Chemistry 6.0
Solutions
Name_________________________________
Solubility
1. Use the solubility curves above to answer the following questions:
a. Which salt is least soluble at 20°C?
b. How many grams of potassium chloride can be dissolved in 200g of water at 80°C?
c. At 40°C, how much potassium nitrate can be dissolved in 300 g of water?
d. Which salt shows the least change in solubility?
e. A solution at 30°C contains 90g of sodium nitrate in 100g of water. Is this solution
saturated, unsaturated, or supersaturated?
f. How many grams of potassium chlorate will crystallize when a saturated solution is cooled
from 80°C to 50°C?
g. How many grams of potassium chlorate are needed to saturate 10 g of water at 30°C?
h. Describe what will happen to an ammonia solution as it is slowly heated.
2
i. Describe what will happen when 80g of potassium nitrate is added to 100g of water at
40°C and stirred.
j. A solution containing 20g of ammonium chloride dissolved in 50g of water at 100°C is
slowly cooled. At what temperature will the solution begin to crystallize?
k. List 2 chemicals from the graph that would be more soluble at higher pressures.
l. List 2 chemicals from the graph whose solubility is unaffected by pressure.
2. Describe what would happen to a small crystal of the solute that is added to a solution of that
solute that is:
a. Saturated –
b. Unsaturated –
c. Supersaturated –
3. Draw the structures of each of the following and indicate if the chemical will likely be soluble or
insoluble in water:
a. CO2
b. carbon tetrachloride
c. phosphorus trichloride
3
Dilutions
4. What volume of concentrated 18 M sulfuric acid is needed to prepare 250 mL of a 6.0 M solution?
5. If 14.6 mL of water were added to 25.0 mL of a 0.100 M acetic acid solution, what molarity would
the solution become?
6. To what volume should 25 mL of 15 M nitric acid be diluted to prepare a 3.0 M solution?
7. To how much water should 50. mL of 12 M hydrochloric acid be added to produce a 4.0 M
solution?
8. Describe how to prepare 100.mL of a 0.500 M NaOH solution beginning with a 3.00M NaOH
stock solution.
9. Describe how to prepare 100.mL of a 0.500 M NaOH solution beginning with solid NaOH.
Ionic Equations
10. Write an E if the indicated substance is an electrolyte or an N if it is a non-electrolyte.
_____ HBr(aq)
_____ Na2S
_____N2O5
_____KOH
_____ CO2
4
11. Write appropriate ionization equations or dissociation equations to represent what happens when
each of the following chemicals are mixed with water:
a. HNO3(aq)
b. H2SO4(aq)
c. LiOH
d. Ba(OH)2
e. Na2SO4
12. Write molecular, ionic and net ionic equations for each of the following:
a. Solutions of potassium hydroxide and nitric acid are mixed.
b. Solutions of barium chloride and sodium sulfate are mixed.
c. Solid calcium oxide is added to a hydrochloric acid solution
d. Solutions of lithium acetate and copper(II) nitrate are mixed.
5
e. Solutions of iron(III) bromide and ammonium carbonate are mixed
f. A piece of zinc metal is added to a solution of copper(II) sulfate.
g. Solid lead(II) nitrate crystals are sprinkled into a solution of rubidium iodide.
h. A piece of aluminum metal is added to a solution of silver nitrate.
Determining ∆H From Calorimetry
Assume that the density and specific heat of all solutions are the same as water.
13. When 12.8 g of KCl dissolves in 75.0 g of water in a calorimeter, the temperature drops from
31.0°C to 21.6°C. Write the equation for this process and calculate the ΔH in kJ/mol.
6
14. Silver chloride can be precipitated by adding solid silver nitrate to a sodium chloride solution. If
0.956 g of silver nitrate is added to 21.0 mL of a 1.0 M sodium chloride solution, the temperature
increases from 25.0°C to 27.58°C.
a. Calculate the ΔH for this process.
b. Write the net ionic, thermochemical equation for this reaction.
c. Draw an energy diagram for this reaction.
d. Calculate the enthalpy change for this reaction that is required to precipitate 3.55 g of
silver chloride.
