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CLEP Chemistry Practice Test

10 free sample questions with answers and explanations. See how you'd score on the real CLEP exam.

Question 1Unit 1: Atomic Structure and Periodicity

If 50 mL of 0.2 M HCl is mixed with 50 mL of 0.2 M NaOH, what is the resulting concentration of NaCl?

A
A) 0.05 M
B
B) 0.1 M
C
C) 0.2 M
D
D) 0.4 M
E
E) 0.5 M

Explanation

0.1 is correct because HCl and NaOH react in a 1:1 ratio, so the number of moles of NaCl formed will be equal to the number of moles of either reactant, which is 0.2 M * 0.05 L = 0.01 mol, and the total volume is 100 mL or 0.1 L, so the concentration is 0.01/0.1 = 0.1 M.

Question 2Unit 1: Atomic Structure and Periodicity

A gas occupies 25 mL at 1 atm and 20°C. If the pressure is doubled, what will be the new volume?

A
A) 10 mL
B
B) 12.5 mL
C
C) 25 mL
D
D) 37.5 mL
E
E) 50 mL

Explanation

12.5 is correct because by Boyle's Law, P1V1 = P2V2, and since P2 = 2P1, then V2 = V1/2 = 25/2 = 12.5 mL.

Question 3Unit 1: Atomic Structure and Periodicity

What is the pH of a solution with [H+] = 0.01 M?

A
A) 1
B
B) 2
C
C) 3
D
D) 4
E
E) 5

Explanation

2 is correct because pH = -log[H+], so pH = -log(0.01) = 2.

Question 4Unit 1: Atomic Structure and Periodicity

A gas occupies 25L at 1.2atm. What is its volume at 0.8atm, assuming constant temperature?

A
A) 30L
B
B) 32L
C
C) 37.5L
D
D) 40L
E
E) 45L

Explanation

37.5L is correct because by Boyle's Law, P1V1 = P2V2, so V2 = V1 * P1 / P2 = 25L * 1.2atm / 0.8atm = 37.5L.

Question 5Unit 1: Atomic Structure and Periodicity

What is the value of log(100) with base 10?

A
A) 1
B
B) 2
C
C) 3
D
D) 4
E
E) 5

Explanation

2 is correct because log(100) with base 10 asks 'what power of 10 equals 100', and 10² = 100, so the answer is 2.

Question 6Unit 1: Atomic Structure and Periodicity

A 500ml sample of water has a mass of 520g. What is its density in g/ml?

A
A) 0.9
B
B) 1.0
C
C) 1.04
D
D) 1.1
E
E) 1.2

Explanation

1.04 is correct because density is mass per unit volume, so density = mass / volume = 520g / 500ml = 1.04g/ml.

Question 7Unit 1: Atomic Structure and Periodicity

What is the sum of the atomic numbers of helium and oxygen?

A
A) 6
B
B) 8
C
C) 10
D
D) 12
E
E) 14

Explanation

10 is correct because helium has an atomic number of 2 and oxygen has an atomic number of 8, and 2 + 8 = 10.

Question 8Unit 1: Atomic Structure and Periodicity

What is the function of a hot plate in a laboratory?

A
A) To cool a substance
B
B) To mix a solution
C
C) To heat a substance
D
D) To weigh a substance
E
E) To filter a solution

Explanation

A hot plate is used to heat a substance because it provides a controlled source of heat, allowing for the heating of substances to a specific temperature, which is essential in many laboratory experiments.

Question 9Unit 1: Atomic Structure and Periodicity

Which lab equipment is used to determine the concentration of a solution by measuring the amount of light absorbed?

A
A) Spectrophotometer
B
B) Chromatography column
C
C) Distillation apparatus
D
D) Centrifuge
E
E) Microscope

Explanation

A spectrophotometer is used to determine the concentration of a solution by measuring the amount of light absorbed because it applies the Beer-Lambert law, which relates the absorption of light to the concentration of the solution.

Question 10Unit 1: Atomic Structure and Periodicity

What is the purpose of a pipette in a laboratory setting?

A
A) To measure the temperature of a substance
B
B) To weigh a substance
C
C) To transfer a precise volume of liquid
D
D) To stir a mixture
E
E) To filter a solution

Explanation

A pipette is used to transfer a precise volume of liquid because it allows for accurate measurement and transfer of small volumes of liquids, which is essential in many laboratory experiments.

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