Chapter 6

Write the balanced formula, complete ionic, and net ionic equations for each of the following acid-base reactions. a. \(\mathrm{HClO}_{4}(a q)+\mathrm{Mg}(\mathrm{OH})_{2}(s) \rightarrow\) b. \(\mathrm{HCN}(a q)+\mathrm{NaOH}(a q) \rightarrow\) c. \(\mathrm{HCl}(a q)+\mathrm{NaOH}(a q) \rightarrow\)

Write the balanced formula, complete ionic, and net ionic equations for each of the following acid-base reactions. a. \(\mathrm{HNO}_{3}(a q)+\mathrm{Al}(\mathrm{OH})_{3}(s) \rightarrow\) b. \(\mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}(a q)+\mathrm{KOH}(a q) \rightarrow\) c. \(\mathrm{Ca}(\mathrm{OH})_{2}(a q)+\mathrm{HCl}(a q) \rightarrow\)

Write the balanced formula equation for the acid-base reactions that occur when the following are mixed. a. potassium hydroxide (aqueous) and nitric acid b. barium hydroxide (aqueous) and hydrochloric acid c. perchloric acid \(\left[\mathrm{HClO}_{4}(a q)\right]\) and solid iron(III) hydroxide d. solid silver hydroxide and hydrobromic acid e. aqueous strontium hydroxide and hydroiodic acid

What acid and what base would react in aqueous solution so that the following salts appear as products in the formula equation? Write the balanced formula equation for each reaction. a. potassium perchlorate b. cesium nitrate c. calcium iodide

What volume of each of the following acids will react completely with \(50.00 \mathrm{mL}\) of \(0.200 \mathrm{M} \mathrm{NaOH} ?\) a. \(0.100 M\) HCl b. \(0.150 M\) HNO \(_{3}\) c. \(0.200 \mathrm{M} \mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\) (1 acidic hydrogen)

What volume of each of the following bases will react completely with \(25.00 \mathrm{mL}\) of \(0.200 \mathrm{M}\) HCl? a. \(0.100 M\) NaOH c. \(0.250 M\) KOH b. \(0.0500 M \operatorname{Sr}(O H)_{2}\)

Hydrochloric acid (75.0 mL of 0.250 \(M\) ) is added to 225.0 mL of 0.0550 \(M\) Ba(OH) \(_{2}\) solution. What is the concentration of the excess \(\mathrm{H}^{+}\) or \(\mathrm{OH}^{-}\) ions left in this solution?

A student mixes four reagents together, thinking that the solutions will neutralize each other. The solutions mixed together are 50.0 mL of 0.100 \(M\) hydrochloric acid, \(100.0 \mathrm{mL}\) of \(0.200 \mathrm{M}\) of nitric acid, \(500.0 \mathrm{mL}\) of \(0.0100 \mathrm{M}\) calcium hydroxide, and 200.0 mL. of 0.100 \(M\) rubidium hydroxide. Did the acids and bases exactly neutralize each other? If not, calculate the concentration of excess \(\mathrm{H}^{+}\) or \(\mathrm{OH}^{-}\) ions left in solution.

A \(25.00-\mathrm{mL}\) sample of hydrochloric acid solution requires \(24.16 \mathrm{mL}\) of \(0.106 \mathrm{M}\) sodium hydroxide for complete neutralization. What is the concentration of the original hydrochloric acid solution?

A 10.00 -mL sample of vinegar, an aqueous solution of acetic acid \(\left(\mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2}\right),\) is titrated with \(0.5062 \mathrm{M} \mathrm{NaOH},\) and \(16.58 \mathrm{mL}\) is required to reach the equivalence point. a. What is the molarity of the acetic acid? b. If the density of the vinegar is \(1.006 \mathrm{g} / \mathrm{cm}^{3},\) what is the mass percent of acetic acid in the vinegar?

What volume of \(0.0200 \mathrm{M}\) calcium hydroxide is required to neutralize \(35.00 \mathrm{mL}\) of \(0.0500 \mathrm{M}\) nitric acid?