15. When 25.7 g of NaI dissolves in 80.0 g of water in a calorimeter, the temperature rises from
20.5°C to 24.4°C. Calculate the enthalpy change in kJ/mol.
7
16. When 16.9 g of NaOH reacts with 50.0 g of an HCl solution, the temperature rises from 22.4°C to
31.0°C. Assume the NaOH is the limiting reagent.
a. Calculate ΔH
b. In a separate experiment, 35.8 g of NaOH is reacted with HCl. The heat released is applied
to a block of ice at 0°C. How many grams of the ice will melt?
17. When 19.2 g of KCN dissolves in 65.0 g of water, the temperature drops from 28.1°C to 15.4°C.
Write the thermochemical equation for this process.
18. Answer the questions below using the 3 given equations:
Reaction 1:
Reaction 2:
Reaction 3:
2 Na + H2SO4  Na2SO4 + H2
Na + H2O(l)  NaOH + ½ H2
H2SO4 (l)  H2O(l) + SO3(g)
H = -577.5 kJ
H = ???
H = ???
a. Determine the enthalpy change of reaction 2, in kJ/mol, given the following experimental
data: When 1.50 g of sodium is placed in a calorimeter containing 40.0 g of water, the
temperature increases from 22.0°C to 91.0°C. (Assume the hydrogen produced in the
reaction is contained in the calorimeter and that the specific heat of the solution is the same
as it is for water).
8
b. Determine the enthalpy change of reaction 3 by using the enthalpies of formation.
c. Apply Hess’s Law to reactions 1, 2, and 3 to determine the enthalpy change for:
2NaOH + SO3  Na2SO4 + H2O(l)
d. Write the thermochemical equation for:
i. Reaction 1:
ii. Reaction 3:
e. Write the equation for reaction 2 in H notation.
f. Is reaction 2 endothermic or exothermic? Cite two reasons for your choice.
g. In reaction 3, do the reactants or the products have a lower enthalpy?
h. Draw the energy diagram for:
Reaction 1
Reaction 3
i. How many kilojoules of thermal energy are transferred when 2.09 L of hydrogen gas at
STP is produced in reaction 2?
j. How many grams of sodium would be required to react in reaction 1 if 127 kJ of thermal
energy is released?
9
Colligative Properties
H2O
Freezing
Point
(°C)
0
Boiling
Point
(°C)
100
Acetic acid
HC2H3O2
16.6
Benzene
Camphor
C6H6
C10H16O
Cyclohexane
C6H12
Solvent
Formula
Water
Kf(°C/m)
Kb(°C/m)
1.858
0.512
118.5
3.59
3.08
5.455
179.5
80.2
...
5.065
40
2.61
...
6.55
80.74
20
2.79
19. Determine the freezing and boiling points of solution consisting of 6.55 g of glucose dissolved in
21.2 g of water.
20. Determine the freezing and boiling points of a solution consisting of 1.56 g of I2 dissolved in
4.99 g of benzene.
21. How many grams of sucrose must be dissolved in 150. g of water to prepare a solution that will
boil at 100.956oC?
22. How many grams of camphor must be dissolved in 25.0 g of cyclohexane to prepare a solution
that will freeze at 6.04oC?
23. When 2.65 g of an unknown molecular solid is dissolved in 17.5 g of water, the resulting solution
freezes at −1.99oC. Determine the molar mass of the solid.
10
24. When 5.04 g of an unknown molecular solid is dissolved in 12.3 g of acetic acid, the resulting
solution boils at 120.8oC. Determine the molar mass of the solid.
25. What is the boiling point of a solution that is formed by dissolving 19.6 grams of barium
hydroxide in 115 g of water?
26. Determine the freezing point of a 14.8 % solution of aluminum chloride.
27. The soluble product that results from the reaction between 37.3 grams of lead(II) nitrate and 137
mL of 0.800 M sodium phosphate is isolated and dissolved in 2.88 x 1024 molecules of water.
What are the freezing and boiling points of this solution? Write the net ionic equation for the
reaction.
