2010-2011 Study Guide for 4th Quarter Final along with a few questions on moles,
stoichiometry, and thermochemistry (Taken on Semester Final Day)…..and DuPage County
Common Chemistry Assessment (Taken on June 3, 2011)
REACTION RATES:
1. List the 4 factors that affect the rate of reactions. (i.e…..temperature is one…)
1. Nature of reactants (complexity of bonds)
2. Temperature
3. Concentration
4. Surface Area (size)
5. Catalysts
2. Define the following terms:





Activation energy pg. 736 energy required to achieve the tranition state and form the
activated complex
Activated complex pg. 736 transitional structure; is neither reactant nor product but
has partial characteristics of both
Catalyst pg. 743 substance that increases the rate of the reaction without itself being
used up
Exothermic reaction process that releases heat
Endothermic reaction process that absorbs heat
3. Know how to interpret a potential energy diagram.
Z
Q+R
X+Y
What do the following letters represent?
 X + Y reactants (forward rxn)
 Q + R products (forward rxn)
 Z activated complex
 a PE of reactants
 e PE of products
 c PE of activated complex
 b activation energy of forward rxn
 d heat of reaction ΔH
4. This potential energy diagram represents an ( exothermic , endothermic ) reaction.
5. On the potential energy diagram above, illustrate using a colored pen or pencil, how the
addition of a catalyst would affect this reaction.
WATER
6. Draw a water molecule and label the polarity of the oxygen and the hydrogen atoms.

Water is a ( polar, nonpolar ) molecule.
7. What type of bonding do you find between the hydrogen of one water molecule and the
oxygen of another molecule? Hydrogen Bonding
8. Why does water have a higher boiling point than most other substances of similar molar
mass? Hydrogen Bonding
9. Why does water have a high surface tension? Hydrogen Bonding
10. Why is ice less dense than water? (What happens to the water molecules when water
freezes?) Ice has a more open structure because the hydrogen bonds keep other water
molecues from getting inside the hexagonal ring structure. Thus there are fewer molecules
packed in a given volume, giving ice its lower density. Pg. 470
Solutions
11. What does “like dissolves like” means? Polar molecules (solutes) dissolve in polar solvents
12. Oil and water are immiscible…they do not mix. Why is this so? Oil is NONPOLAR and water
is POLAR
13. Define the following terms:
 Solvent pg. 502 substance that does the dissolving (larger amount)
 Solute pg. 502 substance that is dissolved (smaller amount)
 Solution pg. 501 homogeneous mixture of 2 or more substances in a single physical
state
 Aqueous solution pg. 5050 solution in which WATER is the SOLVEN




Electrolyte pg. 505 substance which conducts electricity-ionic solids are electrolytes
but either need to bin in solution or in molten state
Unsaturated solution pg. 511 solution that contains LESS dissolved solution that it can
hold at given conditions
Saturated solution pg. 511 solution that contains as much dissolved solute that it can
hold at given conditions
Supersaturated solution pg. 511 solution that contains more dissolved solute than a
saturated; excess solute will precipate out leaving a crystallized solid
14. A student dissolves 5.00 g of NaCl in 200 mL of water. This student places a conductivity
apparatus into the solution. The light bulb lights.
 What type of solution did this student make? Aqueous solution (water is the solvent)
 What is the solute? NaCl What is the solvent? H2O
 If a solute conducts electricity when dissolved in water, it is an electrolyte
 In general, acids, bases, and ionic compounds conduct electricity.
 What is the molarity of this solution? (Show your calculation!)
M= moles
L

Why does NaCl conduct electricity when it is dissolved in water?
Pg. 505 A substance that dissolves in water to form a solution that conducts an electric
current is called an electrolyte. Sodium Choloride is an an electrolyte because it
dissolves in water to form Na+ and Cl- ions.
 What factors would increase the rate at which the
sodium chloride would dissolve?
1. Increase temperature of solvent
2. Smaller pieceslarge surface area of NaCl (grind NaCl
into small pieces)
3. Stir Solution
 What factors would decrease the rate at which the
sodium chloride would dissolve?
1. lower temperature of solven
2. use bigger pieces of NaCl (small surface area)
3. Do not stri
15. Know how to interpret solubility curves.



