1. MOL Concept Warmups

2. 1. The gram-formula mass of a compound is 48 grams. The mass of 1.0 mole of this compound is – A. 1.0 g B. 4.8 g C. 48 g D. 480 g

3. Answer C is the correct answer.

4. 2. How many moles are in 59.6 grams of BaSO 4 ? A) 0.256 mole B) 3.91 moles C) 13.9 moles D) 59.6 moles

5. Answer A is the correct answer.

6. 3. How many molecules are contained in 55.0 grams of H2SO4? A) 0.561 molecules B) 3.93 molecules C) 3.38 X 10 23 molecules D) 2.37 X 10 24 molecules

7. Answer C is the correct answer.

8. 4. If a sample of magnesium has a mass of 60. grams, how many moles of magnesium does the sample contain? A) 1.1 moles B) 1.2 moles C) 2.0 moles D) 2.5 moles

9. Answer D is the correct answer.

10. 5. Analysis shows a compound to be, by mass, 43.8% N, 6.2% H, and 50.0% O. Which is a possible molecular formula for the compound? A) NH 4 NO 2 B) NH 4 NO 3 C) NH 3 OH D) N 2 OH

11. Answer A is the correct answer.

12. 6. A compound has an empirical formula of CH 2 O and a molecular mass of 180 grams. What is the compound’s molecular formula? A) C 3 H 6 O 3 B) C 6 H 12 O 6 C) C 6 H 11 O 7 D) C 12 H 22 O 11

13. Answer B is the correct answer.

14. 7. What is the percent by mass of iron in the compound Fe 2 O 3 ? A) 70 % B) 56 % C) 48% D) 30 %

15. Answer A is the correct answer.

16. 8. What is the percent composition by mass of sulfur in the compound MgSO 4 (gram-formula mass = 120. grams per mole)? A. 20% B. 27% C. 46% D. 53%

17. Answer B is the correct answer.

18. 9. Given the balanced equation representing a reaction: 2H 2 + O 2 → 2H 2 O 2H 2 + O 2 → 2H 2 O What is the mass of H 2 O produced when 10.0 grams of H 2 reacts completely with 80.0 grams of O 2 ? What is the mass of H 2 O produced when 10.0 grams of H 2 reacts completely with 80.0 grams of O 2 ? A. 70.0 g B. 90.0 g C. 180. g D. 800. G

19. Answer B is the correct answer.

20. 10. Given two formulas representing the same compound: Formula A Formula B Formula A Formula B CH 3 C 2 H 6 CH 6 C 4 H 12 CH 3 C 2 H 6 CH 6 C 4 H 12 Which statement describes these formulas: Which statement describes these formulas: A. Formulas A and B are both empirical. B. Formulas A and B are both molecular. C. Formula A is empirical, and formula B is molecular. D. Formula A is molecular, and formula B is empirical.

21. Answer C is the correct answer.

22. 11. The sum of the atomic masses of the atoms in one molecule of C 3 H 6 Br 2 is the– A. formula mass B. isotopic mass C. percentage abundance D. percentage composition

23. Answer A is the correct answer.

24. 12. The percent composition by mass of nitrogen in NH 4 OH (gram-formula mass = 35 grams/mole) is equal to – A. 4/35 X 100 B. 14/35 X 100 C. 35/14 X 100 D. 35/4 X 100

25. Answer B is the correct answer.

26. 13. Given the balanced equation representing a reaction: 2NaCl(ℓ) →2Na(ℓ) + Cl 2 (g) 2NaCl(ℓ) →2Na(ℓ) + Cl 2 (g) A 1170. gram sample of NaCl(ℓ) completely reacts, producing 460. grams of Na(ℓ). What is the total mass of Cl 2 (g) produced? A 1170. gram sample of NaCl(ℓ) completely reacts, producing 460. grams of Na(ℓ). What is the total mass of Cl 2 (g) produced? A 355 g B 710. g C. 1420. g D. 1630. g

27. Answer B is the correct answer.

28. 14. The gram-formula mass of NO 2 is defined as the mass of – A. one mole of NO 2 B. one molecule of NO 2 C. two moles of NO D. two molecules of NO

29. Answer A is the correct answer.

30. 15. Given the balanced equation representing a reaction: CaO(s) + CO 2 (g) →CaCO 3 (s) + heat What is the total mass of CaO(s) that reacts completely with 88 grams of CO 2 (g) to produce 200. grams of CaCO 3 (s)? What is the total mass of CaO(s) that reacts completely with 88 grams of CO 2 (g) to produce 200. grams of CaCO 3 (s)? A. 56 g B. 88 g C. 112 g D. 288 g

31. Answer C is the correct answer.

32. 16. Which formula is both a molecular and an empirical formula? A) C 6 H 12 O 6 B) C 2 H 4 O 2 C) C 3 H 8 O D) C 4 H 8

33. Answer C is the correct answer.