Q: Which of the following best describes the definition of molarity ($M$)?

$M = \dfrac{\text{amount of solute (in mol)}}{\text{volume of solution (in L)}}$

Question 1

A solution is prepared by dissolving 25.5 g of KBr in enough water to make 1.75 L of solution. What is the molarity of the solution? (Molar mass of KBr = 119.00 g/mol)

Accepted Answer

$0.122\,\mathrm{M}$

Question 2

Which of the following best describes the definition of molarity ($M$)?

Accepted Answer

$M = \dfrac{	ext{amount of solute (in mol)}}{	ext{volume of solution (in L)}}$

Question 3

How many liters of a $0.125\,\mathrm{M}$ NaOH solution are required to contain $0.255$ mol NaOH?

Accepted Answer

$2.04\,\mathrm{L}$

Question 4

A student wants to prepare $250.0\,\mathrm{mL}$ of a $1.50\,\mathrm{M}$ KBr solution. What mass of KBr (in grams) is required? (Molar mass of KBr = $119.00\,\mathrm{g/mol}$)

Accepted Answer

$44.6\,\mathrm{g}$

Question 5

What volume (in L) should you dilute $0.200\,\mathrm{L}$ of a $15.0\,\mathrm{M}$ NaOH solution to obtain a $3.00\,\mathrm{M}$ NaOH solution?

Accepted Answer

$1.00\,\mathrm{L}$

Question 6

Which of the following compounds is insoluble in water?

Accepted Answer

PbCl$_2$

Question 7

What is the balanced molecular equation for the precipitation reaction when solutions of potassium carbonate and nickel(II) chloride are mixed?

Accepted Answer

$K_2CO_3(aq) + NiCl_2(aq) \rightarrow NiCO_3(s) + 2KCl(aq)$

Question 8

Which of the following is the net ionic equation for the reaction between aqueous acetic acid ($HC_2H_3O_2$) and potassium hydroxide ($KOH$)?

Accepted Answer

$HC_2H_3O_2(aq) + OH^-(aq) \rightarrow H_2O(l) + C_2H_3O_2^-(aq)$

Question 9

A titration of $10.00\,\mathrm{mL}$ of HCl solution of unknown concentration requires $12.54\,\mathrm{mL}$ of $0.100\,\mathrm{M}$ NaOH solution to reach the equivalence point. What is the concentration of the unknown HCl solution?

Accepted Answer

$0.125\,\mathrm{M}$

Question 10

Which of the following is the correct molecular equation for the gas-evolution reaction when aqueous nitric acid reacts with sodium carbonate?

Accepted Answer

$2HNO_3(aq) + Na_2CO_3(aq) \rightarrow H_2O(l) + CO_2(g) + 2NaNO_3(aq)$

Question 11

Assign the oxidation state to sulfur in $SO_4^{2-}$.

Accepted Answer

$+6$

Question 12

In the reaction $Mg(s) + 2H_2O(l) \rightarrow Mg(OH)_2(aq) + H_2(g)$, which element is oxidized and which is reduced?

Accepted Answer

Mg is oxidized, H is reduced

Question 13

Which of the following reactions is a redox reaction? Identify the oxidizing agent.

Accepted Answer

$2Mg(s) + O_2(g) \rightarrow 2MgO(s)$; oxidizing agent: $O_2$

Question 14

Predict whether the following redox reaction is spontaneous: $Fe(s) + Pb^{2+}(aq) \rightarrow Fe^{2+}(aq) + Pb(s)$

Accepted Answer

Spontaneous

Question 15

Which of the following is the correct net ionic equation for the neutralization of HCl with NaOH?

Accepted Answer

$H^+(aq) + OH^-(aq) \rightarrow H_2O(l)$

Question 16

A $0.150\,\mathrm{M}$ KCl solution is to react completely with $0.150\,\mathrm{L}$ of $0.175\,\mathrm{M}$ Pb(NO$_3$)$_2$ solution according to the equation $2KCl(aq) + Pb(NO_3)_2(aq) \rightarrow PbCl_2(s) + 2KNO_3(aq)$. What volume (in L) of KCl solution is required?

Accepted Answer

$0.350\,\mathrm{L}$

Question 17

Which of the following compounds is always soluble in water?

Accepted Answer

Ca(NO$_3$)$_2$

Chapter 5: Introduction to Solutions and Aqueous Reactions – Study Notes

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