How many grams of KNO3 will dissolve in 100 g of water at 50⁰C? 80 grams
What is the maximum amount of NH4Cl that can dissolve in 50 g of water at 90⁰C? 70
grams
If at point A all solute is dissolved, this solution would be ( unsaturated, saturated,
supersaturated ).
NH3 is a gas. What general statement can you make about the solubility of gases
compared to most solids?
For gases, as temperature increases, solubility decreases.
16. Colligative properties can only be applied to solutions. By definition, one of the properties
of a solution is a colligative property if it depends only on the number of particles of solute and
not the identity of the solute.
17. Boiling point and freezing point are two colligative properties of solutions. When a solute is
added to a solvent, such as water, the boiling point ( increases, decreases ).
18. When making ice cream, salt is added to ice. That is because the salt (solute) causes the
freezing point of water to ( increase, decrease ). Thus, freezing point depression is a
colligative property of a salt/water solution.
More molarity practice:
19. A 6.50 M solution of KNO3 contains 13.00 moles dissolved in 2 liters of solution.
6.5M = 13.00 moles KNO3
X
20. In 2.00 liters of a 0.25 M KCl solution, how many grams of KCl are there?
0.25 M = X moles KCl
2.00 L
0.5 moles KCl = (39.0983 + 35.453) g
1 mole KCl
37.2 grams KCl
ACIDS AND BASES:
21. What is the definition of an Arrhenius acid? A substance that dissociates in water to
produce HYDROGEN IONS (H+) pg. 599 in text
22. What is the definition of an Arrhenius base? A substance that dissociates in water to
produce HYDROXIDE IONS (OH-) pg. 599 in text
23. On the line before each compound, indicate if that compound is an acid or a base, according
to Arrhenius definition. On the line following the compound, write the correct name of the acid
or base.
A HCl
Hydrochloric Acid
B Ca(OH)2 Calcium Hydroxide
B NaOH Sodium Hydroxide
A H2SO4 Sulfuric Acid
A HBr Hydrobromic Acid
A Fe(OH)3 Iron (III) Hydroxide
A HNO2 Nitrous Acid
A H3PO4 Phosphoric Acid
24. On the line in front of each characteristic, indicate if the characteristic helps define an acid,
a base, or both, or neither.
B turns red litmus blue
A reacts with metals
A turns blue litmus red
Both is an electrolyte
B feels slippery
A tastes sour
B has a pH greater than 7
A has a pH less than 7
N has a pH equal to 7
B tastes bitter
A produces H+ ions
B produces OH- ions
What is the relationship between the concentration of H+ ions and the concentration of OH—
ions in an acid? H+ > OH- In a base? OH- > H+
pH
25. pH is the measure of H+ Hydrogen/ H3O+ Hydronium ion concentration.
26. In an acid the concentration of H+ ions is greater than the concentration of OH- ions.
27. Again…..a pH in the range of 0—6.9999 is an Acid
28. A pH in the range of 7.00+--14 is a Base
29. A pH equal to 7.00 is Neutral
30. As the pH value increases, the H+ ion concentration ( increases, decreases ).
1.00 x 10-14 = [H3O+][OH-]
30. Find H3O+ concentration if OH- concentration is:
4.26 x 10-11
7.26 x 10—10
31. Find the OH- concentration if H3O+ concentration is:
3.72 x 10-8
3.4 x 10-2
pH = –log[H3O+] or pH = –log[H+]
32. Find the pH of the following hydronium ion (H3O+) concentrations
1.00 x 10-3
-log(1.00 X 10 -3) = 3
1.00 x 10-5 -log(1.00 X 10 -5) = 5
1.00 x 10-7
-log(1.00 X 10 -7) = 7
What’s the pattern? The pH = the power IF
the number is one
3.25 x 10-12
-log(3.25 X 10 -12) = 11.49
6.62 x 10-4 -log(6.62 X 10 -4) = 3.18
14 = pH + pOH
33. Find the following:




What is the pOH if the pH is 6.5? pOH=14.-6.5=7.5
What is the pH if the pOH is 11.2? pH=14-11.2=2.8
What is the pH if the pOH is 8.43? pH +pOH = 14 pH + 8.43 = 14
What is the pOH if the pH is 1.00? 13=pOH
pH=5.57
Titrations
During your titration lab, a know molarity and quanity of an acid (Day one) was titrated with a
unknown molarity of the a base.
34. The reaction between an acid and a base is known as a neutralization reaction.
Such a reaction yields a water and salt
35. An example of a neutralization reaction is:
HCl + NaOH  NaCl + H2O
Notice that in a neutralization reaction between and Arrhenius acid and an Arrhenius base, the
products are always a water and salt
36. The point where there is a sudden change in color indications that neutralization has
occurred is called the endpoint.
37. In order for you to know when you reach the end point, an acid-base indicator is placed in
the flask.
38. The indicator you used in your lab is called phenolpthalein This indicator is colorless in an
acid, but turns pink in a base.
39. When neutralization occurs, the number of hydrogen H + ions equals the number of
Hydroxide OH - ions.
40. By carrying out a titration, one can calculate the molarity of an unknown acid or base given
three variables for the following equation:
MaVa = MbVb
NOTE: This equation only works when there is a one/one ratio of acid to base in the balanced
chemical equation. Since the only problems you will be given to solve involve a one to one mole
ratio of acid to base, you have no worries!
Solve the following:
If 4.7 mL of NaOH is used to neutralize 10.0 mL of 0.100 M HCl, what is the molarity of the
base?
Ma =0.100 M
MaVa = MbVb
Va= 10.0 mL
(0.100M) (10.0mL) = Mb (4.7mL)
Mb= ?
.1 X 10 = 0.21 M = Mb
Vb= 4.7 mL
4.7
If 44 mL of 0.200 M NaOH is used to neutralize 10.00 ml of acetic acid, what is the molarity of
the acid?
MaVa = MbVb
Ma (10.0mL) = 0.200M(44mL)
.2 X 44 = 0.88 M = Ma
10
How many milliliters of a 0.200 M solution of NaOH will be needed to neutralize 20.00 mL of a
0.120 M solution of HCl?
MaVa = MbVb
(0.120M) (20.0mL) = 0.200M(Vb)
.12 X 420 = 0.12 mL = Vb
.2
GAS LAWS
41. Convert 0.600 atm to mm Hg.
.600 atm X 760 mmHg =456 mmHg
1 atm
42. Convert 2.50 atm to kPa.
2.50 atm X 101.325 kPa =253 kPa
1 atm
43. The volume of a sample of gas has increased (at constant temperature), therefore, the
pressure on the sample of gas must have deceased. (Pressure ↑ Volume↓, inverse
relationship)
44. Pressure and volume changes at a constant temperature can be calculated using the
following formula:
P1V1=P2V2
45. If the pressure on a 425-mL sample of gas is decreased from 855 mmHg to 759 mmHg.
What will the new volume of the gas be (at constant temperature)? P1V1 = P2V2
855 mmHg (425 mL) = 759 mmHg (V2)
V2 = 479 mL (Also, answer checks out conceptually. Pressure goes down, volume goes up,
inverse relationship)
46. What is meant by the absolute zero of temperature? Absolute zero is the temperature at
which all molecular motion stops. It is 0 K or -273 C. The Kelvin scale is based on absolute
zero.
47. What is the mathematical formula that is used to convert ˚C to Kelvin? C + 273 = K
48. The volume of a sample of gas has decreased (at constant pressure); therefore, the
temperature of the sample of gas must have __decreased (direct relationship between V &
T)________.
49. The mathematical expression that summarizes Charles’s law is:
V1
T1
=
V2
T2
50. If a 45.0-mL sample of gas at 26.5˚C is heated to 55.2˚C, what is the new volume of the gas
sample (at constant pressure)?
V1 = 45. 0 mL
V2 = ?
45. 0 mL = V2
45mL(328.2 K) = V2(299.5K)
T1 = 26.5 C = 299.5 K T2 = 55.2 C = 328.2 K 299.5 K
328.2K
V2 = 49.3 mL