11
Acids and Bases
28. Write the name for the following acids:
a. HNO3(aq)______________________
b. HBr (aq) ______________________
c. H2CO3(aq)______________________
d. H2S(aq)
e. HNO2(aq)______________________
f. HC2H3O2(aq) ______________________
______________________
29. Write the formula for the following acids:
a. chloric acid ______________
b. hydrofluoric acid ______________
c. sulfurous acid ______________
d. carbonic acid ______________
e. hydroiodic acid ______________
f. phosphoric acid ______________
30. Acids react with metals to produce a salt and hydrogen gas. Write net ionic equations for the
following:
a.
Na
b.
HBr(aq)
HCl(aq) →
+
Ba →
+
c. Aluminum + nitric acid →
31. Acids react with bases to produce a salt and water. Write net ionic equations for the following:
a.
HClO4(aq)
+
NaOH →
b.
H3PO4(aq)
+
Ca(OH)2 →
c. Sulfuric acid + lithium hydroxide →
12
32. Write the formula for the acid and base required to produce the salt, Cs2CrO4 in a neutralization
reaction.
acid:___________________________ base:____________________________
Properties of Acids and Bases
33. Write the appropriate term that fits the description provided.
a.___________________ An ionic compound formed when an acid reacts with a base.
b.___________________ The reaction between an acid and a base.
c.___________________ A substance that conducts an electric current when in solution.
d.___________________ A proton donor.
e.___________________ A substance that has different colors in acids and bases.
f.___________________ A substance that supplies hydroxide ions in solution.
g.___________________ The removal of a hydrogen ion from an acid.
h.___________________ The ion formed when a proton is added to a water molecule.
34. Write A for acid, B for base or an X if the indicated property can apply to either.
_____ feels slippery
_____ sour taste
_____ stings in open wounds
_____ reacts with most metals
_____ phenolphthalein is colorless
_____ litmus paper turns red
_____ does not react with metals
_____ methyl orange turns orange
_____ is an electrolyte
_____ has a bitter taste
_____ can produce a salt in some reactions
_____ has a pH > 7
35. What is the conjugate acid of:
a. NO2−
b. NH3
c. HPO4−2
d. CH3NH2
36. What is the conjugate base of:
a. H2SeO3
b. HBrO4
c. HPO4−2
d. NH4+
13
37. For the following reactions, identify the acid (A), base (B), conjugate acid (CA) and conjugate
base (CB)
a. HNO2 + H2O → H3O+ + NO2−
b. HCN + H2O → CN− + H3O+
c. H2O + H2O → H3O+
+ OH−
d. H2O + F- → OH− + HF
e. NH4+ + H2O → NH3 + H3O+
f. CO3−2 + H2O → HCO3- + OH−
38. Explain the following given the equation:
NH3 + H2O → NH4+ + OH−
a. Ammonia is an Arrhenius base:
b. Ammonia is a Bronsted-Lowry base:
c. Water is a Bronsted- Lowry acid:
d. Water is not an Arrhenius acid:
14
pH
39. Determine the following quantities for a 0.00045 M HCl solution:
b. [OH−]
a. [H3O+]
c. pH
d. pOH
40. Determine the following quantities for a 0.0034 M NaOH solution:
b. [OH−]
a. [H3O+]
c. pH
d. pOH
41. Calculate pH for the following and identify if the solution is acidic, basic or neutral:
-9
b. [OH−] = 1.07 x 10−8 M
a. [H3O+] = 2.9 x 10 M
c. pOH = 12.1
42. Calculate [H3O+] for the following and identify if the solution in acidic, basic or neutral:
-3
a. [OH−] = 5.0 x 10 M
b. pH = 3.7
c. pH = 11.2
d. pOH= 6.0
15
−
43. Given the pH values determine the [OH ]. Indicate if acidic, basic or neutral.
a) 7.00
b) 11.35
c) 4.15
d) 5.09
44. Determine the pH of each solution. Indicate if acidic, basic or neutral.
a) 2.5 x 10−5 M H3O+
b) 4.0 x 10−7 M OH−
c) 3.0 x 10−3 M H+
45. Given the concentration for the following solutions, solve for the [H+] or [OH-]. Indicate if acidic,
basic or neutral.
a) 2.9 x 10−7 M H+
b) 4.6 x 10−9 M OH−
c) 8.91 x 10-4 M H+
Review
46. Which of the following will have a higher solubility?
a. Sugar and water at 50°C or at 25°C?
b. Carbon dioxide and water at 50°C or 25°C?
c. Sugar and water at 1.5 atm or 2.5 atm?
d. Carbon dioxide and water at 1.5 atm or 2.5 atm?
