Free CLEP Chemistry Practice Test (2026)

Question 1

Why are many compounds of transition metals, such as copper(II) sulfate, colored?

Accepted Answer

Electrons in partly filled d orbitals absorb certain wavelengths of visible light as they move between d energy levels.

Answer

The metal ions are radioactive and give off light continuously.

Answer

Transition metal ions have completely filled d subshells that reflect all visible light.

Answer

The color always comes from the anion, never from the metal ion.

Answer

Transition metal compounds have unusually strong metallic bonds.

Question 2

A student heats 2.50 g of a copper(II) sulfate hydrate, CuSO₄·xH₂O, until all the water is driven off, leaving 1.60 g of anhydrous CuSO₄. What is x? (molar masses: CuSO₄ 159.6 g/mol, H₂O 18.0 g/mol)

Accepted Answer

5

Answer

2

Answer

3

Answer

7

Answer

9

Question 3

A container holds a mixture of H₂ and O₂ gases at the same temperature. Which quantity is the same for the two kinds of molecules?

Accepted Answer

Average kinetic energy

Answer

Average speed

Answer

Root-mean-square speed

Answer

Molar mass

Answer

Rate of effusion

Question 4

Use these standard enthalpies of formation (kJ/mol): CH₄(g) −74.8, CO₂(g) −393.5, H₂O(l) −285.8. What is ΔH° for CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(l)?

Accepted Answer

−890.3 kJ

Answer

−604.5 kJ

Answer

−1039.9 kJ

Answer

+890.3 kJ

Answer

−754.1 kJ

Question 5

For the endothermic reaction N₂O₄(g) ⇌ 2NO₂(g), what happens when the temperature of the equilibrium mixture is raised?

Accepted Answer

The equilibrium shifts toward NO₂, and K increases.

Answer

The equilibrium shifts toward NO₂, but K stays the same.

Answer

The equilibrium shifts toward N₂O₄, and K decreases.

Answer

Nothing changes, because temperature affects only the reaction rate.

Answer

The equilibrium shifts toward N₂O₄, but K stays the same.

Question 6

Which oxide is amphoteric, reacting with both strong acids and strong bases?

Accepted Answer

Al₂O₃

Answer

Na₂O

Answer

MgO

Answer

SO₃

Answer

CO₂

Question 7

Which is the net ionic equation for the reaction of aqueous acetic acid, a weak acid, with aqueous sodium hydroxide?

Accepted Answer

CH₃COOH(aq) + OH⁻(aq) → CH₃COO⁻(aq) + H₂O(l)

Answer

H⁺(aq) + OH⁻(aq) → H₂O(l)

Answer

CH₃COOH(aq) + NaOH(aq) → CH₃COONa(aq) + H₂O(l)

Answer

CH₃COO⁻(aq) + Na⁺(aq) → CH₃COONa(s)

Answer

CH₃COOH(aq) + Na⁺(aq) → CH₃COONa(aq) + H⁺(aq)

Question 8

Molten sodium chloride is electrolyzed using inert electrodes. What happens at the cathode?

Accepted Answer

Na⁺ ions gain electrons and form sodium metal.

Answer

Cl⁻ ions lose electrons and form chlorine gas.

Answer

Water is reduced to hydrogen gas.

Answer

Sodium atoms lose electrons and form Na⁺ ions.

Answer

Chlorine gas gains electrons and forms Cl⁻ ions.

Question 9

A sample of gas occupies 6.00 L at 27 °C and 1.00 atm. What volume does it occupy at 127 °C and 2.00 atm, if the amount of gas does not change?

Accepted Answer

4.00 L

Answer

2.25 L

Answer

14.1 L

Answer

16.0 L

Answer

3.00 L

Question 10

At 25 °C, which liquid has the highest vapor pressure?

Accepted Answer

Diethyl ether, CH₃CH₂OCH₂CH₃

Answer

Water, H₂O

Answer

Ethanol, CH₃CH₂OH

Answer

Ethylene glycol, HOCH₂CH₂OH

Answer

Glycerol, HOCH₂CH(OH)CH₂OH

Question 11

A solution contains 0.50 mol of a nonvolatile nonelectrolyte dissolved in 4.50 mol of water at 25 °C. Pure water has a vapor pressure of 23.8 torr at this temperature. What is the vapor pressure of the solution?

Accepted Answer

21.4 torr

Answer

21.2 torr

Answer

2.38 torr

Answer

23.8 torr

Answer

26.4 torr

Question 12

Which of these period 2 elements has the highest first ionization energy: Be, B, C, N or O?