51. The pressure of a sample of gas has increased (at constant volume); therefore, the
temperature of the sample of gas must have ___increased (direct relationship between P &
T)____________________.
52. The mathematical expression that shows the relationship between pressure and
temperature when volume is constant is:
P1
T1
=
P2
T2
53. A fully pressurized can of Dust-Off has a pressure of 600.0 kPa at 25˚C. The warning on the
can reads: “Do not expose to heat or store at temperatures above 130˚F.” Calculate the
potential pressure of the gas contained in the can of Dust-Off when it is heated from 25˚C to
54˚C (approximately 130˚F) assuming a constant volume of the can.
P1 = 600.0 kPa
P2 = ?
600.0 kPa = P2
600.0 kPa(298 K) = P2(327K)
T1 = 25 C = 298 K
T2 = 54 C = 327 K
298 K
327K
V2 = 658.4 kPa
54. The mathematical expression that shows the relationship between pressure, volume, and
temperature is:
P1V1
T1
=
P2V2
T2
55. The volume of a sample of oxygen is 300.0 mL when the pressure is 1.00 atm and the
temperature is 27.0⁰ C. At what temperature is the volume 1.00 L and the pressure 0.500 atm?
P1 = 1.00 atm
P2 = 0.500 atm
T1 = 27.0 C = 300 K T2 = ?
V1 = 300.0 mL
V2 = 1.00 L = 1000 mL
Volume units must match!!
1.00 atm (300.0 mL) =
0.500 atm (1000 mL)
300 K
T2
T2 (1.00 atm) (300.0 mL) = 0.500 atm (1000 mL)(300K)
T2 =500 K
56. Suppose that the pressure of 1.00 L of gas is 380.0 mm Hg when the temperature is 200.0
K. At what temperature is the volume 2.00 L and the pressure 0.750 atm.
.750 atm x 760 mmHg = 570 mmHg
380.0mmHg (1.00L) = (570 mmHg) (2.00L)
1 atm
200.0K
T2
T2 = 600K
57. In a mixture of gases, the pressure of the individual gases equals The sum of all of them.
58. The mathematical expression for Dalton’s Law of partial pressures is: Ptotal = P1 + P2 + P3
59. A tank contains a mixture of N2 at 2.1 atm, 02 at 3.0 atm, and He at 1.25 atm. What is the
total pressure within the tank?
2.1 atm + 3.0 atm + 1.25 atm = 6.35 atm
60. A sample of oxygen gas is collected by displacement of water at 25˚C and 775.2 mm Hg total
pressure. If the vapor pressure of water is 23.756 mm Hg at 25˚C, what is the partial pressure of
the oxygen gas in the sample? Ptotal = PO2 +PH2O
775.2 mmHg + PO2 + 23.756 mmHg
PO2 = 751.44 mmHg
61. The mathematical expression for the Ideal Gas Law is: PV = nRT
62. The variables in your answer to Question 61 above stand for: P = Pressure, V= Volume,
n = Number of moles, R = 8.314 L KPa/mole K, T = Temperature
63. Given each of the following sets of values for three of the gas variables, calculate the
unknown quantity:
a. P = 18152 kPa; V = 0.043 L; n = 0.421 mol; T = 223 K; R = 8.314kPa ∙ L/mol ∙ K
P (.043 L) = (.421 mole) (8.314 KPa L/K mole) (223 K)
b. P = 782 mm Hg; V = 5.02L ; n = 0.210 mol; T = 27˚C; R = 62.359 mm Hg ∙ L/mol ∙ K
(watch those units for temperature!)
782 mmHg (V) = .210 mole (62.359 mmHg) ( 301 K)
64. Of the following gases, which one will diffuse the fastest? (HINT: Calculate their molar
masses and then make your choice.)
O2
He
NO2
CH4
Fastest - He (4 g/mole), CH4 (16g/mole), O2 (32g/mole), NO2 (46g/mole) - Slowest
65. What are the basic assumptions of the kinetic molecular theory of gases?
Gases have mass, very small, do not have attractive forces towards each other, gas particles
are spread out, can be condensed, particles are in constant random motion
66. What happens to the number of collisions of the gas molecules in a closed container of
constant volume when the temperature is increased?
Increase in temperature = increase of collisions = increase in pressure
67. What is the relationship between volume and pressure of gases at constant temperature?
As the volume increase the pressure decreases

