Question 1

Which of the following compounds is a strong electrolyte when dissolved in water?

Accepted Answer

NaCl

Question 2

A chemical equilibrium exists when:

Accepted Answer

The rate of the forward reaction equals the rate of the reverse reaction.

Question 3

A gas is transferred from a 3.83 atm pressure in a 1.00 L container at 26.0 $^\circ$C to a 10.0 L container at 65.0 $^\circ$C. What is the new pressure, assuming the amount of gas is constant?

Accepted Answer

$0.536$ atm

Question 4

Refer to the energy diagram below. Which statement is true regarding the activation energy of the forward reaction?

Accepted Answer

The activation energy of the forward reaction is $X$.

Question 5

Which of the following is NOT a property predicted based on the Kinetic Molecular Theory?

Accepted Answer

It explains why the volume of a gas decreases as temperature increases.

Question 6

Chromium metal and oxygen gas react to form chromium(III) oxide according to the following balanced chemical equation:

$4	ext{Cr}(s) + 3	ext{O}_2(g) ightarrow 2	ext{Cr}_2	ext{O}_3(s)$

If 50.0 moles of Cr is reacted with 20.0 moles of O$_2$, which reactant is the limiting reactant and how many moles of Cr$_2$O$_3$ form?

Accepted Answer

O$_2$ is the limiting reactant forming 13.3 moles of Cr$_2$O$_3$

Question 7

What volume (mL) of a 10.5 M solution of sodium hydroxide (NaOH) must be diluted to prepare a 200. mL solution of 1.75 M sodium hydroxide?

Accepted Answer

$33.3$ mL

Question 8

Based on solubility guidelines, which of the following cations would form a precipitate in water with phosphate (PO$_4^{3-}$) anion but NOT with chloride (Cl$^-$) anion?

Accepted Answer

Fe$^{3+}$

Question 9

Potassium nitrate has a solubility of 32 g of KNO$_3$ in 100 g of H$_2$O at 20 $^\circ$C. Which of the following statements is true?

Accepted Answer

At 20 $^\circ$C, 32 g of KNO$_3$ dissolved in 100 g of H$_2$O will form a saturated solution.

Question 10

What is the pressure (in atm) of 0.133 moles of NH$_3$ gas found in a 7.50 L container at a temperature of $-40.0$ $^\circ$C?

Accepted Answer

$0.263$ atm

Question 11

If the pressure of a constant amount of gas at constant temperature is increased by threefold, what happens to its volume?

Accepted Answer

The volume decreases by one-third.

Question 12

How many liters of CO$_2$ gas are needed to react completely with 56.0 L of CH$_4$ (g) at STP to produce CO$_2$ (g) and H$_2$O (g)?

$CH_4(g) + 2O_2(g) \rightarrow CO_2(g) + 2H_2O(g)$

Accepted Answer

$56.0$ L

Question 13

What mass of NH$_3$ is needed to completely react with 8.00 moles of O$_2$ (g) based on the reaction below?

$4NH_3(g) + 3O_2(g) \rightarrow 2N_2(g) + 6H_2O(g)$

Accepted Answer

$10.7$ moles NH$_3$

Question 14

Consider the following reaction:

$2H_2O_2(aq) \rightarrow 2H_2O(l) + O_2(g)$

The heat of the reaction is $-196$ kJ. Which of the following statements is true about this reaction?

Accepted Answer

The reaction is exothermic and heat is released by this reaction.

Question 15

A gas mixture contains O$_2$ and N$_2$. If O$_2$ has a partial pressure of 0.74 atm and N$_2$ has a partial pressure of 0.88 atm, what is the total pressure of this mixture in atm?

Accepted Answer

$1.62$ atm

Question 16

Which of the following aqueous solutions would be expected to have the highest osmotic pressure?

Accepted Answer

1 M CaCl$_2$

Question 17

Which pair of compounds will form a solution?

Accepted Answer

C$_2$H$_5$OH and hexane (C$_6$H$_{14}$)

Question 18

For the reaction $2H_2S(g) \rightarrow 2H_2(g) + S_2(g)$, what is the equilibrium expression?

Accepted Answer

$K = \dfrac{[H_2]^2[S_2]}{[H_2S]^2}$

Question 19

Based on the concentration plot below, what is the best estimate of the time that equilibrium is established?

Accepted Answer

8 hrs

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