IB Stoichiometry (Topic 1) Revision SL + HL EQUATIONS (data booklet) CALCULATING MOLAR MASS 1. What amount (in moles) is present in 2.0 g of sodium hydroxide, NaOH? A. 0.050 B. 0.10 C. 20 D. 80 (Total 1 mark) 2. CALCULATING NUMBER OF PARTICLES 3. What amount of oxygen, O2, (in moles) contains 1.8×1022 molecules? A. 0.0030 B. 0.030 C. 0.30 D. 3.0 4. EMPIRICAL AND MOLECULAR FORMULA 5. Which compound has the empirical formula with the greatest mass? A. C2H6 B. C4H10 C. C5H10 D. C6H6 6. An organic compound, A, containing only the elements carbon, hydrogen and oxygen was analysed. (a) A was found to contain 54.5% C and 9.1% H by mass, the remainder being oxygen. Determine the empirical formula of the compound. (3) 7. REACTING MASS CALCULATIONS 8. Lithium hydroxide reacts with carbon dioxide as follows. 2LiOH + CO2 → Li2 CO3 + H2O What mass (in grams) of lithium hydroxide is needed to react with 11 g of carbon dioxide? A. 6 B. 12 C. 24 D. 48 (Total 1 mark) 9. PERCENTAGE YIELD LIMITING REAGENTS 10. 0.600 mol of aluminium hydroxide is mixed with 0.600 mol of sulfuric acid, and the following reaction occurs: 2Al(OH)3 (s) + 3H2SO4 (aq) → Al 2 (SO4)3(aq) + 6H2O(l) (a) Determine the limiting reactant. ..................................................................................................................................... ..................................................................................................................................... .....................................................................................................................................(2) (b) Calculate the mass of Al 2(SO4)3 produced. ..................................................................................................................................... ..................................................................................................................................... .....................................................................................................................................(2) (c) Determine the amount (in mol) of excess reactant that remains. ..................................................................................................................................... ...................................................................................................................................(1) 11. Copper metal may be produced by the reaction of copper(I) oxide and copper(I) sulfide according to the below equation. 2Cu2O + Cu2S → 6Cu + SO2 A mixture of 10.0 kg of copper(I) oxide and 5.00 kg of copper(I) sulfide was heated until no further reaction occurred. (a) Determine the limiting reagent in this reaction, showing your working. .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... (3) (b) Calculate the maximum mass of copper that could be obtained from these masses of reactants. .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... (2) AVOGADRO’S LAW AND GASES 12. Propane and oxygen react according to the following equation. C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(g) Calculate the volume of carbon dioxide and water vapour produced and the volume of oxygen remaining, when 20.0 dm3 of propane reacts with 120.0 dm3 of oxygen. All gas volumes are measured at the same temperature and pressure. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. .............................................................................................................................................. (Total 3 marks) THE IDEAL GAS LAW 13. Which change in conditions would increase the volume of a fixed mass of gas? Pressure /kPa Temperature /K A. Doubled Doubled B. Halved Halved C. Doubled Halved D. Halved Doubled 14. (actually second half of Q6) (b) A 0.230 g sample of A, when vaporized, had a volume of 0.0785 dm3 at 95°C and 102 kPa. Determine the relative molecular mass of A. (3) (c) Determine the molecular formula of A using your answers from parts (a) and (b). ................................................................................................................................... ................................................................................................................................... (1) 15. THE MOLAR CONCENTRATION OF SOLUTIONS 16. What volume (in dm3) of 0.30 mol dm–3 NaCl solution can be prepared from 0.060 mol of solute? A. 0.018 B. 0.20 C. 0.50 D. 5.0 (Total 1 mark) TITRATION CALCULATIONS 17. Determine the volume (in cm3) of 1.50 mol dm–3 hydrochloric acid that would react with exactly 1.25 g of calcium carbonate. CaCO3 + 2HCl → CaCl2 + CO2 + H2O ………………………………………………………………………………………….. ………………………………………………………………………………………….. …………………………………………………………………………………………..(3) 18. An unknown metal carbonate reacts with hydrochloric acid according to the following equation. M2CO3(aq) + 2HCl(aq) → 2MCl(aq) + CO2(g) + H2O(l) A 3.44 g sample of M 2CO3 was dissolved in distilled water to make 250 cm3 of solution. A 25.0 cm 3 portion of this solution required 33.2 cm3 of 0.150 mol dm–3 hydrochloric acid for complete reaction. (i) Calculate the amount, in moles, of HCl in 33.2 cm3 of 0.150 mol dm–3 hydrochloric acid. Give your answer to 3 significant figures. ............................................................................................................. (1) (ii) Calculate the amount, in moles, of M2CO3 that reacted with this amount of HCl. Give your answer to 3 significant figures. ............................................................................................................. (1) (iii) Calculate the amount, in moles, of M2CO3 in the 3.44 g sample. Give your answer to 3 significant figures. ............................................................................................................. (1) (iv) Calculate the relative formula mass, Mr, of M2CO3 Give your answer to 1 decimal place. ............................................................................................................. (1) (v) Hence determine the relative atomic mass, Ar, of the metal M and deduce its identity. Ar of M ................................................................................................. Identity of M ........................................................................................ (2)
