1. Chemistry Raymond Chang 10 th edition Chapter 3 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2. Question 1 A mole of carbon (molar mass about 12) contains fewer atoms than a mole of oxygen (molar mass about 16). A) True B) False

3. Question 2 One atom of oxygen weighs about 16 g. A) True B) False

4. Question 3 One atom of carbon weighs about 12 amu. A) True B) False

5. Question 4 One mole of carbon weighs about 12 g. A) True B) False

6. Question 5 If the ratio of moles of carbon to hydrogen in a hydrocarbon compound is found by experiment to be 1.5002:3.0005 then the most likely empirical formula is A) C 2 H 3. B) C 15 H 30. C) C 2 H 6. D) CH 2.

7. Question 6 If 1.00 g of a compound composed of hydrogen and oxygen is found to contain 0.94 g oxygen, then which of the following molecular formulas is likely? A) H 2 O B) H 2 O 2 C) HO 2 D) None of the above

8. Question 7 Which of the following chemical equations represents the decomposition of solid calcium carbonate to yield oxygen gas and solid calcium oxide? 1. A) CaCO 2(s) → CaO (s) + O 2(g) 2. B) CaCO 3(s) → CaO (s) + O 2(l) 3. C) CaCO 3(s) → CaO (s) + O (g) 4. D) CaCO 3(s) → CaO (s) + O 2(g)

9. Question 8 How many moles of Zn would be required to produce 4 moles of hydrogen gas using the following reaction? Zn (s) + 2HCl (aq) → ZnCl 2(aq) +H 2(g) A) 8 mol B) 4 mol C) 2 mol D) 1 mol

10. Question 9 How many moles of Zn would be required to completely react with 1 mole of HCl using the following reaction? Zn (s) + 2HCl (aq) → ZnCl 2(aq) +2H 2(g) A) 0.5 mol B) 1 mol C) 2 mol D) 4 mol

11. Question 10 How much zinc chloride could be made from one mole of Zn and 1 mole of HCl if the reaction is? Zn (s) + 2HCl (aq) → ZnCl 2(aq) +H 2(g) A) 1 mol B) 2 mol C) 0.5 mol D) 0 mol since the molar ratio is incorrect

12. Question 11 Avogadro's number represents A) the number of particles in a mole. B) the ratio between 1 g and 1 amu. C) the ratio between the molar mass of NaCl and the molecular mass of NaCl. D) the ratio between the molar mass of Cu and the average atomic mass of Cu. E) all of the above.

13. Question 12 Which of the following statements is/are true? A) 1.000 mol sodium weighs 22.99 g B) 1.000 mol sodium chloride contains 1.2044x10 24 ions C) 1.0 mol of aluminum chloride contains twice as many ions as 1.0 mol of sodium chloride D) All of the above E) None of the above

14. Question 13 What is the mass of 1.0 kmol of water? A) 18 g B) 18 amu C) 18 kg D) 1000 amu E) None of the above

15. Question 14 The mass % of manganese in potassium permanganate is A) 24.75 %. B) 34.77 %. C) 40.51 %. D) 27.87 %. E) None of the above.

16. Question 15 The empirical formula of mercurous chloride is A) Hg 2 Cl 2. B) HgCl. C) HgCl 2. D) Hg 2 Cl. E) (HgCl)n.

17. Question 16 The mass percent composition of an oxoacid of sulfur is : 1.75 % H, 56.14 % S, 42.11 % O. Determine the empirical formula of the acid. A) H 2 SO 4 B) H 2 SO 3 C) H 2 S 2 O 3 D) H 2 SO 5 E) HSO 1.5

18. Question 17 The chemical equation (NH 4 ) 2 Cr 2 O 7 → Cr 2 O 3 + N 2 + 4H 2 O tells us the following: A) From 1 mol of (NH 4 ) 2 Cr2O7 we get 1 mol of Cr 2 O 3 B) From 1 mol of (NH 4 ) 2 Cr 2 O 7 we get 1 mol of N 2 C) From 1 mol of (NH 4 ) 2 Cr 2 O 7 we get 4 mol of H 2 O D) All of the above E) None of the above

19. Question 18 A balanced chemical equation tells us: A) The ratios of moles of reactants that participate in the reaction. B) The ratios of moles of products that are formed in the reaction. C) That we can calculate the amount of a reactant needed based on how much of a specific product we need. D) That we can calculate the amount of product formed based on the amount of one reactant and excess of other reactants. E) All of the above.

20. Question 19 Given the reaction: SO 3 (g) + H 2 O(g) → H 2 SO 4 (l), calculate the amount of sulfur trioxide necessary to produce 196 kg sulfuric acid assuming 100% yield. A) 80 kg B) 80 g C) 160 g D) 160 kg E) None of the above

21. Question 20 Given the reaction: SO 3 (g) + H 2 O(g) → H 2 SO 4 (l), which proceeds with a yield of 85.0%, calculate the amount of sulfuric acid that is formed when 120. kg sulfur trioxide is mixed with 32.4 kg water. A) 147 kg B) 125 kg C) 176 kg D) 150 kg E) None of the above

22. Answer Key – Chapter 3 1. B 2. B 3. A 4. A 5. D 6. B 7. D 8. C 9. A 10. C 11. E 12. D 13. C 14. B 15. B 16. C 17. D 18. E 19. D 20. B