Chapter 4

Household ammonia used for cleaning contains about \(10 \mathrm{~g}\) (two significant figures) of \(\mathrm{NH}_{3}\) in \(100 \mathrm{~mL}\) (two significant figures) of solution. What is the molarity of the \(\mathrm{NH}_{3}\) in solution?

The average adult has about \(16 \mathrm{~g}\) of sodium ions in her blood. Assuming a total blood volume of \(5.0 \mathrm{~L}\), what is the molarity of \(\mathrm{Na}^{+}\) ions in blood?

What is the molarity of each ion present in aqueous solutions prepared by dissolving \(20.00 \mathrm{~g}\) of the following compounds in water to make 4.50 L of solution? (a) cobalt(III) chloride (b) nickel(III) sulfate (c) sodium permanganate (d) iron(II) bromide

What is the molarity of each ion present in aqueous solutions prepared by dissolving \(15.0 \mathrm{~g}\) of the following compounds in water to make \(655 \mathrm{~mL}\) of solution? (a) scandium(III) iodide (b) sodium carbonate (c) magnesium phosphate (d) potassium oxide

How would you prepare from the solid and pure water (a) \(0.400 \mathrm{~L}\) of \(0.155 \mathrm{M} \mathrm{Sr}(\mathrm{OH})_{2} ?\) (b) \(1.75 \mathrm{~L}\) of \(0.333 \mathrm{M}\left(\mathrm{NH}_{4}\right)_{2} \mathrm{CO}_{3} ?\)

Starting with the solid and adding water, how would you prepare \(2.00 \mathrm{~L}\) of \(0.685 \mathrm{M}\) (a) \(\mathrm{Ni}\left(\mathrm{NO}_{3}\right)_{2} ?\) (b) \(\mathrm{CuCl}_{2}\) ? (c) \(\mathrm{C}_{6} \mathrm{H}_{8} \mathrm{O}_{6}(\) vitamin \(\mathrm{C})\) ?

You are asked to prepare a \(0.8500 \mathrm{M}\) solution of aluminum nitrate. You find that you have only \(50.00 \mathrm{~g}\) of the solid. (a) What is the maximum volume of solution that you can prepare? (b) How many milliliters of this prepared solution are required to furnish \(0.5000\) mol of aluminum nitrate to a reaction? (c) If \(2.500 \mathrm{~L}\) of the prepared solution is required, how much more aluminum nitrate would you need? (d) Fifty milliliters of a \(0.450 M\) solution of aluminum nitrate is needed. How would you prepare the required solution from the solution prepared in (a)?

A reagent bottle is labeled \(0.450 \mathrm{M} \mathrm{K}_{2} \mathrm{CO}_{3}\). (a) How many moles of \(\mathrm{K}_{2} \mathrm{CO}_{3}\) are present in \(45.6 \mathrm{~mL}\) of this solution? (b) How many milliliters of this solution are required to furnish \(0.800 \mathrm{~mol}\) of \(\mathrm{K}_{2} \mathrm{CO}_{3} ?\) (c) Assuming no volume change, how many grams of \(\mathrm{K}_{2} \mathrm{CO}_{3}\) do you need to add to \(2.00 \mathrm{~L}\) of this solution to obtain a \(1.000 \mathrm{M}\) solution of \(\mathrm{K}_{2} \mathrm{CO}_{3} ?\) (d) If \(50.0 \mathrm{~mL}\) of this solution is added to enough water to make \(125 \mathrm{~mL}\) of solution, what is the molarity of the diluted solution?

Itwenty-five \(\mathrm{mL}\) of a \(0.388 \mathrm{M}\) solution of \(\mathrm{Na}_{2} \mathrm{SO}_{4}\) is mixed with \(35.3 \mathrm{~mL}\) of \(0.229 \mathrm{M} \mathrm{Na}_{2} \mathrm{SO}_{4}\). What is the molarity of the resulting solution? Assume that the volumes are additive.

Write the formulas of the following compounds and decide which are soluble in water. (a) sodium sulfate (b) iron(III) nitrate (c) silver chloride (d) chromium(III) hydroxide

Describe how you would prepare (a) cadmium(II) carbonate from a solution of cadmium(II) nitrate. (b) copper(II) hydroxide from a solution of sodium hydroxide. (c) magnesium carbonate from a solution of magnesium chloride.

Name the reagent, if any, that you would add to a solution of cobalt(III) chloride to precipitate (a) cobalt(III) phosphate. (b) cobalt(III) carbonate. (c) cobalt(III) hydroxide.

