LAB PARTNER(S) _ _ _ _ _ __
REPORT FOR EXPERIMENT 12
DATE _ _ _ _ _ _ _ _ _ __
Properties of Solutions
A.
Concentration of Saturated Solution
1. Mass of empty evaporating dish
2. Mass of dish + saturated potassium chloride solution
3. Mass of dish + dry potassium chloride, 1st heating
4. Mass of dish + dry potassium chloride, 2nd heating
5. Mass of saturated potassium chloride solution
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6. Mass of potassium chloride in the saturated solution
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7. Mass of water in the saturated potassium chloride solution
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8. Mass percent of potassium chloride in the saturated solution
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9. Grams of potassium chloride per 100 g of water (experimental)
in the original solution.
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10. Grams of potassium chloride per 100 g of water (theoretical)
(From Table 12.1) at 20°C.
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REPORT FOR EXPERIMENT 12 (continued)
B.
Relative Solubility of a Solute in Two Solvents
1. (a) Which liquid is denser, organic solvent or water?
(b) What experimental evidence supports your answer?
2. Color of iodine in water:
Color of iodine in organic solvent:
3. (a) In which of the two solvents used is iodine more soluble?
(b) Cite experimental evidence for your answer.
C.
Miscibility of Liquids
1. Which liquid pairs tested are miscible?
2. How do you classify the liquid pair organic solvent-H20, from part B, miscible or
immiscible?
D.
Rate of Dissolving Versus Particle Size
1. Time required for fine salt crystals to dissolve
2. Time required for coarse salt crystals to dissolve
3. Since the amount of salt, the volume of water, and the temperature of the systems were
identical in both test tubes, how do you explain the difference in time for dissolving the
fine vs. the coarse salt crystals?
E.
Rate of Dissolving Versus Temperature
1. Under which condition, hot or cold, did the salt dissolve faster?
2. Since the amount of salt, the volume of water, and the texture of the salt crystals were
identical in both beakers, how do you explain the difference in time for dissolving at the
hot vs. cold temperatures?
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REPORT FOR EXPERIMENT 12 (continued)
Solubility vs. Temperature; Saturated and Unsaturated Solutions
F.
Data Table: Circle the choices which best describe your observations.
NaCl
NH4 Cl
1.0 g + 5 mL water
dissolved completely? yes/no
saturated or unsaturated?
dissolved completely? yes/no
saturated or unsaturated?
1.0 g + 5 mL water + 1.4 g
dissolved completely? yes/no
saturated or unsaturated?
dissolved completely? yes/no
saturated or unsaturated?
2.4 g + 5 mL water+ heat
dissolved completely? yes/no
saturated or unsaturated?
dissolved completely? yes/no
saturated or unsaturated?
2.4 g + 5 mL water
after cooling
dissolved completely? yes/no
saturated or unsaturated?
dissolved completely? yes/no
saturated or unsaturated?
G.
Ionic Reactions in Solution
1. Write the word and formula equations representing the chemical reaction that occurred
between the calcium chloride solution, CaC1 2(aq) and the ammonium sulfate solution,
(NH4hSO 4(aq)
Word Equation:
Formula Equation:
2. (a) Which of the products is the white precipitate?
(b) What experimental evidence leads you to this conclusion?
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REPORT FOR EXPERIMENT 12 (continued)
QUESTIONS AND PROBLEMS
Use the solubility data in Table 12.1 to answer the following questions.
Show all calculations clearly. Answer with proper number of significant figures and
units. Answer all the questions in completed sentences.
1. What is the percentage by mass of NaCl in a saturated solution of sodium chloride at
50°C?
2. Calculate the solubility of potassium bromide at 23°C. Hint: Assume that the solubility
increases by an equal amount for each degree between 20°C and 30°C.
3. A saturated solution of barium chloride at 30°C contains 150.0 g water. How much additional barium chloride can be dissolved by heating this solution to 60°C?
4. A solution of KCl is saturated at 50°C.
(a) How many grams of solute are dissolved in 100.0 g of water?
(b) What is the total mass of the solution?
(c) What is the mass percent of this solution at 50°C?
(d) If the solution is heated to 100°C, how much more KCl can be dissolved in the solution without adding more water?
(e) If the solution is saturated at 100°C and t hen cooled to 30°C, how many grams of
solute will precipitate out?
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