10 free sample questions with answers and explanations. See how you'd score on the real CLEP exam.
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?
0.05 M
0.5 M
0.1 M
0.2 M
0.4 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.
A gas occupies 25 mL at 1 atm and 20°C. If the pressure is doubled, what will be the new volume?
10 mL
12.5 mL
50 mL
25 mL
37.5 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.
What is the pH of a solution with [H+] = 0.01 M?
1
2
3
4
5
Explanation
2 is correct because pH = -log[H+], so pH = -log(0.01) = 2.
A gas occupies 25L at 1.2atm. What is its volume at 0.8atm, assuming constant temperature?
30L
32L
40L
37.5L
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.
A 500ml sample of water has a mass of 520g. What is its density in g/ml?
0.9
1.0
1.04
1.1
1.2
Explanation
1.04 is correct because density is mass per unit volume, so density = mass / volume = 520g / 500ml = 1.04g/ml.
What is the sum of the atomic numbers of helium and oxygen?
6
8
10
12
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.
What is the function of a hot plate in a laboratory?
To cool a substance
To mix a solution
To weigh a substance
To heat a substance
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.
Which lab equipment is used to determine the concentration of a solution by measuring the amount of light absorbed?
Spectrophotometer
Chromatography column
Distillation apparatus
Centrifuge
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.
What is the purpose of a pipette in a laboratory setting?
To measure the temperature of a substance
To transfer a precise volume of liquid
To weigh a substance
To stir a mixture
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.
Which piece of lab equipment is used to separate a mixture based on differences in boiling points?
Chromatography column
Spectrophotometer
Distillation apparatus
Centrifuge
Microscope
Explanation
A distillation apparatus is used to separate a mixture based on differences in boiling points because it allows for the separation of components based on their boiling points, making it a crucial tool in purification processes.