Write net ionic equations for the formation of (a) a precipitate when solutions of magnesium nitrate and potassium hydroxide are mixed. (b) two different precipitates when solutions of silver(I) sulfate and barium chloride are mixed.

Write net ionic equations to explain the formation of (a) a white precipitate when solutions of calcium sulfate and sodium carbonate are mixed. (b) two different precipitates formed when solutions of iron(III) sulfate and barium hydroxide are mixed.

Decide whether a precipitate will form when the following solutions are mixed. If a precipitate forms, write a net ionic equation for the reaction. (a) potassium nitrate and magnesium sulfate (b) silver nitrate and potassium carbonate (c) ammonium carbonate and cobalt(III) chloride (d) sodium phosphate and barium hydroxide (e) barium nitrate and potassium hydroxide

Write a net ionic equation for any precipitation reaction that occurs when \(0.1 \mathrm{M}\) solutions of the following are mixed. (a) zinc nitrate and nickel(II) chloride (b) potassium phosphate and calcium nitrate (c) sodium hydroxide and zinc nitrate (d) iron(III) nitrate and barium hydroxide

What volume of \(0.2500 \mathrm{M}\) cobalt(III) sulfate is required to react completely with (a) \(25.00 \mathrm{~mL}\) of \(0.0315 \mathrm{M}\) calcium hydroxide? (b) \(5.00 \mathrm{~g}\) of sodium carbonate? (c) \(12.50 \mathrm{~mL}\) of \(0.1249 M\) potassium phosphate?

What volume of \(0.4163 M\) barium chloride will react completely with (a) \(12.45 \mathrm{~mL}\) of \(1.732 \mathrm{M}\) sulfuric acid? (b) \(15.00 \mathrm{~g}\) of ammonium phosphate? (c) \(35.15 \mathrm{~mL}\) of \(1.28 \mathrm{M}\) potassium carbonate?

I A \(50.00-\mathrm{mL}\) sample of \(0.0250 \mathrm{M}\) silver nitrate is mixed with \(0.0400 \mathrm{M}\) chromium(III) chloride. (a) What is the minimum volume of chromium(III) chloride required to completely precipitate silver chloride? (b) How many grams of silver chloride are produced from (a)?

Aluminum ions react with carbonate ions to form an insoluble compound, aluminum carbonate. (a) Write the net ionic equation for this reaction. (b) What is the molarity of a solution of aluminum chloride if \(30.0 \mathrm{~mL}\) is required to react with \(35.5 \mathrm{~mL}\) of \(0.137 \mathrm{M}\) sodium carbonate? (c) How many grams of aluminum carbonate are formed in (b)?

When \(\mathrm{Na}_{3} \mathrm{PO}_{4}\) and \(\mathrm{Ca}\left(\mathrm{NO}_{3}\right)_{2}\) are combined, the following reaction occurs: $$ 2 \mathrm{PO}_{4}{\underline{\phantom{xx}}}^{3-}(a q)+3 \mathrm{Ca}^{2+}(a q) \longrightarrow \mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}(s) $$ How many grams of \(\mathrm{Ca}_{3}\left(\mathrm{PO}_{4}\right)_{2}(s)(\mathrm{MM}=310.18 \mathrm{~g} / \mathrm{mol})\) are obtained when \(15.00 \mathrm{~mL}\) of \(0.1386 \mathrm{M} \mathrm{Na}_{3} \mathrm{PO}_{4}\) are mixed with \(20.00 \mathrm{~mL}\) of \(0.2118 \mathrm{M}\) \(\mathrm{Ca}\left(\mathrm{NO}_{3}\right)_{2} ?\)

When solutions of aluminum sulfate and sodium hydroxide are mixed, a white gelatinous precipitate forms. (a) Write a balanced net ionic equation for the reaction. (b) What is the mass of the precipitate when \(2.76 \mathrm{~g}\) of aluminum sulfate in \(125 \mathrm{~mL}\) of solution is combined with \(85.0 \mathrm{~mL}\) of \(0.2500 \mathrm{M} \mathrm{NaOH}\) ? (c) What is the molarity of the ion in excess? (Ignore spectator ions and assume that volumes are additive.)

