Download CHH Review Unit 12 with answers

Name: __________________________________ Date: ___________________
Period: _____
Review Chemistry I Honors Unit 12: Solutions and Equilibrium
1. A solution consists of a _solute___ dissolved in a ___solvent__.
2. A solution is a ___homogeneous____ mixture. (which means _same_ throughout)
Is this type of mixture a pure substance, a compound, both, or neither? (circle one)
3. Classify the following materials as: solution (S) or heterogeneous mixture (M)
__S__ a. smoky air
__S__ g. salt water (NaCl + H2O)
___S_ b. sugar water (C12H22O11 + H2O)
__S__ h. milk
___S_ c. vinegar (HC2H3O2 + H2O)
__M__ i. soda with bubbles
__S__ d. Gatorade
__S__ j. oil-based paint
__X__ e. pure iodine (I2)
__S__ k. fog
___X_ f. pure distilled water (H2O)
__S__ l. ethanol in water (C2H5OH + H2O)
4. There is a relatively large amount of solute dissolved in a concentrated / dilute solution. (circle one)
There is much more ___solute___ than solvent_____ in a dilute solution.
5. Molarity is the ratio of _moles_ of __solute__ per _liter_ of _solvent_.
A 3.0 molar solution (3.0 M) has _____ mole(s) of solute in every _____ liter(s) of solution.
6. To dilute a solution, you can add more ___solvent__ which will change the molarity of the
solution, but will not change the number of __moles__ of solute.
7. A(n) __electrolyte__ is an ionic (or very polar) compound that forms __ions in
solution and will conduct electricity.
Nonpolar covalent compounds (like H2O , C8H18 , CCl4 , C2H5OH) are typically _nonconductive__.
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8. Complete the phrase that describes the types of substances that will generally dissolve in each other:
like dissolves _like.
Therefore, polar solvents (like water) can dissolve _polar or ionic solutes (like alcohols, sugars,
ionic compounds, etc.).
But nonpolar solutes (like fats, oils, hydrocarbons, etc.) will dissolve in nonpolar solvents.
9. A solution is formed by adding methanol, CH3OH, to water. Identify each of the following
intermolecular attractions as breaking or forming in the solution process: (circle answers)
breaking / forming
methanol – methanol
breaking / forming
water – water
breaking / forming
methanol – water
10. In general, the stronger the intermolecular attractions between solute and solvent molecules,
the ___greater__ the solubility.
11. In general, the __weaker__ the intermolecular attractions between solute and solute molecules,
the lower the solubility.
12. A tincture of iodine can be used as a disinfectant. This solution is can be made by mixing:
2 g of solid iodine (I2)
3 g of sodium iodide (NaI)
55 g of liquid ethanol (C2H5OH)
40 g of water (H2O)
The solvent in this mixture is best identified as ___ because C has more volume or mass__.
A.
B.
C.
D.
I2
NaI
C2H5OH
H2O
13. Three factors that typically cause a solid to dissolve faster in a liquid are:
increase / decrease __temperatures_________________________
increase / decrease _solvent____
increase / decrease ____concentration_______________________
14. Gases dissolve faster in liquids at _lower__ temperatures and at higher _pressures__.
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15. Label each solution as saturated, unsaturated, or supersaturated based on the addition of solute:
unsaturated___
__supersaturated_
__saturated
16. A solution that contains less solute than can be dissolved at that temperature is __unsaturated_.
17. If solute crystals are added to a saturated solution, the crystals will…
________fall to the bottom undisolved______________________________________.
18. If the addition of a seed crystal causes dissolved solute to crystallize, the original solution was
_supersaturated___.
For # 19-23, consider the graph of solubility curves below.
19. Which substance has the lowest solubility at 20oC?
__KClO3________
20. If 40 g of KCl is dissolved in 100 g of water
at 80oC, then the solution is __unsaturated___.
21. If 80 g of KNO3 is dissolved in 100 g of water
at 40oC, then the solution is _supersaturated__.
22. If 80 g of KNO3 is dissolved in 100 g of water
at 50oC, then the solution is _saturated_.
