UNIT 2: SOLUTIONS CHAPTERS 4 AND 11
Electrolytes and Non electrolytes
1. Calculate the concentration of all ions present in each of the following solutions of strong electrolytes.
a. 0.15 M Al(NO3)2
b. 0.100 mol Ca(NO3)2 in 100.0 mL of solution
c. 5.00 g NH4Cl in 500.0 mL of solution
d. 0.25 M K2Cr2O7
2. Which of the following solutions of strong electrolytes contains the largest number of ions: 100.0 mL of 0.100 M
NaOH, 50.0 mL of 0.200 M BaCl2, or 75.0 mL of 0.150 M Na3PO4?
Solubility rules and net ionics:
3. Write balanced ionic and net ionic equations for the following reactions:
a. Aqueous solutions of silver nitrate and sodium sulfate are mixed.
b. Aqueous solutions of barium chloride and zinc sulfate are mixed.
c. Aqueous ammonium carbonate + aqueous calcium chloride
d. Aqueous sodium sulfide + aqueous zinc chloride
e. Potassium phosphate (aq) + strontium nitrate (aq)
4. Write balanced net ionic equations for the reactions that occur
a. ZnS (s) and HCl (aq)
b. Na2CO3 (aq) and BaCl2 (aq)
c. Na3PO4 (aq) and HBr
d. Ba(OH)2 and HCl
e. Sr(C2H3O2)2 (aq) and NiSO4 (aq)
f.
ZnSO3 (aq) and HCl (aq)
g. Pb(NO3)2 (aq) and H2S (aq)
h. Fe(OH)3 (s) and HClO4 (s)
i.
H2SO4 (aq) and BaCl2 (aq)
j.
Zn (s) + HCl (aq)
k. K2CO3(aq) + H2SO4(aq)
l.
Ca(OH)2 (aq) + HC2H3O2 (aq)
m. Al (s) + CuCl2 (aq)
5. A lake may be polluted with Pb 2+ ions. What precipitation reaction might you use to test for the presence of
Pb 2+?
6. A sample may contain any of all of the following ions: Hg 2+, Ba 2+ , and Mn 2+. Based on the results of the
experiments listed below, which ion or ions are present in the sample solution?
- No precipitate formed when an aqueous solution of NaCl was added to the sample solution
- No precipitate formed when an aqueous solution of Na2SO4 was added to the sample solution
- A precipitate formed when the sample solution was made basic with NaOH
Solution composition
7. A solution is made by dissolving 25 g of NaCl in enough water to make 1.00 L of solution. Assume that the
density of the solution is 1.00 g/cm3. Calculate the mass percent, molarity, molality, and mole fraction of NaCl.
8. A 1.37 M solution of citric acid (H3C6H5O7) in water has a density of 1.10 g/cm3. Calculate the mass percent,
molality, and mol fraction of the citric acid.
9. Calculate the molarity, molality, and mole fraction of each of the following acids:
Acid
density
mass % of solute
a. Hydrochloric acid
1.19 g/mL
38 %
b. Sulfuric acid
1.84 g/mL
95 %
c. Acetic acid
1.05 g/mL
99 %
10. A solution is prepared by mixing 25 mL of pentane (C5H12, d= 0.63 g/mL) with 45 mL hexane (C6H14, d= 0.66
g/mL). Assuming that the volumes add on mixing, calculate the mass percent, mole fraction, molality, and
molarity of the pentane.
Solution Preparation
11. Describe how you would prepare 2.00 L of each of the following solutions.
a. 0.250 M NaOH from solid NaOH
b. 0.250 M NaOH from 1.00 M NaOH stock solution
c. 0.50 M HCl from concentrated (12 M) HCl
d. 0.50 M sodium carbonate from pure solid
12. Calculate the sodium ion concentration when 70.0 mL of 3.0 M sodium carbonate is added to 30.0 mL of 1.0 M
sodium bicarbonate.