I Classify the following compounds as acids or bases, weak or strong. (a) perchloric acid (b) cesium hydroxide (c) carbonic acid, \(\mathrm{H}_{2} \mathrm{CO}_{3}\) (d) ethylamine, \(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{NH}_{2}\)

For an acid-base reaction, what is the reacting species, that is, the ion or molecule that appears in the chemical equation, in the following acids? (a) perchloric acid (b) hydriodic acid (c) nitrous acid (d) nitric acid (e) lactic acid \(\left(\mathrm{HC}_{3} \mathrm{H}_{5} \mathrm{O}_{3}\right)\)

For an acid-base reaction, what is the reacting species (the ion or molecule that appears in the chemical equation) in the following bases? (a) barium hydroxide (b) trimethylamine \(\left(\mathrm{CH}_{3}\right)_{3} \mathrm{~N}\) (c) aniline, \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}\) (d) sodium hydroxide

Write a balanced net ionic equation for each of the following acidbase reactions in water. (a) nitrous acid and barium hydroxide (b) potassium hydroxide and hydrofluoric acid (c) aniline \(\left(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}\right)\) and perchloric acid

Write a balanced net ionic equation for each of the following acid-base reactions in water. (a) acetic acid \(\left(\mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\right)\) with strontium hydroxide (b) diethylamine, \(\left(\mathrm{C}_{2} \mathrm{H}_{5}\right)_{2} \mathrm{NH}\), with sulfuric acid (c) aqueous hydrogen cyanide (HCN) with sodium hydroxide

Consider the following generic equation: $$ \mathrm{H}^{+}(a q)+\mathrm{B}^{-}(a q) \longrightarrow \mathrm{HB}(a q) $$ For which of the following pairs would this be the correct prototype equation for the acid-base reaction in solution? If it is not correct, write the proper equation for the acid-base reaction between the pair. (a) nitric acid and calcium hydroxide (b) hydrochloric acid and \(\mathrm{CH}_{3} \mathrm{NH}_{2}\) (c) hydrobromic acid and aqueous ammonia (d) perchloric acid and barium hydroxide (e) sodium hydroxide and nitrous acid

Consider the following generic equation $$ \mathrm{OH}^{-}(a q)+\mathrm{HB}(a q) \longrightarrow \mathrm{B}^{-}(a q)+\mathrm{H}_{2} \mathrm{O} $$ For which of the following pairs would this be the correct prototype equation for the acid-base reaction in solution? If it is not correct, write the proper equation for the acid-base reaction between the pair. (a) hydrochloric acid and pyridine, \(\mathrm{C}_{5} \mathrm{H}_{5} \mathrm{~N}\) (b) sulfuric acid and rubidium hydroxide (c) potassium hydroxide and hydrofluoric acid (d) ammonia and hydriodic acid (e) strontium hydroxide and hydrocyanic acid

What volume of \(0.285 \mathrm{M}\) strontium hydroxide is required to neutralize \(25.00 \mathrm{~mL}\) of \(0.275 \mathrm{M}\) hydrofluoric acid (HF)?

What is the volume of \(1.222 \mathrm{M}\) sodium hydroxide required to react with (a) \(32.5 \mathrm{~mL}\) of \(0.569 \mathrm{M}\) sulfurous acid? (One mole of sulfurous acid reacts with two moles of hydroxide ion.) (b) \(5.00 \mathrm{~g}\) of oxalic acid \(\left(\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4}\right)\) ? (One mole of oxalic acid reacts with two moles of hydroxide ion.) (c) \(15.0 \mathrm{~g}\) of concentrated acetic acid \(\left(\mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\right)\) that is \(88 \%\) by mass pure?

What is the volume of \(0.885 M\) hydrochloric acid required to react with (a) \(25.00 \mathrm{~mL}\) of \(0.288 \mathrm{M}\) aqueous ammonia? (b) \(10.00 \mathrm{~g}\) of sodium hydroxide? (c) \(25.0 \mathrm{~mL}\) of a solution \(\left(d=0.928 \mathrm{~g} / \mathrm{cm}^{3}\right)\) containing \(10.0 \%\) by mass of methylamine \(\left(\mathrm{CH}_{3} \mathrm{NH}_{2}\right) ?\)

Analysis shows that a sample of \(\mathrm{H}_{2} \mathrm{X}\) (MM \(=100.0 \mathrm{~g} / \mathrm{mol}\) ) reacts completely with \(330.0 \mathrm{~mL}\) of \(0.2000 \mathrm{M} \mathrm{KOH}\). $$ \mathrm{H}_{2} \mathrm{X}(a q)+2 \mathrm{OH}^{-}(a q) \longrightarrow \mathrm{X}^{-}(a q)+2 \mathrm{H}_{2} \mathrm{O} $$ What is the volume of the sample? (Density of \(\mathrm{H}_{2} \mathrm{X}=1.200 \mathrm{~g} / \mathrm{mL}\).)

