Test 9 Study Guide

Calculate the molar masses and percentage composition of each of the following compounds. Show your work and always include units.

1. Ca3P2

2. Ca(OH) 2

3. Na2SO4

4. CaSO4

5. (NH4) 2SO4

Using the molar mass, convert each of the following from gramsto moles:

5. 25.0 g C7H6O2 6. 180.0 g Ca(OH)2

7. 47.2 g SO28. 48.7 g SrCO3

Using the molar mass, convert moles to grams in each of the following:

9. 11.5 moles N2O410. 10.65 moles H3PO4

1)How many grams are in 3 moles of oxygen (O)?

2)How many grams are in 3mol of diatomic oxygen gas (O2)?

3)How many grams are in 5 moles of Li2O?

4)How many moles are in 27 grams of water (H2O)?

5)How many moles are in 34 grams of NH3?

6)How many moles are in 394.7 grams of N2I6?

7)How many grams are in 0.5 moles of Ba(NO3)2?

Mole Conversions:

  1. Determine the mass in grams of each of the following:
  2. 1.35 mol Fe
  3. 24.5 mol O
  4. 0.876 mol Ca
  5. 1.25 mol Ca3(PO4)2
  6. 0.625 mol Fe(NO3)3
  7. 0.600 mol C4H10
  8. Calculate the number of moles of each compound:
  9. 21.5 g CaCO3
  10. 1.56 g NH3
  11. 16.8 g Sr(NO3)2
  12. 2.36 g O2
  13. 14.8 g N2
  14. 23.0 g H2O
  15. Calculate the number of particles in each of the following:
  16. 1.35 mol Fe
  17. 24.5 mol O
  18. 0.876 mol Ca
  19. 1.25 mol Ca3(PO4)2
  20. 0.625 mol Fe(NO3)3
  21. 0.600 mol C4H10
  22. Calculate the number of moles of each compound:
  23. 2.5 x 1024 particles CaCO3
  24. 1.56 x 1023 particles NH3
  25. 1.8 x 1025 particles Sr(NO3)2
  26. 2.36 x 1024 particles O2
  27. 1.98 x 1023 particles N2
  28. 2.0 x 1025 particles H2O
  29. Calculate the number of Liters in each of the following:
  30. 1.35 mol Fe
  31. 24.5 mol O
  32. 0.876 mol Ca
  33. 1.25 mol Ca3(PO4)2
  34. 0.625 mol Fe(NO3)3
  35. 0.600 mol C4H10
  36. Calculate the number of moles of each compound:
  37. 21.5 L CO2
  38. 1.56 L NH3
  39. 16.8 L NO2
  40. 2.36 L O2
  41. 14.8 L N2
  42. 23.0 L H2O

Which of the following pairs of compounds have the same empirical formula?

a. Acetylene, C2H2, and benzene, C6H6

b. Ethane, C2H6, and benzene, C6H6

c. Nitrogen dioxide, NO2 , and dinitrogen tetroxide, N2O4

D. Diphenyl ether, C12H8O, and phenol, C6H5OH

3. In an experiment, a 2.514-g sample of calcium was heated in a stream of pure oxygen, and was found to increase in mass by 1.004 g. Calculate the empirical formula of calcium oxide.

4. A compound has the following percentages by mass: barium, 58.8%; sulfur, 13.74%; oxygen, 27.43%. Determine the empirical formula of the compound.

5. If a 1.271-g sample of aluminum metal is heated in a chlorine gas atmosphere, the mass of aluminum chloride produced is 6.280 g. Calculate the empirical formula of the aluminum chloride.

6. If cobalt metal is mixed with excess sulfur and heated strongly, a sulfide is produced that contains 55.06% cobalt by mass. Calculate the empirical formula of the sulfide.

7. A compound has the following percentage composition by mass: copper, 33.88%; nitrogen, 14.94%; oxygen 51.18%. Determine the empirical formula of the compound.

8. A compound with the empirical formula CH2was found to have a molar mass of approximately 84 g. What is the molecular formula of the compound?

9. A compound with the empirical formula CH4O was found in a subsequent experiment to have a molar mass of approximately 192 g. What is the molecular formula of the compound?

10. A compound having an approximate molar mass of 165-170 g has the following percentage composition by mass: carbon, 42.87%; hydrogen, 3.598%; oxygen, 28.55%; nitrogen, 25.00%. Determine the empirical and molecular formulas of the compound.

11. A compound consists of 65.45% C, 5.492% H, and 29.06% O on a mass basis and has a molar mass of approximately 110 g/mol. Determine the molecular formula of the compound.