47. Why will sodium chloride dissolve in methyl alcohol, but not in carbon tetrachloride?
48. Why does a sugar cube dissolve more slowly than granulated sugar?
16
49. Use Lewis structures to determine if the following compounds will be more soluble in water or
carbon tetrachloride.
a. Sulfur dioxide
b. Sulfur trioxide
50. When a crystal of a solid solute is added to a solution containing that solute, the solution begins to
crystallize. What kind of solution was it before it crystallized? What kind of solution was it after
it crystallized?
51. How would you prepare the following solutions:
a. 250 mL of 0.500M HCl(aq) from a 12.0 M stock solution
b. 30.0 mL of 2.50 M NaOH from solid NaOH
52. For each of the following, write complete and balanced molecular, ionic and net ionic equations.
a. Solutions of lead(II) nitrate and potassium iodide are mixed.
b. Solutions of hydrochloric acid and silver nitrate are mixed.
c. Solutions of sodium hydroxide and iron (III) nitrate are mixed.
17
53. Which will have a higher boiling point?
a. Pure water or salt water?
b. 2m sugar solution or a 5m sugar solution?
54. Which will have a higher freezing point?
a. Pure water or salt water?
b. 2m sugar solution or a 5m sugar solution?
55. Which will have a higher vapor pressure?
a. Pure water or salt water?
b. 2m sugar solution or a 5m sugar solution?
56. Why does the vapor pressure of a solvent decrease when a solute is dissolved?
57. When does water boil at 100°C?
58. Why do certain foods have different cooking instructions for high altitudes?
59. What is the molality of a 15.66 % Na2SO4 solution?
60. What is the boiling point of the solution in the previous problem?
61. How many grams of sodium chloride are required to make 350 g of water freeze at −1.97°C.
18
62. What is the molar mass of a molecular solute that would cause 150 g of water to boil at 100.092°C
when 1.359 g of the solid is dissolved?
63. Complete and balance:
Fe(OH)3 + H2SO4(aq) →
a. How many grams of iron (III) hydroxide are required to neutralize 20.0 mL of 6.0M
sulfuric acid?
b. If 45.6 mL of a sulfuric acid solution of unknown concentration is required to titrate 20.36
g of the iron(III) hydroxide, what is the molarity of the acid?
c. Write the net ionic equation for the reaction.
64. Calculate the pH of the following and indicate if acidic, basic or neutral:
a. [H3O+] = 1.00 x 10-7 M
b. [OH−] = 8.39 x 10-2 M
c. pOH = 9.0
d. 0.071M HCl
e. 0.14 M NaOH
19
+
65. Calculate [H3O ] for each of the following and indicate if acidic, basic or neutral:
a. pH = 4.91
b. pOH = 3.62
c. [OH-] = 2.4 x 10−6 M
66. For each of the following reactions, label the acid, base, conjugate acid, and conjugate base.
a. NH3 + CH3COOH ↔ NH4+ + CH3COO−
b. HSO4− + H2O ↔ H3O+ + SO4−2
67. What is the conjugate acid of:
a. IO3−
b. HC2O4−
68. What is the conjugate base of:
a. C5H5NH+
b. HC2O4−
Cumulative Review
69. Convert 188.2 km/s to in/yr.
70. Perform each of the following calculations and report the answer in scientific notation and with
the correct significant figures.
a. 265.3 x 0.0564
__________________________
b. (36.25 − 74.1)/120
__________________________
c. 1650 + (284.8 x 0.136)
__________________________
20
3
23
71. The density of lead is known to be 11.35 g/cm . If 4.42 x 10 atoms of lead are placed into a
graduated cylinder with 26.4 mL of water, what will be the new volume of water in the cylinder?
72. Classify the following as element, compound, mixture (hetero) or solution.
Classification
air
mint chocolate chip ice cream
nitrogen gas
table salt
73. Sate the number of p+, n0, and e− in each of the following:
-2
a. 202
b. 34
80 Hg
16 S
c.