Analysis of an unknown acid shows that \(24.55 \mathrm{~mL}\) of \(0.128 \mathrm{M} \mathrm{NaOH}\) are required to react completely with \(0.566 \mathrm{~g}\) of the acid. The equation for. the reaction is $$ \mathrm{HB}(a q)+\mathrm{OH}^{-}(a q) \longrightarrow \mathrm{H}_{2} \mathrm{O}+\mathrm{B}^{-}(a q) $$ What is the molar mass of the acid?

A lead storage battery needs sulfuric acid to function. The recommended minimum concentration of sulfuric acid for maximum effectivity is about \(4.8\) M. A 10.0-mL sample of battery acid requires \(66.52\) mL of \(1.325 M\) KOH for its complete neutralization. Does the concentration of battery acid satisfy the minimum requirement? (Note: Two \(\mathrm{H}^{+}\) ions are produced for every mole of \(\mathrm{H}_{2} \mathrm{SO}_{44}\).)

For a product to be called "vinegar," it must contain at least \(5.0 \%\) acetic acid, \(\mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\), by mass. A \(10.00-\mathrm{g}\) sample of a "raspberry vinegar" is titrated with \(0.1250 \mathrm{M} \mathrm{Ba}(\mathrm{OH})_{2}\) and required \(37.50 \mathrm{~mL}\) for complete neutralization. Can the product be called a "vinegar"?

The percentage of sodium hydrogen carbonate, \(\mathrm{NaHCO}_{3}\), in a powder for stomach upsets is found by titrating with \(0.275 M\) hydrochloric acid. If \(15.5 \mathrm{~mL}\) of hydrochloric acid is required to react with \(0.500 \mathrm{~g}\) of the sample, what is the percentage of sodium hydrogen carbonate in the sample? The balanced equation for the reaction that takes place is $$ \mathrm{NaHCO}_{3}(s)+\mathrm{H}^{+}(a q) \longrightarrow \mathrm{Na}^{+}(a q)+\mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O} $$

A capsule of vitamin \(\mathrm{C}\), a weak acid, is analyzed by titrating it with \(0.425 M\) sodium hydroxide. It is found that \(6.20 \mathrm{~mL}\) of base is required to react with a capsule weighing \(0.628 \mathrm{~g}\). What is the percentage of vitamin \(\mathrm{C}\) \(\left(\mathrm{C}_{6} \mathrm{H}_{8} \mathrm{O}_{6}\right)\) in the capsule? (One mole of vitamin \(\mathrm{C}\) reacts with one mole of hydroxide ion.)

An artificial fruit beverage contains \(12.0 \mathrm{~g}\) of tartaric acid, \(\mathrm{H}_{2} \mathrm{C}_{4} \mathrm{H}_{4} \mathrm{O}_{6}\) to achieve tartness. It is titrated with a basic solution that has a density of \(1.045 \mathrm{~g} / \mathrm{cm}^{3}\) and contains \(5.00\) mass percent \(\mathrm{KOH}\). What volume of the basic solution is required? (One mole of tartaric acid reacts with two moles of hydroxide ion.)

Lactic acid, \(\mathrm{C}_{3} \mathrm{H}_{6} \mathrm{O}_{3}\), is the acid present in sour milk. A \(0.100-\mathrm{g}\) sample of pure lactic acid requires \(12.95 \mathrm{~mL}\) of \(0.0857 M\) sodium hydroxide for complete reaction. How many moles of hydroxide ion are required to neutralize one mole of lactic acid?

Assign oxidation numbers to each element in (a) nitrogen oxide (b) ammonia (c) potassium peroxide (d) chlorate ion \(\left(\mathrm{ClO}_{3}^{-}\right)\)

Assign oxidation numbers to each element in (a) methane (b) sulfurous acid (c) sodium oxide (d) the dihydrogen phosphate ion \(\left(\mathrm{H}_{2} \mathrm{PO}_{4}^{-}\right)\)

Assign oxidation numbers to each element in (a) \(\mathrm{P}_{2} \mathrm{O}_{5}\) (b) \(\mathrm{NH}_{3}\) (c) \(\mathrm{CO}_{3}{\underline{\phantom{xx}}}^{2-}\) (d) \(\mathrm{S}_{2} \mathrm{O}_{3}^{2-}\) (e) \(\mathrm{N}_{2} \mathrm{H}_{4}\)

