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Practice Paper 1 Stoichiometry Questions 1. A hydrocarbon contains 90% by mass of carbon. What is its empirical formula? A. CH2 B. C3H4 C. C7H10 D. C9H10 (Total 1 mark) 2. Copper can react with nitric acid as follows. 3Cu +_HNO3 _Cu(NO3)2 +_H2O + _NO What is the coefficient for HNO3 when the equation is balanced? A. 4 B. 6 C. 8 D. 10 (Total 1 mark) 3. 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) 4. 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 (Total 1 mark) 5. Which solution contains the smallest amount of H+ ions? A. 10.0 cm3 of 0.250 mol dm–3 HCl B. 20.0 cm3 of 0.250 mol dm–3 HCl C. 10.0 cm3 of 0.500 mol dm–3 HCl D. 10.0 cm3 of 0.250 mol dm–3 H2SO4 (Total 1 mark) 6. How many hydrogen atoms are contained in one mole of ethanol, C2H5OH? A. 5 B. 6 C. 1.0×1023 D. 3.6×1024 (Total 1 mark) 7. The percentage by mass of the elements in a compound is C = 72%, H = 12%, O = 16%. What is the mole ratio of C:H in the empirical formula of this compound? A. 1:1 B. 1:2 C. 1:6 D. 6:1 (Total 1 mark) 8. What amount of NaCl (in moles) is required to prepare 250 cm3 of a 0.200 mol dm–3 solution? A. 50.0 B. 1.25 C. 0.800 D. 0.0500 (Total 1 mark) 9. For which set of conditions does a fixed mass of an ideal gas have the greatest volume? Temperature Pressure A. low low B. low high C. high high D. high low (Total 1 mark) 10. Which of the following contains the greatest number of molecules? A. 1 g of CH3Cl B. 1 g of CH2Cl2 C. 1 g of CHCl3 D. 1 g of CCl4 (Total 1 mark) Practice Paper 1 Stoichiometry Answers 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. B C B D A D B D D A