4. Calculate the percent of the elements that are in bold in the following chemical formulas: a. Cu3P2 b. (NH4)2SO3

5. How many moles are in 3.45 g of BaF2?

6. How many atoms are in 0.432 g of Mo?

7. How many grams are in 4.32 x 1033 molecules of H2O?

8. How many moles are in 7.11 x 1012 atoms of Na?

9. Determine the empirical formulas from

a. 77.3% Ag, 7.4% P, and 15.3% O.

b.28.5% Fe, 22.9% S, and 48.6% O.

10. A compound is found to have an empirical formula of C6H8O and a molar mass of 290 g/mol. What is the molecular formula of the compound?

11. A compound was found to contain 0.1735 g of C, 0.01455 g H, and 0.2024 g N. Its molecular mass is 129 g/mol.

a. Determine the empirical formula of the compound.

b. Determine the molecular mass of the compound.

12. Balance and identify the types of the following chemical equations:

a. Li2O + Al --> Al2O3 + Li

b. Cr(OH)2 + K3N --> Cr3N2 + KOH

c. C3H4 + O2 --> CO2 + H2O

d. BaO --> Ba + O2

13. . A 45.0 mL sample of gas is at a pressure of 1.60 atm. What is the pressure, in mmHg, when the volume is 73.4 mL?

14. A sample of air at 37 oC has a volume of 486 mL. What would the volume be when the temperature is -8 oC?

15. A balloon is filled with 17.0 L of a gas at 24 oC and a pressure of 675 mmHg. What is the pressure, in mmHg, of the gas in the balloon when the temperature is 27 oC and the volume is 33.0 L?

16. A cylinder is filled with a gas at a pressure of 127.5 kPa at a temperature of 290 K. What is the temperature, in oC, when the pressure is 3.51 kPa?

17. A balloon is filled with 0.93 L of gas at a pressure of 1.15 atm and a temperature of -22oC. What is the temperature, in oC, when the volume is 0.85 L and the pressure is 1.01 atm?

18. How many grams are in 563 mL of chlorine gas at STP?

19. What volume in mL will 0.0066 mol of hydrogen gas occupy at a pressure of 0.907 atm and a temperature of 9 oC?

20. Calculate the volume of 847 g of SO2 gas at a pressure of 89.4 kPa and 40 oC.