CHEM2120 Complete Study Guide| Notes,
Exams & Solutions
1. What is true at chemical equilibrium?
❖ the forward reaction rate is equal to the reverse reaction rate
2. A sample of a substance burns more rapidly in pure oxygen than in air. Which
factor is most responsible for this high rate of reaction?
❖ the concentration of the reactants
3. What statements accurately describe kinetic molecular theory? Select all that apply.
❖ The mobility of particles is dependent on their kinetic energy.
Matter is made up of particles.
4. What does Le Châtelier's principle state about a disturbance to a chemical reaction?
❖ The equilibrium position of a reaction shifts to minimize the disturbance.
5. 950 J of energy is used to heat an unknown mass of copper from 20.0° C to 95.0° C.
The specific heat of copper = 0.39 J/(g·°C).
What is the mass of the copper?
❖ 32
6. A sample of oxygen gas has a volume of 2.1 L at 3.6 atm pressure and 200 K
temperature.
What would the volume of this sample be at 1.0 atm and 400 K?
❖ 15.1
7. Study the table of polar and nonpolar substances.
If the substance X is known to be nonpolar, which of the other substances are also
nonpolar?
❖ Z and Q
8. Study the reaction.CH44 + 2O22 → CO22 + 2H22OIf 7.4 moles of carbon dioxide
(CO22) form at the end of the reaction, how many moles of methane (CH44) and
oxygen gas (O22) entered the reaction?
❖ 7.4 moles of methane and 14.8 moles of oxygen gas
9. Americium-241 is a radioactive isotope used in household smoke detectors. It decays
by alpha decay. Which of the following describes the properties of this radiation?
Select all that apply.
❖ positively charged
made of 4 particles joined together
unlikely to escape the smoke detector
,10. What describes the emissions of an isotope that gives off both beta and gamma
radiation?
❖ negatively charged particles and high energy photons
11. Which of the following describes a nuclear fusion reaction?
❖ Two nuclei with low mass combine to form one larger nucleus.
12. What can be concluded from the following phase diagram?
❖ There exists a temperature and pressure combination at which all 3 phases of the
substance can exist in equilibrium at once.
13. A sealed container of liquid develops some vapor pressure. Which of the following
would reduce the vapor pressure?
❖ decrease the temperature
14. What happens when there is an increase in temperature for a reaction rate?
Select all that apply.
❖ It increases the total number of molecular collisions that occur
It increases the percentage of collisions that result in a reaction
15. What is latent heat of condensation?
❖ the amount of heat released when a certain mass of a substance changes from a gas to a
liquid
16. The greater the average kinetic energy of the particles in a sample of matter,
__________.
❖ the higher the temperature
17. Why do water molecules tend to stick to each other to form a liquid?
❖ The exposed charge on hydrogen's protons are attracted to unshared electron pairs on
oxygen atoms.
18. A solution is formed by dissolving 83.2 grams of copper II chloride (CuCl22) in 2.5
liters of water. The molar mass of CuCl22 is 134.45 g/mol.
What is the molarity of the solution?
❖ 0.25
19. A mixture consists of 45% oxygen, 12% argon, and 43% nitrogen by volume. A
sample of this mixture has a pressure of 2.0 atm in a 5.3 L container at 350 K
temperature. How many moles of gas are in the container?
❖ 0.369
20. What type of reaction is shown in the graph, and why?
❖ Exothermic: Energy is released to the environment during the formation of the products.
21. Examine the image, which shows four chemical systems of colliding molecules.
Which chemical system has the highest reaction rate?
❖ D
22. Study the following equation.Fe(s) + 2 HCl(aq) ⇌ H22(g) + FeCl22(aq)
What happens to the iron metal when it is reacted in a closed container to produce
, hydrogen gas in this manner?
Select all that apply.
❖ The rate of the forward reaction is at its maximum when the reaction first starts.
The rate of the reverse reaction increases as hydrogen gas accumulates.
23. How many pictograms are in the Global Harmonized System?
❖ Fire extinguisher
eyewash station
safety shower
24. When are you allowed to go without safety glasses/goggles in the lab?
❖ never
25. Iron has a density of 7.9 g/cm3. What is the mass of a cube of iron with the length of
one side equal to 55.0 mm?
❖ 1.3 x 103 g
26. Of the following, which is the smallest mass?
❖ 2.5 x 109 fg
27. How many significant figures are in the measurement 5.34 g?
❖ 3
28. What is the SI unit for mass?
❖ kilogram
29. The correct answer (reported to the proper number of significant figures) to the
following multiplication is, 12.75 × 1.3621 =
❖ 17.37
30. The density of a 167.4 g sample of magnesium having a volume of 96.32 ml is
__________ g/cm3.
❖ 1.738
31. Two students measured volume of the given liquid sample four times. Their results
are tabulated below. The exact volume of the liquid is 11.5 mL, whose measurement
is more accurate?
❖ Student A measurement is more accurate than Student B.
32. The density of silver is 10.5 g/cm3. A piece of silver with a mass of 125 g would
occupy a volume of __________ cm3.
❖ 11.9
33. The correct answer (reported to the proper number of significant figures) to the
following is (12.67 + 19.2)(3.99) / (1.36 + 11.366) = _____
❖ 9.99
34. How many liters of wine can be held in a wine barrel whose capacity is 26.0 gal?
❖ 98.4
35. Choose the correct name and charges of the cation and anion of compound
CaO__________
Exams & Solutions
1. What is true at chemical equilibrium?
❖ the forward reaction rate is equal to the reverse reaction rate
2. A sample of a substance burns more rapidly in pure oxygen than in air. Which
factor is most responsible for this high rate of reaction?