What would a graph of this relationship look like?

A sample of 50 mL of air is drawn into a syringe, and an airtight cap is placed over the
opening. The plunger on the syringe is drawn back to increase the volume to 100 mL.
What happens to the pressure?
The volume doubles of air doubles, so the pressure would decrease to one-half of the
original pressure
Back to moles and stoichiometry for the DuPage County Assessment
MOLES
1 mole = 6.02 x 1023 particles
1 mole = 22.4 Liters at standard temperature and pressure (STP)
1 moles = molar mass from the periodic table in grams
What does STP stand for?…give the full name and the values.
Standard Temperature and pressure. 0oC, 273 K, 1 atm, 101.3 kPa, 760 mmHg
1. Answer the question below, given the following balanced chemical equation:
2 H2 (g) + Cl2 (g) 
2 H2O (g)
Which of the following statements would NOT be the correct way to read this equation?
 2 moles of hydrogen gas reacts with 1 mole of chlorine gas to produce 2 moles of water
vapor.
 2 liters of hydrogen gas reacts with 1 liter of chlorine gas to produce 2 liters of water
vapor.
 1.204 x 1024 molecules of hydrogen gas reacts with 6.02 x 1023 molecules of chlorine gas
to produce 1.204 x 1024 molecules of water vapor.
 2 grams of hydrogen gas reacts with 1 gram of chlorine gas to produce 2 grams of
water vapor. (coefficients cannot stand for grams)
2. What is the molar mass for each of the substances below:
a. He 4.00 g/mole
b. LiOH 23.941 g/mole
c. Mg3(PO4)2 262.86 g/mole
3. If a crystal of CaCO3 has a mass of 10 grams, how many moles is this?
10 g CaCO3
x
1 mole
= .10 moles
100.078 g CaCO3
4. A balloon contains 0.15 L of helium at STP. How many atoms of He would this be?
How many grams? .15 L x 1 mole x
22.4 L
4.00g = .027 g He
1 mole
5. Answer the following questions given the equation below:
2SO2(g) + O2(g)  2SO3(g)
a. How many moles of O2 are needed to completely react with 4 moles of sulfur dioxide gas
(SO2)? 4 moles SO2 x 1 mole O2 =
2 moles O2
2 mole SO2
b. How many moles of SO2 would be needed to completely react with 2.5 moles of oxygen gas?
2.5 moles O2
x
2 mole SO2
=
5 moles SO2
1 mole O2
c. If 73 grams of SO2 completely reacted, how many liters of sulfur trioxide (SO3) would be
formed?
73 grams SO2
x
1 mole SO2 x
2 mole SO3
64.066 g SO2
2 mole SO2
x
22.4 L
=
25.5 L
1 mole SO3
6. What is the limiting reactant? The reactant that runs out first and limits how much product
can be made
7. What is the difference between the actual yield and the theoretical yield? The actual yield is
what you get when you are physically doing the lab. The theoretical yield is the calculated
amount of product that could be produced (use the limiting reagent to calculate the
theoretical yield)
ENERGY
6. What is the SI unit for heat energy? _______Joule____________________
7. What is the English unit for heat energy? ____British Thermal Unit_______
8. If you have a 10.0 g sample of gold and a 10.0 g sample of silver and a 10.0 g sample of iron,
which one would experience a greatest rise in temperature if they were all exposed to the same
amount of heat for exactly the same amount of time. Use the following table to help you
answer this question.
Metal
Iron
Silver
Gold
Specific Heat Capacity
(J/g⁰C)
0.449
0.233
0.126
9. State the Law of Conservation of Energy. Energy can neither be created nor destroyed
10. An ice cube at -5⁰C is heated to a temperature of 10⁰C.
a. Would the melting of the ice cube be an endothermic or exothermic process?
b. What could you say about the total energy involved in this ice/water system? The total
system is absorbing energy. When calculating, there will be two equations involving kinetic
energy and one involving potential.
11. Bond breaking is an ___Endothermic___ process, while bond formation is
an ____Exothermic__process.
12. Define the following terms and then state, where appropriate, whether the process is an
exothermic or endothermic process.






Endothermic: reactions where the net energy of the reaction is absorbed
Exothermic: reactions where the net energy of the reaction is released
Sublimation: Phase change from the solid to gaseous state
Freezing: Also known as Fusion, the Phase change from the liquid to solid state
Condensation: Phase change from the Gas to liquid state
Vaporization: Phase change from the liquid to gaseous state
13. A penny is heated then submerged in cool water. What will happen to the temperature of
the water? ___Increase___Temperature of the
penny? ___Decrease____
14. Given the following equation: C3H8 + 5O2 
3CO2 + 4H2O + energy
Is this an endothermic or an exothermic reaction?
Is energy being absorbed or released?
15. Know how to interpret a heating curve.
a. Where would you find phase changes (2 regions)? Segments 2 & 4
b. Where would you use the equation q = mcΔT? Segments 1, 3 & 5
c. Where would you use the molar heat of fusion (ΔHfus)? Segment 2
d. Where would you find a solid only? Segment 1 A gas only? Segment 5
e. In which 2 regions is the temperature constant? Segment 2 & 4
16. How much energy is needed (in joules) to raise the temperature of 50.0 g of water from 20⁰C to
80⁰C? (The specific heat of water is 4.18 J/g⁰C.)
q=mcT
=50.0g * 4.18 J/g⁰C * (80⁰C - 20⁰C)
=12540J