Aleksza Honors Chemistry
Chapter 15 – Solutions Test – Version _1 (D, E, L, M, T, V)
2012-13
NAME: _______________________________________________MOD:____________
List of all those that assisted you on this test , including but not limited to: fellow students, teachers, parental units, siblings, relatives, neighbors, pets, etc.:
DIRECTIONS
 CALCULATION BASED ANSWERS: You must clearly show the logical process for solving these types of problems. Each answer must include, but is not limited to, the formula being used, units and a clearly labeled answer.
A list of “knowns” and “unknowns” is helpful.
 NON-CALCULATON BASED ANSWERS: Outlines and bullet points are acceptable. Yes, No, IDK, etc. answers alone will not be accepted. A plausible, scientific reason for the answer is required.
 If work is done on a separate page, that page must have your name on it and it be attached to this test.
 All websites, alternative text books, sources, etc. must be cited along with the problem. If you wish to list them all on one page you must identify which problem the resource is linked to. (EX: Question 1: www.chemansrsidonthave2wrk4.com/molarity )
 All work should be your own and in your own words. Work that is or appears to a copied, duplicated, etc. will receive a 0 (zero) for that problem.
 I have read these directions and understand them.
______________________________________ ___________________
Signature Date
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1. Formalin, HCHO, is used in preserving specimens. How many grams of
HCHO must be used to prepare a ___2.35____L of ____0.25____M formalin? (3 pts)
2. Why does increasing the solute concentration decrease the melting point?(3 pts)
3. What would the boiling point of a _____1.25______m BeF
2
solution be?
K b
(H
2
O) = 0.51°C/m (3 points)
4. The solubility of an ionic compound X in water at 27.5°C is 8.14 grams/liter. List all of the possible methods one might use to make more than 8.14 grams of compound X dissolve in one (1) liter of water.
(3 pts)
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5. If I dilute ____15.7____mL of _____0.5____M lithium acetate solution to a volume of ___7.2____mL what will the molarity of the resulting solution be? (3 pts)
6a. An unknown compound, Z, is observed to mix with benzene but not with water. Is the unknown compound, Z, ionic or covalent? – EXPLAIN
your answer. (3 pts)
6b. If the unknown compound, Z, is a liquid, will it be able to dissolve table salt? EXPLAIN your answer! (3pts)
7. Using chemistry concepts from this chapter explain why you are more likely to overdose on Vitamin A than on Vitamin C. (3 pts)
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8. ___10.0___g of magnesium chloride is dissolved in ___25_kg of water. a. What is the molality (m) of the solution? (2pts) b. How many moles of MgCl
2
are contained in __25____kg of solvent? (2 pts) c. How many kg of solvent would contain ___0.12___moles of
MgCl
2
? (2 pts)
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9. Given a solution of ___6__g of Sucrose (MW=342 g/mol) in ___0.5__L of water calculate the following: (25 pts total) a. The mole fraction sugar of solution (X sugar
) (2 pts) b. The mole fraction water of solution (X water
) (2 pts) c. The Molality (m) (2 pts) d. The Molarity (M) (2 pts) e. The Freezing Point Depression (K
23.76 Torr (4 pts) f
for water is 1.86) (3 pts) f. The Freezing Point of the solution (2 pts) g. The Boiling Point Elevation (Kb for water is 0.51) (3pts) h. The Boiling Point of the solution (2 pts) i. The Osmotic Pressure at ____27.5
____°C (3 pts) j. The Vapor Pressure (given pure vapor pressure of water at 25°C is
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10a. Graph the following data on a piece of graph paper or using a graphing program. (5 points)
Your graph must:

Be neat and organized (use a ruler or a graphing program) and proper report margins are to be used.

X and Y axis must have proper scale.

Have properly labeled axes with units

Use a different color or id markers for the two different solubility curves.

Have a key

Have a proper scientific tile reflecting what the graph is about.
Sodium Chloride Solubility Copper Sulfate Solubility
(
Temperature
⁰
0
C)
Solubility
(g of solute/100 mL of H
2
35.7
O)
(
Temperature
⁰
0
C)
Solubility
(g of solute/100 mL of H
2
O)
23
10 35.8
10 27.5
20
30
35.9
36
20
30
32
38
40 36.4
40 44.5
60
80
37.1
38
60
80
62
84
90 38.5
100 114
:
100 39.2
10b. Use the graph you just created to answer the following questions (5pts)
Solution A: 35.7 grams of sodium chloride dissolved in 100 mL of water at 25 ⁰ C
Solution B: 61.0 grams of or copper sulfate dissolved in 100 mL of water at 45 ⁰ C o Which solution was saturated? Which was unsaturated? Explain. o How much more solute could you add to the unsaturated solution? Explain.
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