13. A stock solution containing Mn 2+ ions was prepared by dissolving 1.584 g pure manganese metal in nitric acid
and diluting to a final volume of 1.000 L. The following solutions were then prepared by dilution:
Solution A: 50.00 mL of stock solution was diluted to 1000.0 mL
Solution B: 10.00 mL of solution A was diluted to 250.0 mL
Solution c: 10.00 mL of solution B was diluted to 500.0 mL.
Calculate the concentrations of each solution.
Solution stoichiometry
14. What mass of Na2CrO4 is required to precipitate all of the silver ions from 75.0 mL of a 0.100 M solution of
AgNO3?
15. What mass of barium sulfate can be produced when 100.0 mL of a 0.100 M solution of barium chloride is mixed
with 100.0 mL of a 0.100 M solution of iron (III) sulfate?
16. How many grams of silver chloride can be prepared by the reaction of 100.0 mL of 0.20 M silver nitrate with
100.0 mL of 0.15 M calcium chloride? Calculate the concentrations of each ion remaining in solution after
precipitation is complete.
17. A 25.00 mL sample of hydrochloric acid solution requires 24.16 mL of 0.106 M sodium hydroxide for complete
neutralization. What is the concentration of the original hydrochloric acid solution?
18. A solution is prepared by dissolving 15.0 g NaOH in 150.0 mL of 0.250 M nitric acid. Will the final concentration
be acidic, basic, or neutral? Calculate the concentrations of all the ions present in the solution after the reaction
has occurred.
Vapor pressures (Rauolt’s law)
19. A solution is prepared by mixing 50.0 g glucose (C6H12O6) with 600.0 g of water. What is the vapor pressure of
this solution at 25 °C? (At 25 °C, the vapor pressure of pure water is 23.8 torr. Glucose is a non electrolyte)
20. Pentane and hexane form an ideal solution. At 25 °C, the vapor pressure of pentane is 511 torr and hexane is
150 torr. A solution is prepared by mixing 25 mL pentane ( density= 0.63 g/mL) with 45 mL hexane (density 0.66
g/mL)
a. What is the vapor pressure of the solution?
b. What is the composition by mole fraction of pentane in the vapor that is in equilibrium with this solution?
21. Which of the following will have the lowest total vapor pressure at 25 °C?
a. Pure water (vapor pressure = 23.8 torr at 25° C)
b. A solution of glucose in water with mol fraction glucose= 0.01
c. A solution of sodium chloride in water with mol fraction NaCl= 0.01
d. A solution of methanol in water with mol fraction of methanol = 0.2
22. Henry’s law?
Colligative properties
23. A solution is prepared by dissolving 5.0 g sucrose (C12H22O11) in 175 g of water. Calculate the boiling point and
freezing point of this solution.
24. What mass of glycerin (C3H8O3) must be dissolved in 200.0 g of water to give a solution with a freezing point of
-1.50 °C?
25. A 0.350 g sample of a large biomolecule was dissolved in 15.0 g of chloroform, and the freezing point depression
was determined to be 0.240 °C. Calculate the molar mass of the biomolecule (Kf for chloroform is 4.70 °C
kg/mol)
26. Anthraquinone contains only carbon, hydrogen, and oxygen and has an empirical formula of C7H4O. the freezing
point of camphor is lowered by 22.3 °C when 1.32 g anthraquinone is dissolved in 11.4 g camphor. Determine
the molecular formula of anthraquinone.
27. If the human eye has an osmotic pressure of 8.00 atm at 25 °C, what concentration of solute particles in water
will provide an isotonic eye drop solution. (one with equal pressures)
28. Calculate the freezing point and boiling point of 0.050 m MgCl2.
29. Calculate the osmotic pressure at 25 °C of a 0.50 M solution of Ca(NO3)2 in water.
30. An aqueous solution of 10.00 g of catalase, an enzyme found in the liver, has a volume of 1.00 L at 27 °C. The
solution’s osmotic pressure at 27 °C is found to be 0.745 torr. Calculate the molar mass of the catalase.
31. Calculate the freezing point and boiling point of an antifreeze solution that is 50.0 % by mass of ethylene glycol
(HOCH2CH2OH) in water. Ethylene glycol is a nonelectrolyte.