Practice Problems Chpt. 10-13 (Bauer)

1. Calculate the amount of heat energy required to transform 7.50 g of ice (H2O (s)) O O at 0 C to steam (H2O (g)) at 100.0 C.

2. Rank the following in order of increasing melting point.

HF , MgO, H2 , HBr , KBr,

3. Give the concentrations of all ions in each of the following solutions.

(a) 0.50 M Co(NO3)2

(b) 1.0 M FeCl3

4. Calculate the number of moles of each ion present in each of the following solutions.

+ (a) Na ion in 1.00 L of a 0.251 M Na2SO4 solution.

- (b) Cl ion in 5.50 L of a 0.10 M FeCl3 solution.

- (c) NO3 ion in 100.0 mL of a 0.55 M barium nitrate solution.

+ (d) NH4 ion in 250.0 mL of a 0.350 ammonium sulfate solution.

5. What volume of 3.0 M H2SO4 can be prepared from 100.0 mL of 18.0 M H2SO4?

6. What volume of 12 M HCl must be used in order to prepare 750 mL of 0.25 M HCl?

7. When 5.0 L of water is addd to 1.0 L of 6.0 M HCl what is the concentration of the resulting solution? 8. What volume of 0.25 M Na2SO4 is needed to precipitate all of the barium, as barium sulfate, from 12.5 mL of 0.15 M Ba(NO3)2?

9. Calculate the mass of CaCO3 precipitate produced when 37.5 mL of 0.149 M Na2CO3 is mixed with 36.2 mL of 0.158 M CaCl2.

10. Molarity is defined as,

(a) grams of solute per liter of water.

(b) grams of solute per liter of solution.

(d) moles of solute per liter of solution.

2 11. What mass of K2CrO4 is needed to prepare 5.00 x 10 mL of 0.250 M K2CrO4?

12. Consider the following reaction.

PCl5 (g) ⇄ PCl3 (g) + Cl2 (g)

Suppose that 0.90 mol of PCl5 is placed in a 2.0 L container. Calculate the equilibrium concentrations of all species once equilibrium is attained assuming that K=2.0 x 10-4.

-6 13. For barium fluoride, Ksp = 1.0 x 10 . Calculate the concentration of fluoride ion in a saturated solution of barium fluoride. Calculate the solubility of barium fluoride in mol/L and in g/L.

14. In a saturated solution of zinc hydroxide the concentration of zinc ion is -9 7.2 x 10 M. Calculate Ksp for zinc hydroxide. 15. Consider the following reaction.

N2 (g) + O2 (g)  2 NO (g)

Suppose that 6.0 mol of N2 and 6.0 mol of O2 are placed in 2.00 L container. Calculate the equilibrium concentrations of all species assuming that K=2.5 x 10-3.

16. What volume of 1.00 M NaOH is required to titrate 25.0 mL of 0.154 M acetic acid?

17. Calculate the pH of each of the following solutions.

-3 (a) 1.00 x 10 M Ba(OH)2

(b) 3.50 x 10-2 M HCl

-2 18. Calculate the pH of a 1.00 x 10 M HC2H3O2 solution. For acetic acid -5 Ka = 1.8 x 10 .

19. The pH of a 0.10 M solution of a weak acid is 3.57. Calculate Ka for the acid.