Download Semester 2 Review

Chemistry 2nd Semester Study Guide
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Name: ___________________________
This is the majority of terms and topics that will be included on the semester test.
You will be given a periodic table and formula sheet.
You may use a calculator.
UNIT 7 – THE MOLE
1. What is a mole?
 1 mole = ______________________ atoms Fe
 1 mole = ______________________ molecules of H2O
 1 mole = ______________________ formula units of NaCl
 1 mole = ______________________ liters of gas at STP
 1 mole = ______________________ g Al
 1 mole = ______________________ g Al2(SO4)3
2. 1 mole Fe = _______________ atoms = _____________ grams
3. Calculate the number of moles of a gold sample containing 3.33x10 24 atoms.
4. Calculate the grams of 1.25 moles of magnesium.
5. Calculate the grams of 1.34x 1025 atoms of Lead.
6. Determine the molar mass of ammonium dichromate (NH4)2Cr2O7.
7. Circle the empirical formulas, square the molecular formulas. Explain how they are different.
C3H6O3,
CH2O,
C6H12O6
8. Determine the empirical formula for a compound made up of 80.68% mercury, 12.87% oxygen,
and 6.45% sulfur.
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9. Caffeine is a compound that was found to have the empirical formula C4H5N2O. If it’s molar
mass is 194.19 g/mol, calculate its molecular formula.
10. If the molecular compound of glucose is C6H12O6, what is the empirical formula?___________
What would you need to know to switch from the empirical formula to the molecular? __________
11. Calculate the percent composition of Lead (II) chloride PbCl2.
UNIT 8 - STOICHIOMETRY
12. The reactant that runs out first and limits the amount of product formed is called the
_____________ _____________. The left over reactant is called the ____________ ___________.
13. How do you determine actual yield? (Experiment / Calculation) How do you determine
theoretical yield? (Experiment / Calculation) Which is generally greater? (Actual / Theoretical)
14. The experimental trial for a reaction produced 13.1 grams of CaO. The stoichiometric calculation
showed that 13.9 should form. What is the actual yield? _________ Theoretical yield? _______
Percent yield? __________
15. How many grams of ammonia can be produced if 12.0 mol of nitrogen are reacted with
excess hydrogen according to the equation: N2 + 3 H2 ---> 2 NH3?
16. In the reaction, 2 K + Cl2  2 KCl, if you have 4 moles of potassium and 3 moles of chlorine,
which is the limiting reagent? ___________ How many moles of product could form from this
limiting reactant? _____________
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17. In the following reaction: 2KClO3  2KCl + 3O2, how many grams of potassium chlorate
(KClO3) must be decomposed to yield 30.0 grams of oxygen?
18. According to the reaction: Zn + H2SO4  ZnSO4 + H2, if 20.5 moles of zinc react with excess
sulfuric acid, how many formula units of zinc sulfate will be produced?
19. For the reaction: NaCl + AgNO3  NaNO3 + AgCl, if 10.0 grams of sodium chloride and 15.0 g
silver nitrate react, identify the limiting and excess reactants. How many grams of silver chloride
are produced?
20. What is the percent yield if 9.05 g of zinc react with excess hydrochloric acid to produce 0.259 g
hydrogen gas according to the following equation: 2 HCl (aq) + Zn (s)  ZnCl2 (aq) + H2 (g)
UNIT 9 – GAS LAWS
21. a. 24˚C = ______________ Kelvin
b. 392 K = ____________ Celsius
22. Standard pressure = _________ atm = ____________ kPa
Standard temperature = ____________K = ________________ degrees Celsius.
23. 1 mole of any gas (CH4, CO2, H2, etc…) = ______________ L (if at STP)
24. At an amusement park, a balloon is filled with 5.00 L of helium at a temperature of 308 K. What
will be the volume of the balloon when it is brought into an air-conditioned house at 295 K?
25. Your friend sits on a 25.0 L ball, decreasing the volume to 17.5 L. What is the new pressure
inside the ball if the original pressure in the ball is 100.3 kPa?
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26. 150 mL of oxygen has a pressure of 752 mm Hg at 22˚C. Calculate its volume at STP.
27. When the amount of gas in a rigid container increases, the pressure _________________
because…
28. When the temperature of a gas increases, its volume will _____________ if the container is
flexible because…
29. When you increase the volume on a sample of gas, the pressure will ______________
because…
30. If the temperature increases, the pressure will ______________ because…
31. What are the four variables that describe a gaseous system?
1.
2.
3.
4.
32. Temperature must be in ________________ when calculating gas law problems.
33. How many moles of a gas will occupy 2.50 L at 25.6 degrees Celsius and 1.95 atm?
34. Use the reaction shown to calculate the mass of iron that must be used to obtain 0.500L of
hydrogen at 24.3 degrees Celsius and 0.950 atm of pressure. 3Fe + 4H2O  Fe3O4 + 4H2
35. Calculate the volume that 3.60 grams of H2 gas will occupy at 295 K and 125.0 kPa?
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UNIT 10 - SOLUTIONS
36. What unit do chemists use to describe concentration? ________________
37. Calculate the molarity for each of the following solutions:
a. 3.4 moles of NaCl dissolved in 0.956 L of solution
b. 1.28 g of CuSO4 dissolved in 150 mL of solution
38. How many mL of 2.0 M KOH stock solution do you need to prepare 100 mL of 0.40 M KOH?
39. How would you prepare 500 mL of 1.5 M NaCl? How many grams of NaCl would you need?
What would you do with it?
40. In general, the solubility of most solid substances ________________ as temperature increases.
The solubility of gases, however, ____________________ as temperature increases. Pressure
only changes the solubility of __________________.