23. How many grams of NH4Cl can dissolve in 100 g
of water at 70oC? 60 g
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24. When a reaction has reached equilibrium, which one of the following could NEVER be true?
A. there are more products than reactants
B. there are more reactants than products
C. there are no reactants left
D. the reactants are still changing into products
E. the products are changing back into reactants
25. When a reaction has reached equilibrium, which of the following is TRUE?
A. the reaction stops
B. the forward reaction continues
C. the reverse reaction continues
D. BOTH the forward and reverse reactions continue
26. A chemical reaction in is dynamic equilibrium when the relative forward and reverse rates of the
reaction are _constant_, and the total amounts of reactant and product are __constant__.
R(g)
⇄
P(g)
At time A, the concentrations of R and P are:
constant / equal / zero .
At time B, the forward rate of reaction is:
greater than / equal to / less than
the reverse rate of the reaction.
concentration (M)
27. Two gases were placed in a container and allowed to reach equilibrium shown in the equation above.
The diagram below shows how the concentrations of gases R and P in this system changed over time.
At time C, concentrations of R and P are:
constant / equal / zero .
[R]
[P]
A
B
time (s)
C
28. Circle the letter of each sentence that is TRUE about
the saturated solution pictured here:
A. The total amount of dissolved solute remains constant.
B. The total mass of undissolved crystals remains constant.
C. When the rate of solvation equals the rate of crystallization,
a state of dynamic equilibrium exists.
D. If more solute were added to the container,
the total amount of dissolved solute would increase.
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For #29-34, you may use the following formulas:
M=
mol
L
M 1 V 1 = M 2V 2
29. What is the molarity of a solution that contains 9.50 moles of solute in 3.00 L of solution?
(Ans: 3.17 M)
30. What is the molarity of a solution containing 116 g NaCl of solute in 775 mL of solution?
(Ans: 2.55 M)
31. How many moles of solute are in 3.20 L of a 1.50 M solution of sodium chloride?
(Ans. 4.80 mol)
32. How many moles of solute are in 40.0 mL of a 0.615 M solution?
(0.0246 mol)
33. How many liters of a 0.510 M solution are contain 0.242 moles of solute?
(Ans: 0.475 L)
34. What mass of glucose (C6H12O6, 180.18 g/mol) is needed to make 5.00 mL of a 0.200 M solution?
(Ans: 0.180 g)
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For #35-38, you may use the following formulas:
M=
mol
L
M 1 V 1 = M 2V 2
35. How many mL of a 0.150 M NaBr solution are needed to make 100 mL of 0.0500 M NaBr?
(Ans: 33.3 mL)
36. If 20.0 mL of 12.1 M HCl is used to make a 5.00 L aqueous solution, what is the molarity of the dilute
solution? (hint: choose mL or L, not both)
(Ans: 0.0484 M )
Cu(s) + 2 AgNO3(aq)  Cu(NO3)2(aq) + 2 Ag(s)
37. Solid copper is added to an aqueous solution of silver nitrate shown in the reaction above.
What volume of 1.65 M AgNO3(aq) solution is needed to react completely with 0.250 moles of Cu(s) ?
(Ans: 0.303 L or 30.3 mL)
2 Al(s) + 3 ZnCl2(aq)  2 AlCl3(aq) + 3 Zn(s)
38. Solid aluminum is added to an aqueous solution of zinc chloride shown in the reaction above.
What volume of 1.20 M ZnCl2(aq) solution is needed to react completely with 9.44 grams of Al(s) ?
(Ans: 0.437 L or 43.7 mL)
2 KI(aq) + Pb(NO3)2(aq)  2 KNO3(aq) + PbI2(s)
39. Aqueous solutions of potassium iodide and lead(II) nitrate are mixed to produce solid lead(II) iodide
precipitate shown in the reaction above. If 12.7 mL of 0.425 M KI(aq) solution is added to an
excess of Pb(NO3)2(aq) , what is the maximum mass of PbI2(s) precipitate that could be recovered?
( molar mass of PbI2 = 461.00 g/mol )
(Ans: 1.24 g)
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