1. Moles & Stoichiometry Whiteboard Review

2. What is the gram-formula mass of (NH4)3PO4?

3. 149.0 g/mol

4. What is the gram-formula mass of Ca3(PO4)2 ?

5. 310.0 g/mol

6. What is the mass of 1 mol of Li?

7. 6.9 g/mol

8. What is the total mass of 2.0 moles of H2 (g)?

9. 4.0 g

10. How many moles are in 39 grams of LiF?

11. 1.5 moles

12. What is the percent composition by mass of nitrogen in (NH4)2CO3?

13. 29.2%

14. Which of the following compounds has the smallest percent composition by mass of chlorine?
a) HCl
b) KCl
c) LiCl
d) NaCl

15. KCl

16. What is the molecular formula of a compound that has a molecular mass of 92 and an empirical formula of NO2?

17. N2O4

18. Vitamin C has an empirical formula of C3H4O3 and a molecular mass of 176. What is the molecular formula of Vitamin C?

19. C6H8O6

20. Given the balanced equation representing a reaction:
F2(g) + H2(g) 2HF(g)
What is the mole ratio of H2(g) to HF(g) in this reaction?

21. 1:2

22. Given the balanced equation:
2C + 3H2  C2H6
What is the total number of moles of C that must completely react to produce 2.0 moles of C2H6?

23. 4.0 mol

24. Given the reaction:
6 CO2 + 6H2O  C6H12O6 + 6O2
What is the total number of moles of water needed to make 2.5 moles of C6H12O6?

25. 15 mol

26. Given the compound C4H10O8,
a) Calculate the molar mass of the compound.
b) Calculate the number of moles in 17.7 grams of the compound.
c) What is the empirical formula for this compound?

27. a) 186 grams b) .095 moles c) C2H5O4

28. Gypsum is a mineral that is used in the construction industry to make drywall (sheetrock). The chemical formula for this hydrated compound is CaSO4・2H2O.
Calculate the gram formula mass of gypsum.

29. 172.2 g/mol

30. Gypsum is a mineral that is used in the construction industry to make drywall (sheetrock). The chemical formula for this hydrated compound is CaSO4・2H2O.
Calculate the percent composition by mass of water in gypsum.

31. 20.9%

32. Given the reaction:
N2 + 3 H2   2 NH3
How many grams of ammonia are produced when 1.0 mole of nitrogen reacts?

33. 34 grams

34. A student obtained the following data to determine the percent by mass of water in a hydrate. What is the approximate percent by mass of the water in the hydrated salt?

35. 12%

36. Balance the equation below, using the smallest whole-number coefficients.
____ Al (s) + ____ CuSO4 (aq)  ____ Al2(SO4)3 (aq) + ____ Cu (s)

37. 2 Al (s) + 3 CuSO4 (aq)  Al2(SO4)3 (aq) + 3 Cu (s)

38. Name the following compound: CuSO4

39. copper (II) sulfate

40. How many grams of Al2(SO4)3 does this represent?
2 Al (s) + 3 CuSO4 (aq)  Al2(SO4)3 (aq) + 3 Cu (s)
According to the balanced equation above, if 1.6 moles of CuSO4 react completely, how many moles of Al2(SO4)3 will be produced?
How many grams of Al2(SO4)3 does this represent?

41. 0.5 moles
171.0 g