Loading test…

AP Chemistry Easy practice

15 questions

Header banner

Easy practice

0 of 15 answered

~9 min left

Question 1

For the equilibrium $N_{2} (g) + 3 H_{2} (g) ⇌ 2 N H_{3} (g)$ , which expression correctly represents $K_{c}$ ?

K_{c} = \frac{[ N H _{3} ] ^{2}}{[ N _{2} ] [ H _{2} ] ^{3}}

K_{c} = \frac{[ N _{2} ] [ H _{2} ] ^{3}}{[ N H _{3} ] ^{2}}

K_{c} = \frac{[ N H _{3} ]}{[ N _{2} ] [ H _{2} ]}

K_{c} = \frac{[ N H _{3} ] ^{2}}{[ N _{2} ] ^{2} [ H _{2} ] ^{3}}

Question 2

Explain why $HF$ has a much higher boiling point ( $19.5° C$ ) than $HCl$ ( $- 85° C$ ), even though HCl has the larger molar mass.

A.HF has stronger London dispersion forces because fluorine is highly electronegative.B.HF molecules engage in hydrogen bonding, a much stronger intermolecular attraction than the dipole–dipole forces in HCl.C.The H–F bond is covalent while H–Cl is ionic.D.HF has a higher molar mass than HCl.

Question 3

When a small piece of sodium metal is added to water, bubbles form vigorously and the solution becomes basic. What type of reaction is occurring?

A.Double-displacement (metathesis) reactionB.Combustion reactionC.Single-displacement (redox) reactionD.Acid–base neutralization

Question 4

For a reaction with $K_{c} = 5.0 \times 1 0^{- 8}$ , which statement best characterizes the equilibrium?

A.At equilibrium, the mixture contains mostly products.B.At equilibrium, reactants and products are present in roughly equal amounts.C.At equilibrium, the mixture is predominantly reactants.D.The reaction does not reach equilibrium because

K_{c}

is too small.

Question 5

What is the pH of a $0.010 M$ solution of $HCl$ ?

1.0

2.0

3.0

12.0

In-content ad

Question 6

Which type of intermolecular force is present in ALL molecular substances?

A.Hydrogen bondingB.Dipole–dipole forcesC.London dispersion forcesD.Ion–dipole forces

Question 7

Which of the following is the conjugate base of $H_{2} P O_{4}^{-}$ ?

H_{3} P O_{4}

HP O_{4}^{2 -}

P O_{4}^{3 -}

H_{2} O

Question 8

A student burns $1.00 g$ of ethanol in a calorimeter containing $500 g$ of water. The temperature rises from $22.5° C$ to $35.7° C$ . What is the heat absorbed by the water? ( $c_{water} = 4.18 J/ (g \cdot °C)$ )

2.76 kJ

27.6 kJ

55.2 kJ

0.276 kJ

Question 9

A buffer solution is prepared containing $0.200 M$ acetic acid ( $C H_{3} COOH$ , $p K_{a} = 4.74$ ) and $0.200 M$ sodium acetate ( $C H_{3} COONa$ ). What is the pH of this buffer?

2.87

4.74

7.00

9.26

Question 10

Which of the following molecules is polar?

B F_{3}

CC l_{4}

C O_{2}

H_{2} S

In-content ad

Question 11

What is the difference between heat ( $q$ ) and temperature ( $T$ )?

A.Heat and temperature are the same thing measured in different units.B.Temperature measures the average kinetic energy of particles; heat is the energy transferred due to a temperature difference.C.Heat is a property of objects; temperature is a form of energy.D.A large object always has more heat than a small object at the same temperature.

Question 12

Which of the following correctly orders the elements by increasing first ionization energy?

$Li, Na, K$

Li < Na < K

K < Na < Li

Na < K < Li

Li < K < Na

Question 13

For a spontaneous process at constant temperature and pressure, which condition must be met?

Δ H < 0

onlyB.

Δ S > 0

onlyC.

Δ G = Δ H - T Δ S < 0

Δ H < 0

and

Δ S < 0

simultaneously

Question 14

When a hot metal block is placed in cool water and the system reaches thermal equilibrium, which statement is correct?

A.Heat flows from the water to the metal until their temperatures equalize.B.The heat lost by the metal equals the heat gained by the water (assuming no heat loss to surroundings).C.The metal loses more heat than the water gains because metal is denser.D.The temperature changes of the metal and water must be equal.

Question 15

Assign oxidation numbers and identify the element that is oxidized in the following reaction:

$Zn (s) + 2 HCl (aq) \to ZnC l_{2} (aq) + H_{2} (g)$

A.H is oxidized (changes from

+ 1

0

).B.Zn is oxidized (changes from

0

+ 2

).C.Cl is oxidized (stays at

- 1

).D.Zn is reduced (changes from

0

+ 2

AP Chemistry Easy practice — Free with Answer Explanations | Test Practice Hub