MULTIPLE CHOICE (2 points each)
Choose the letter of the answer that is the best choice for each question or statement.

1. A chemical equation is balanced when
a. The total number of molecules is the same in reactants and products
b. The total number of ions is the same in reactants and products
c. The sum of the coefficients of the reactants is equal to the sum of the coefficients of the products
d. The number of atoms of each element is the same in the reactants and products
e. The charge on each atom is the same in reactants and products

Pentane, C5H12, reacts with oxygen, O2, to form carbon dioxide, CO2, and water, H2O, according to the following reaction. Answer questions 2 thru 4 about this reaction.

C5H12 + ? O2 --> ? CO2 + ? H2O

2. What is the coefficient for oxygen in the balanced equation?
a. 2
b. 4
c. 5
d. 6
e. 8

3. What is the coefficient for carbon dioxide in the balanced equation?
a. 2
b. 4
c. 5
d. 6
e. 8

4. What is the coefficient for water in the balanced equation?
a. 2
b. 4
c. 5
d. 6
e. 8

5. What is the classification for this reaction?

SO3 + H2O --> H2SO4

a. decomposition
b. combination
c. single replacement
d. double replacement
e. oxidation reduction

6. What is the classification for this unbalanced reaction?

Fe + HCl --> FeCl3 + H2

a. dehydration
b. combination
c. decomposition
d. single replacement
e. double replacement

7. Calculate the molar mass of magnesium chloride.
a. 24.3 g
b. 95.2 g
c. 125.9 g
d. 59.8 g
e. 70.0 g

8. 3.00 moles of NO2 have a mass of
a. 138 g
b. 46.0 g
c. 30.0 g
d. 90.0 g
e. 45.0 g

9. The molar mass of C3H8O2 is
a. 76.0 g
b. 60.0 g
c. 29.0 g
d. 69.0 g
e. 52.0 g

10. Avogadroâ€™s number is the number of
a. Particles in 1 mole of a substance
b. Amu in 1 mole of a substance
c. Grams in 1 mole of a substance
d. Moles in 6.02 x 1023 grams of an element
e. Moles in 6.02 x 1023 amu of an element

11. The force of gas particles against the walls of a container is called _____ .
a. Pressure
b. Volume
c. Temperature
d. Quantity of gas
e. Density

12. A 5.00 L tank contains helium gas at 1.50 atm. What is the pressure of the gas in mmHg?
a. 1.50 mmHg
b. 507 mmHg
c. 760 mmHg
d. 1140 mmHg
e. 3800 mmHg

13. The volume of a gas with a pressure of 1.2 atm increases from 1.0 L to 4.0 L. What is the final pressure of the gas, assuming constant temperature and amount of gas?
a. 1.2 atm
b. 0.30 atm
c. 3.3 atm
d. 4.8 atm
e. 1.0 atm

14. Complete the following statement: In Charlesâ€™ law, the volume of a gas _____ when the _____ decreases.
a. Increases, temperature
b. Increases, quantity of gas
c. Increases, pressure
d. Decreases, temperature
e. Decreases, pressure

15. A diver exhales a bubble with a volume of 250 mL at a pressure of 2.5 atm and a temperature of 15 OC. What is the volume of the bubble when it reaches the surface where the pressure is 1.0 atm and the temperature is 27 OC?
a. 580 mL
b. 630 mL
c. 100 mL
d. 110 mL
e. 1100 mL

Problem Solving. Be sure to show all work when applicable.

16. How many mole(s) is/are 9.28 x 10Â²â´ atoms of magnesium? (5 pts.)

17. How many molecules are in 0.854 mole of carbon dioxide? (5 pts.)

18. How many grams are in 1.15 moles of silver? (5 pts.)

19. Calculate the molar mass in the following: (1 pt. each, 5 pts. total)

a. O2

b. CaF2

c. C2H6

d. Na3PO4

e. (NH4)2SO3

20. Calculate the mass of 1.86 x 10Â²Â¹ particles of Al(OH)3. (10 pts.)

21. Provide the balanced chemical reaction for the single replacement reaction of aluminum chloride with bromine. (5 pts.)

22. For the reactions below, determine the type of reaction, complete the reaction and balance the reaction: (3 pts. each)

a. C2H6 + O2 ---> type:

b. Ag2SO3 + NaCl ---> type:

c. K2CO3 ---> CO2 + ___ type:

d. Al2O3 + Sr --> type:

e. Li + I2 --> type:

23. If 6.2 L of gas at 723 mmHg at 25.0 OC is compressed to 4.0 L at 4117 mmHg, what is the final temperature of the gas, celsius? (5 pts.)

24. What is the pressure inside a can, in mmHg, if it is heated from 15 Â°C at 1.0 atm to 115 Â°C? (5 pts.)

25. How many grams of nitrogen are in a 1.7 L balloon that has a pressure of 1.8 atm if the balloon is at room temperature (25.3 Â°C)? (10 pts)

MULTIPLE CHOICE (2 points each) Choose the letter of the answer th...