CHEM 1115 Comprehensive Final Exam Review Problems

1. A 12.5 mL sample of liquid has a mass of 10.897 g. What is the density of the liquid?

2. What is the mass of a 5.0 cm³ piece of metal if its density is 8.91 g/cm³?

3. What volume of a liquid with a density of 0.890 g/mL is needed to provide 25.000 g?

4. Convert 1.90 x 10⁵ mm to km using dimensional analysis.

5. Classify the following as (1) metal, nonmetal or metalloid; (2) main group, transition metal, lanthanide, or actinide; (3) alkali metal, alkaline earth metal; halogen, noble gas, or none of these.

a. hydrogen

b. zinc

c. bromine

d. neon

e. sodium

f. uranium

g. magnesium

6. Write the formulas for the following compounds:

a. sodium phosphate

b. aluminum carbonate

c. calcium bromide

d. diphosphorus pentoxide

e. iron (III) oxide

f. potassium sulfate

g. copper (II) nitrate

h. sulfur trioxide

i. zinc hydroxide

j. carbon tetrachloride

7. Balance the following equation.

C₃H₆ + O₂ à CO₂ + H₂O

8. Given the following equation: N₂ + 3 H₂ à 2 NH₃

a. How many moles of hydrogen are needed to react completely with 0.25 moles of nitrogen?

b. How many grams of ammonia can be produced using 1.5 moles of hydrogen?

c. How many grams of ammonia can be produced using 15.0 g of nitrogen?

9. What is the molarity of a solution prepared by dissolving 25.0 g of sodium hydroxide in enough water to make 1250 mL of solution?

10. Write a balanced equation for the following reactions which occur in aqueous solution. Be sure to use the correct physical states for all reactants and products.

a. silver sulfate and sodium carbonate

b. barium hydroxide and ammonium phosphate

c. sulfuric acid and potassium hydroxide

11. Write the net ionic equation for each reaction given in question 9.

12. Calculate the concentration of a hydrochloric acid solution that was prepared by diluting 25.0 mL of 2.20 M HCl to a volume of 250.0 mL.

13. Calculate the volume in mL of 6.0 M HCl needed to prepare 1.20 L of 2.12 M HCl.

14. How many mL of 0.125 M calcium hydroxide are needed to react with 10.0 g of acetic acid?

15. How many mL of 0.125 M sodium hydroxide are needed to react completely with 25.0 mL of 0.10 M phosphoric acid?

16. Describe how the volume of a sample of gas changes when the following changes occur (assuming that the other two variables are constant)

a. pressure decreases

b. temperature decreases

c. amount of gas decreases

17. Describe how the pressure of a sample of gas changes when the following changes occur (assuming that the other two variables are constant).

a. volumes increases

b. temperature increases

c. amount of gas increases

18. What is the volume of 1.5 moles of a gas at 1.25 atm and 65^oC? (R = 0.08206 atm^.L/mol^.K)?

19. A sample of gas in a sealed container at 1.15 atm and 52^oC is heated until the pressure reaches 2.06 atm. What is the temperature of the gas in ^oC?

20. Identify the name and symbol for the quantum number that gives the following information about an orbital in the quantum mechanical model. Indicate the values each one can have:

a. shape

b. energy

c. orientation in space

21. Draw an orbital diagram for silicon.

22. Write the electron configuration for selenium.

23. Write the electron configuration using core notation for:

a. cesium

b. cesium ion

c. iodine

d. iodide ion

24. Which of the following ions (or atoms) is the smallest:

a. Mg²⁺ or Ba²⁺

b. O or O^2-

c. Na or Ar

25. For each of the following compounds or ions, draw one valid Lewis structure and give the name of its electron domain and molecular geometries.

a. ICl₂^-

b. carbon dioxide

c. chlorine trifluoride

d. ammonia

e. bromine pentafluoride

f. nitrate ion

26. The specific heat of aluminum is 0.900 J/g^.K. Use this information to answer the questions below.

a. Calculate the amount of heat needed to raise the temperature of 125 grams of aluminum from 22.7^oC to 85.6^oC.

b. If 1.72 kJ of heat are added to 165 g of aluminum, calculate the temperature change that would occur.

c. If the initial temperature for the aluminum described in part b is 19.7^oC, what will its final temperature be?

27. Calculate the specific heat of gasoline if 4440 J of heat are needed to raise the temperature of 100.0 g of gasoline from 19.3^oC to 39.3^oC.

28. The heat of vaporization for water is 40.7 kJ/mole. Calculate the amount of heat needed to convert 75.0 g of water at 100^oC to steam at the same temperature.

29. The heat of fusion of water is 6.01 kJ/mole. Calculate the amount of heat needed to convert 127.5 g of ice at 0^oC to water at the same temperature.

30. The heat of fusion of water is 6.01 kJ/mole. Calculate the enthalpy change that occurs when 127.5 g of water at 0^oC is converted to ice at the same temperature.

31. The combustion of methylhydrazine (CH₆N₂) is described by the following thermochemical equation. Use this information to answer the questions below.

2 CH₆N₂ (l) + 5 O₂ (g) à 2 N₂ (g) + 2 CO₂ (g) + 6 H₂O (l) DH = -2.60 x 10³ kJ

a. Is the reaction endothermic or exothermic?

b. Is heat gained or lost during combustion?

c. Calculate the enthalpy change that occurs during the combustion of 1.55 kg of methylhydrazine.

d. Calculate the enthalpy change that occurs when 2.85 moles of water are formed by the combustion of methylhydrazine.

e. What is the enthalpy change for the following reaction?

2 N₂ (g) + 2 CO₂ (g) + 6 H₂O (l) à 2 CH₆N₂ (l) + 5 O₂ (g)

32. Identify each of the following phase changes as endothermic or exothermic.

a. vaporization

b. melting

c. condensation

d. freezing

e. sublimation

33. Use the phase diagram below to answer the following questions.

a. What phase change occurs going from point B to A?

b. What phase change occurs going from pont G to H?

c. What physical state(s) is/are present at point F?

d. What physical state(s) is/are present at point D?

e. What physical state(s) is/are present at point E?

f. Which point represents the triple point of the substance?