Mssign oxidation numbers to each element in (a) \(\mathrm{HIO}_{3}\) (b) \(\mathrm{NaMnO}_{4}\) (c) \(\mathrm{SnO}_{2}\) (d) NOF (e) \(\mathrm{NaO}_{2}\)

III Classify each of the following half-reactions as oxidation or reduction. (a) \(\mathrm{O}_{2}(g) \longrightarrow \mathrm{O}^{2-}(a q)\) (b) \(\mathrm{MnO}_{4}^{-}(a q) \longrightarrow \mathrm{MnO}_{2}(s)\) (c) \(\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}(a q) \longrightarrow \mathrm{Cr}^{3+}(a q)\) (d) \(\mathrm{Cl}^{-}(a q) \longrightarrow \mathrm{Cl}_{2}(g)\)

Classify each of the following half-reactions as oxidation or reduction. (a) \(\mathrm{TiO}_{2}(s) \longrightarrow \mathrm{Ti}^{3+}(a q)\) (b) \(\mathrm{Zn}^{2+}(a q) \longrightarrow \mathrm{Zn}(s)\) (c) \(\mathrm{NH}_{4}{\underline{\phantom{xx}}}^{+}(a q) \longrightarrow \mathrm{N}_{2}(g)\) (d) \(\mathrm{CH}_{3} \mathrm{OH}(a q) \longrightarrow \mathrm{CH}_{2} \mathrm{O}(a q)\)

Wlassify each of the following half-equations as oxidation or reduction and balance. (a) (acidic) \(\quad \mathrm{Mn}^{2+}(a q) \longrightarrow \mathrm{MnO}_{4}^{-}(a q)\) (b) (basic) \(\quad \mathrm{CrO}_{4}^{2-}(a q) \longrightarrow \mathrm{Cr}^{3+}(a q)\) (c) (basic) \(\quad \mathrm{PbO}_{2}(s) \longrightarrow \mathrm{Pb}^{2+}(a q)\) (d) (acidic) \(\quad \mathrm{ClO}_{2}^{-}(a q) \longrightarrow \mathrm{ClO}^{-}(a q)\)

Classify each of the following half-equations as oxidation or reduction and balance. (a) (basic) \(\quad \mathrm{ClO}^{-}(a q) \longrightarrow \mathrm{Cl}^{-}(a q)\) (b) (acidic) \(\quad \mathrm{NO}_{3}^{-}(a q) \longrightarrow \mathrm{NO}(g)\) (c) (basic) \(\quad \mathrm{Ni}^{2+}(a q) \longrightarrow \mathrm{Ni}_{2} \mathrm{O}_{3}(s)\) (d) (acidic) \(\quad \mathrm{Mn}^{2+}(a q) \longrightarrow \mathrm{MnO}_{2}(s)\)

For each unbalanced equation given below- write unbalanced half-reactions. identify the species oxidized and the species reduced. Id identify the oxidizing and reducing agents. (a) \(\mathrm{Ag}(s)+\mathrm{NO}_{3}^{-}(a q) \longrightarrow \mathrm{Ag}^{+}(a q)+\mathrm{NO}(g)\) (b) \(\mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(l) \longrightarrow \mathrm{C}_{2} \mathrm{H}_{4}(g)+\mathrm{O}_{2}(g)\)

Write balanced equations for the following reactions in acid solution. (a) \(\mathrm{P}_{4}(s)+\mathrm{Cl}^{-}(a q) \longrightarrow \mathrm{PH}_{3}(g)+\mathrm{Cl}_{2}(g)\) (b) \(\mathrm{MnO}_{4}^{-}(a q)+\mathrm{NO}_{2}^{-}(a q) \longrightarrow \mathrm{Mn}^{2+}(a q)+\mathrm{NO}_{3}^{-}(a q)\) (c) \(\mathrm{HBrO}_{3}(a q)+\mathrm{Bi}(s) \longrightarrow \mathrm{HBrO}_{2}(a q)+\mathrm{Bi}_{2} \mathrm{O}_{3}(s)\) (d) \(\mathrm{CrO}_{4}^{2-}(a q)+\mathrm{SO}_{3}^{2-}(a q) \longrightarrow \mathrm{Cr}^{3+}(a q)+\mathrm{SO}_{4}^{2-}(a q)\)