❖ the concentration of the reactants
3. What statements accurately describe kinetic molecular theory? Select all that apply.
❖ The mobility of particles is dependent on their kinetic energy.
Matter is made up of particles.
4. What does Le Châtelier's principle state about a disturbance to a chemical reaction?
❖ The equilibrium position of a reaction shifts to minimize the disturbance.
5. 950 J of energy is used to heat an unknown mass of copper from 20.0° C to 95.0° C.
The specific heat of copper = 0.39 J/(g·°C).
What is the mass of the copper?
❖ 32
6. A sample of oxygen gas has a volume of 2.1 L at 3.6 atm pressure and 200 K
temperature.
What would the volume of this sample be at 1.0 atm and 400 K?
❖ 15.1
7. Study the table of polar and nonpolar substances.
If the substance X is known to be nonpolar, which of the other substances are also
nonpolar?
❖ Z and Q
8. Study the reaction.CH44 + 2O22 → CO22 + 2H22OIf 7.4 moles of carbon dioxide
(CO22) form at the end of the reaction, how many moles of methane (CH44) and
oxygen gas (O22) entered the reaction?
❖ 7.4 moles of methane and 14.8 moles of oxygen gas
9. Americium-241 is a radioactive isotope used in household smoke detectors. It decays
by alpha decay. Which of the following describes the properties of this radiation?
Select all that apply.
❖ positively charged
made of 4 particles joined together
unlikely to escape the smoke detector
,10. What describes the emissions of an isotope that gives off both beta and gamma
radiation?
❖ negatively charged particles and high energy photons
11. Which of the following describes a nuclear fusion reaction?
❖ Two nuclei with low mass combine to form one larger nucleus.
12. What can be concluded from the following phase diagram?
❖ There exists a temperature and pressure combination at which all 3 phases of the
substance can exist in equilibrium at once.
13. A sealed container of liquid develops some vapor pressure. Which of the following
would reduce the vapor pressure?
❖ decrease the temperature
14. What happens when there is an increase in temperature for a reaction rate?
Select all that apply.
❖ It increases the total number of molecular collisions that occur
It increases the percentage of collisions that result in a reaction
15. What is latent heat of condensation?
❖ the amount of heat released when a certain mass of a substance changes from a gas to a
liquid
16. The greater the average kinetic energy of the particles in a sample of matter,
__________.
❖ the higher the temperature
17. Why do water molecules tend to stick to each other to form a liquid?
❖ The exposed charge on hydrogen's protons are attracted to unshared electron pairs on
oxygen atoms.
18. A solution is formed by dissolving 83.2 grams of copper II chloride (CuCl22) in 2.5
liters of water. The molar mass of CuCl22 is 134.45 g/mol.
What is the molarity of the solution?
❖ 0.25
19. A mixture consists of 45% oxygen, 12% argon, and 43% nitrogen by volume. A
sample of this mixture has a pressure of 2.0 atm in a 5.3 L container at 350 K
temperature. How many moles of gas are in the container?
❖ 0.369
20. What type of reaction is shown in the graph, and why?
❖ Exothermic: Energy is released to the environment during the formation of the products.
21. Examine the image, which shows four chemical systems of colliding molecules.
Which chemical system has the highest reaction rate?
❖ D
22. Study the following equation.Fe(s) + 2 HCl(aq) ⇌ H22(g) + FeCl22(aq)
What happens to the iron metal when it is reacted in a closed container to produce
, hydrogen gas in this manner?
Select all that apply.
❖ The rate of the forward reaction is at its maximum when the reaction first starts.
The rate of the reverse reaction increases as hydrogen gas accumulates.
23. How many pictograms are in the Global Harmonized System?
❖ Fire extinguisher
eyewash station
safety shower
24. When are you allowed to go without safety glasses/goggles in the lab?
❖ never
25. Iron has a density of 7.9 g/cm3. What is the mass of a cube of iron with the length of
one side equal to 55.0 mm?
❖ 1.3 x 103 g
26. Of the following, which is the smallest mass?
❖ 2.5 x 109 fg
27. How many significant figures are in the measurement 5.34 g?
❖ 3
28. What is the SI unit for mass?
❖ kilogram
29. The correct answer (reported to the proper number of significant figures) to the
following multiplication is, 12.75 × 1.3621 =
❖ 17.37
30. The density of a 167.4 g sample of magnesium having a volume of 96.32 ml is
__________ g/cm3.
❖ 1.738
31. Two students measured volume of the given liquid sample four times. Their results
are tabulated below. The exact volume of the liquid is 11.5 mL, whose measurement
is more accurate?
❖ Student A measurement is more accurate than Student B.
32. The density of silver is 10.5 g/cm3. A piece of silver with a mass of 125 g would
occupy a volume of __________ cm3.
❖ 11.9
33. The correct answer (reported to the proper number of significant figures) to the
following is (12.67 + 19.2)(3.99) / (1.36 + 11.366) = _____
❖ 9.99
34. How many liters of wine can be held in a wine barrel whose capacity is 26.0 gal?
❖ 98.4
35. Choose the correct name and charges of the cation and anion of compound
CaO__________