41. List the factors that affect how fast a substance dissolves.
1)
2)
3)
42. Describe the following types of solutions:
Saturated:
Unsaturated:
Supersaturated:
43. Describe a solute and solvent.
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44. Circle the chemicals that are soluble in water. Cross out the ones that are not. Explain each!
Fe (iron)
MgCl2
C5H10
SiO2
45. Which of the following compounds would conduct electricity when dissolved in water? (Circle)
Br2 (bromine liquid)
C4H10 (lighter fluid)
CaCl2 (ionic)
Al (Aluminum)
46. A 0.600 L sample of a 2.50 M solution of KI contains what mass of KI?
47. Calculate the molarity of a 0.205 L solution that contains 63.8 grams of NaCl.
48. What is the volume of a 0.1250 M solution of AgNO3 that contains 1.75 moles of solute?
UNIT 11 – REACTION RATES
49. List the factors that affect the RATE of a chemical reaction. Tell HOW they affect the rate.
1)
2)
3)
4)
5)
50. What is a catalyst? How is an enzyme like a catalyst? How do catalysts work?
51. In order for a reaction to occur, the reactants must ___________________ with enough
_____________________ and the correct ___________________________. This will create an
_________________________ ___________________, which can form product.
52. The amount of energy needed for an effective collision is called the _______________________
_____________________.
53. What happens to the rate of a non-equilibrium chemical reaction over time? Why?
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54. Reaction rate could be measured as disappearance of ____________________ or formation of
___________________ per unit time.
UNIT 12 - EQUILIBRIUM
55. Dissociation is the process of breaking apart into ions. This is the equation for the dissociation of
mercury (II) chloride: HgCl2 (s)  Hg2+ (aq) + 2 Cl- (aq). Write the Ksp expression for this
reaction. What does a very small Ksp mean (like 0.000025)?
56. A double arrow signifies a ___________________ reaction, while a single arrow signifies a
_______________________ reaction.
57. A reaction can go to completion because of the evolution of a _____________________ or the
formation of a __________________________.
58. ____________________ ____________________ explains how an equilibrium system will
respond to stress.
59. Choose shift right, left, or no shift.
C (s) + H2O (l) + heat  CO (g) + H2 (g)
a. Cooling
____________________________
b. Adding water
____________________________
c. Increasing the pressure
____________________________
d. Removing H2 as its formed
____________________________
e. Adding CaCO3
____________________________
60. Describe chemical equilibrium.
61. Write the equilibrium expression for: 4HCl (g) + O2(g)  2Cl2(g) + 2H2O (g)
What does an equilibrium expression (Keq) describe?
62. If you calculate a large number for the constant expression above, what does that tell you?
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63. For the reaction: Heat + H2(g) + I2(g)   2HI(g)
A. How will an increase in temperature change the concentration of hydrogen gas? ________
B. How will an increase in pressure affect the system? ___________________
C. Which direction will the addition of iodine gas shift the system? _________________
What does this do to the concentration of hydrogen gas? _______________________
64. At 773 K, the reaction: 2 NO(g) + O2 (g)  2NO2 (g) produces the following concentrations:
[NO] = 0.00349 M; [O2] = 0.80 M; [NO2] = 0.250M. What is the equilibrium constant expression
for the reaction, and what is the equilibrium constant for the reaction? What is favored at
equilibrium?
UNIT 13 – ACIDS & BASES
65. List 5 properties of an acid and 5 properties of a base.
1)
1)
2)
2)
3)
3)
4)
4)
5)
5)
66. __________________ acids and bases ionize completely, while____________________ acids
and bases only slightly ionize.
67. Circle the strong base and put a box around the strong acid.
HCl
NH3
CH3COOH
NaOH
68. What is an amphoteric substance?
69. Complete the following table:
pOH
pH
6.35
[H3O+]
[OH-]
Acid or Base?
2.34 x 10-3
6.57 x 10-9
70. If the concentration of nitric acid, a strong acid, is 0.00025 M, calculate the pH and pOH.
71. What is the [H+] concentration of a solution with a pH of 2.687? What is the [OH-] concentration?
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72. Describe the differences between an Arrhenius and a Bronsted-Lowry acid and base.
73. Identify the Bronsted-Lowry acid-base pairs in each of the following reactions by labeling each
substance with A, B, CA, and CB.
a. NH3 + H2O  NH4+ + OHb. HC2H3O2 + H2O  C2H3O2- + H3O+
74. What are the formulas for hydroxide __________ and hydronium _____________?
75. An acid + a base yields a _________ + _________. This is a ____________________ reaction.
76. The process used to find the concentration of an acid or a base is a ___________________.
77. If 25.0 mL of 0.20 KOH were used to titrate 15.0 mL of HCl, what is the molarity of the acid?
______KOH + _______HCl 
- Which substance is the titration standard? ____________________
- What must be added to signal the end of the titration? ____________________
- When the moles of acid = moles of base, what has been reached? _____________________
- What is the pH of this solution at the end of the titration? ______
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*** You will be provided with the following equations on the semester test:
% yield 
actual
 100%
theoretical
V
T
P1V1 = P2V2
V P V P
T
T
1
1
1
2
1
1
V2
T
2
P P
T T
2
2
1
2
1
2
1 atm = 101.3 kPa
PV = nRT
R = 0.0821 Latm/Kmol
M= mol of solute
L of solution
aA + bB  cC + dD
10
K
eq

[C ]c [ D] d
[ A] a [ B]b
pH = -log[H+]
10-pOH = [OH-]
pOH = -log[OH-]
pH + pOH = 14
10-pH = [H+]
[H+][OH-] = 1 x 10-14