Name ______Period ______

CP Chemistry – Problem Final Exam – Practice Problems

Directions: Answer the following questions, and circle the correct response. Show all

work legibly! This way you can receive partial credit on the

final exam for your effort. Circled answers with no work will receive a

zero.

1. Calculate the [H3O+] ion concentration given the [OH-] concentration to be

6.8 x 10-10 M.

a.6.8 x 10-10 M

b.1.5 x 10-5 M

c.6.8 x 10-24 M

d.6.0 x 104 M

2.How many moles of helium are contained in a 5.00 L canister at 4.50 atm and

303K?

a.0.904

b.2.10

c.3.45

d.6.70

3.A solution consists of 54.0 g NaCl and 178 g water. What is the % by mass of the

NaCl component of the solution?

a.54%

b.30%

c.3.3%

d.23%

4. What is the hydroxide ion concentration, [OH-(aq)] of a solution having a pH of 3?

a.1 x 10-1 M

b.1 x 10-3 M

c.1 x 10-11 M

d.3 x 100 M

5. A helium-filled balloon has a volume of 20.0 L at 45.0°C and 1.28 atm. What

volume will it have at 0.855 atm and 10.0°C?

a.4.00 L

b.16.0 L

c.26.6 L

d.32.2 L

6. The mass of 12.6 L of gaseous ammonia (NH3), measured at STP, is

a.1.01 g

b.9.59 g

c.17.0 g

d.282 g

7. Bacteria produce methane gas in sewage-treatment plants. This gas is often

captured or burned. If a bacterial culture produces 60.0 mL of methane gas at

600.0 mm Hg, what volume would be produced at 760.0 mm Hg (Temperature

constant)?

a.32 mL

b.40 mL

c.47 mL

d.60 mL

8. The half- life of thorium – 234 is 24 days. If you start with a 42.0 g sample of

thorium-234, how much will remain after 72 days?

a.2.63 g

b.5.25 g

c.10.5 g

  1. 21.0 g

9. What mass of nitrogen gas, N2, will react to form 2.50 L of ammonia, NH3, at STP?

N2 (g) + 3H2 (g)  2 NH3 (g)

a.2.50 g

b.1.56 g

c.12.3 g

d.0.89 g

10. A mixture of three gases has a total pressure of 1.25 atm. If the hydrogen

gas has a pressure of 0.50 atm and the nitrogen gas has a pressure

of 0.40 atm, what is the partial pressure exerted by the third gas?

  1. 0.50 atm
  2. 0.35 atm
  3. 1.75 atm
  4. 0.40 atm