143 3+
59 Pr
74. What is the common charge on the following elements when they form ions?
a. aluminum _______
75.
c. chlorine _______
c. rubidium _______
A sample of curium-242 has a half-life of 160 days and undergoes alpha decay. Write the
nuclear equation for this process. A 0.150 gram sample of curium exists after undergoing alpha
decay for 3.95 years. What was the original sample mass of the curium-242?
76. Write the appropriate name or formula for each of the following.
Rb2C2O4
dichlorine monoxide
SiCl4
barium nitrite
CuCl2 • 2 H2O
molybdous acid
H3PO3
iron(III) nitrate nonahydrate
Mo(SO3)3
formic acid
H2Se(aq)
tin(II) hydroxide
21
77. Write nuclear equations for the following:
a. the production of bismuth-209 from an electron capture.
b. the release of a beta particle by lead-210.
78. Determine the number of water molecules in 63.52 grams of cobalt(II) nitrate hexahydrate.
79.
Determine the molecular formula for a substance that contains 52.11% C, 13.14% H, and
34.75% O and has a molar mass of 138 g/mol.
80. Write balanced equations for the following:
a. Powdered magnesium oxide is placed into water.
b. A sample of aluminum carbonate is vigorously heated in a crucible.
c. Magnesium metal is heated in the presence of iodine gas.
d. Solutions of calcium chloride and potassium carbonate are mixed
e. A sample of iron(III) hydroxide is intensely heated.
f. Hydrogen sulfide gas is bubbled through a solution of iron(III) chloride.
22
81. A titration is performed where 26.5 mL of 1.15 M sulfuric acid is used to titrate 19.4 mL of
potassium hydroxide. What is the molarity of the potassium hydroxide. Write the net
ionic equation for the reaction.
82.
Write the short-hand electron configuration, orbital filling diagram, and electron-dot
notation for the fourth period element that commonly takes on a charge of −1 as an ion.
83.
What is the wavelength of radiation that possesses an energy of 2.88 x 10−20 J/photon?
84.
Arrange the following elements in order of a) increasing ionization energy, and b)
decreasing radius. Li, O, C, K, Ne, and F
85.
Compare/contrast the properties of melting point and ease of vaporization with respect to ionic
bonds and covalent bonds.
86.
Draw a Lewis structure for aluminum sulfide.
23
87.
Draw the Lewis-dot diagrams for the iodite ion.
a. There are ___ lone pairs and ____ bonding pairs.
b. There are ____ coordinate covalent bonds?
c. What is the electron geometry? ____________________________
d. What is the molecular geometry?___________________________
e. What is the bond angle? ______________________
f. Determine the polarity
88. Draw the resonance structures for SiO3−2.
89.
Name the following hydrocarbons:
Cl
CH3 C
C
C
Cl
CH2 CH3
CH3
CH3 C
CH CH CH2 CH3
Br
90.
Find the mass of 62.5 Liters of oxygen gas at STP.
91.
What is the pressure, in kPa, exerted by 42.5 grams of xenon gas at a temperature of
75.0°C and a volume of 2.65 Liters?
24
92.
A sample of sulfur dioxide gas occupies 56.2 mL at a pressure of 772 mm and a
temperature of 95.6°C. What is the volume of the gas at STP?
93.
A 3.25 gram sample of calcium carbide, CaC2, reacts with water to produce acetylene gas
(ethyne) and aqueous calcium hydroxide. If the acetylene is collected over water at 17°C and
0.974 atm, how many mL of acetylene are produced if the yield for the reaction is 92.5%?
94.
A sample of helium effuses through a porous container 6.50 times faster than does unknown
gas X. What is the molar mass of the unknown gas?
95.
Write the equation for the dissociation of aluminum oxalate.
96.
Write the net ionic equation for the reaction between barium nitrate and potassium sulfate.
97. A solution containing 14.0 g of silver nitrate is added to a solution containing 4.83 g of calcium
chloride. Determine the mass of solid formed and the amount of excess reactant remaining.
Write the net ionic equation for the reaction.