Accepted Answer

N

Answer

O

Answer

C

Answer

Be

Answer

B

Question 13

How many sigma (σ) and pi (π) bonds are in a molecule of acrylonitrile, CH₂=CH–C≡N?

Accepted Answer

6 σ and 3 π

Answer

9 σ and 0 π

Answer

6 σ and 2 π

Answer

5 σ and 3 π

Answer

3 σ and 6 π

Question 14

In the compound [Co(NH₃)₄Cl₂]Cl, what are the oxidation state and the coordination number of cobalt?

Accepted Answer

+3 and 6

Answer

+3 and 4

Answer

+2 and 6

Answer

+1 and 6

Answer

+3 and 7

Question 15

What is the pH of a 0.10 M solution of a weak acid HA with Ka = 1.0 × 10⁻⁵?

Accepted Answer

3.00

Answer

1.00

Answer

5.00

Answer

2.50

Answer

6.00

Question 16

Which compound is a structural isomer of butanal, CH₃CH₂CH₂CHO?

Accepted Answer

Butanone, CH₃COCH₂CH₃

Answer

1-Butanol, CH₃CH₂CH₂CH₂OH

Answer

Propanoic acid, CH₃CH₂COOH

Answer

Butanoic acid, CH₃CH₂CH₂COOH

Answer

Diethyl ether, CH₃CH₂OCH₂CH₃

Question 17

A student rinses a buret with distilled water but not with the NaOH solution, then fills it with the NaOH and titrates an acid. How does this mistake affect the calculated concentration of the acid?

Accepted Answer

It is too high, because the NaOH was diluted, so more volume was needed.

Answer

It is too low, because the NaOH was diluted, so less volume was needed.

Answer

It is unaffected, because water does not react with the acid.

Answer

It is too low, because the water neutralized some of the acid.

Answer

It is too high, because the water made the NaOH more concentrated.

Question 18

A mixture of 4.0 g of H₂ and 16.0 g of O₂ reacts according to 2H₂ + O₂ → 2H₂O until one reactant is used up. What mass of water forms? (molar masses: H₂ 2.0 g/mol, O₂ 32.0 g/mol, H₂O 18.0 g/mol)

Accepted Answer

18.0 g

Answer

36.0 g

Answer

20.0 g

Answer

9.0 g

Answer

72.0 g

Question 19

On the phase diagram of water, the line between the solid and liquid regions slopes slightly to the left (it has a negative slope). What does this mean?

Accepted Answer

Raising the pressure on ice held just below 0 °C can melt it, because liquid water is denser than ice.

Answer

Raising the pressure always turns liquid water into ice.

Answer

Ice is denser than liquid water.

Answer

Water has no triple point.

Answer

Water's melting point rises as the pressure increases.

Question 20

How many protons, neutrons and electrons are in the ion ⁵⁶Fe³⁺? (The atomic number of iron is 26.)

Accepted Answer

26 protons, 30 neutrons, 23 electrons

Answer

26 protons, 30 neutrons, 29 electrons

Answer

26 protons, 56 neutrons, 23 electrons

Answer

30 protons, 26 neutrons, 23 electrons

Answer

26 protons, 30 neutrons, 26 electrons

Question 21

The rate law for a reaction is rate = k[A]²[B]. If [A] is cut in half and [B] is doubled, what happens to the rate?

Accepted Answer

It is halved.

Answer

It stays the same.

Answer

It doubles.

Answer

It becomes one-fourth as large.

Answer

It becomes four times as large.

Question 22

In the reaction BF₃ + NH₃ → F₃B–NH₃, what is the role of BF₃?

Accepted Answer

Lewis acid, because it accepts an electron pair

Answer

Lewis base, because it donates an electron pair

Answer

Brønsted–Lowry acid, because it donates a proton

Answer

Brønsted–Lowry base, because it accepts a proton

Answer

Reducing agent, because it loses electrons

Question 23

How many unpaired electrons does a ground-state iron atom (Fe, atomic number 26) have?

Accepted Answer

4

Answer

2

Answer

6

Answer

0

Answer

3

Question 24

What is the molecular geometry of chlorine trifluoride, ClF₃?

Accepted Answer

T-shaped

Answer

Trigonal planar

Answer

Trigonal pyramidal

Answer

Seesaw

Answer

Trigonal bipyramidal

Question 25

Each species below has 10 electrons. Which one has the largest radius?

Accepted Answer

O²⁻

Answer

F⁻

Answer

Ne

Answer

Na⁺

Answer

Mg²⁺

Free CLEP Chemistry Practice Test (2026)

Practice questions

Your score

By topic

Every question, with the explanation

What the CLEP Chemistry exam covers

Sources

Not sure where to start?