B D B D 22 23 24 25 26 27 28 39 C A B B A D B B 29 30 31 32 33 34 35 40 A B A C B D B C 7