A 30.0 -mL. sample of an unknown strong base is neutralized after the addition of \(12.0 \mathrm{mL}\) of a \(0.150 \mathrm{M} \mathrm{HNO}_{3}\) solution. If the unknown base concentration is 0.0300 \(M,\) give some possible identities for the unknown base.

A student titrates an unknown amount of potassium hydrogen phthalate \(\left(\mathrm{KHC}_{8} \mathrm{H}_{4} \mathrm{O}_{4},\) often abbreviated KHP) with \right. \(20.46 \mathrm{mL}\) of a \(0.1000-M \mathrm{NaOH}\) solution. KHP (molar mass \(=\) \(204.22 \mathrm{g} / \mathrm{mol}\) ) has one acidic hydrogen. What mass of KHP was titrated (reacted completely) by the sodium hydroxide solution?

The concentration of a certain sodium hydroxide solution was determined by using the solution to titrate a sample of potassium hydrogen phthalate (abbreviated as KHP). KHP is an acid with one acidic hydrogen and a molar mass of \(204.22 \mathrm{g} / \mathrm{mol}\). In the titration, \(34.67 \mathrm{mL}\) of the sodium hydroxide solution was required to react with 0.1082 g KHP. Calculate the molarity of the sodium hydroxide.

Assign oxidation states for all atoms in each of the following compounds. a. \(\mathrm{KMnO}_{4}\) f. \(\mathrm{Fe}_{3} \mathrm{O}_{4}\) b. \(\mathrm{NiO}_{2}\) g. \(\mathrm{XeOF}_{4}\) c. \(\mathrm{Na}_{4} \mathrm{Fe}(\mathrm{OH})_{6}\) h. \(\mathrm{SF}_{4}\) d. \(\left(\mathrm{NH}_{4}\right)_{2} \mathrm{HPO}_{4}\) i. \(\mathrm{CO}\) e. \(\mathrm{P}_{4} \mathrm{O}_{6}\) j. \(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{6}\)

Assign oxidation states for all atoms in each of the following compounds. a. \(U O_{2}^{2+}\) f. \(\mathrm{Mg}_{2} \mathrm{P}_{2} \mathrm{O}_{7}\) b. \(\mathrm{As}_{2} \mathrm{O}_{3}\) g. \(\mathrm{Na}_{2} \mathrm{S}_{2} \mathrm{O}_{3}\) c. \(\mathrm{NaBiO}_{3}\) h. \(\mathrm{Hg}_{2} \mathrm{Cl}_{2}\) d. \(\mathrm{As}_{4}\) i. \(\quad \mathrm{Ca}\left(\mathrm{NO}_{3}\right)_{2}\) e. \(\mathrm{HAsO}_{2}\)

Assign the oxidation state for nitrogen in each of the following. a. \(\mathrm{Li}_{3} \mathrm{N}\) b. \(\mathrm{NH}_{3}\) \(\mathbf{c} . \mathrm{N}_{2} \mathrm{H}_{4}\) d. NO e. \(\mathrm{N}_{2} \mathrm{O}\) \(\mathbf{f} . \mathrm{NO}_{2}\) g. \(\mathrm{NO}_{2}^{-}\) h. \(\mathrm{NO}_{3}^{-}\) \(\mathbf{i} . \quad \mathbf{N}_{2}\)

Assign oxidation numbers to all the atoms in each of the following. a. \(\operatorname{Sr} \mathrm{Cr}_{2} \mathrm{O}_{7}\) b. \(\mathrm{CuCl}_{2}\) c. \(O_{2}\) \(\mathbf{d .} \mathbf{H}_{2} \mathbf{O}_{2}\) e. \(\mathrm{MgCO}_{3}\) f. Ag g. \(\mathrm{PbSO}_{3}\) h. \(\mathrm{PbO}_{2}\) i. \(\quad \mathrm{Na}_{2} \mathrm{C}_{2} \mathrm{O}_{4}\) \(\mathbf{j} . \mathrm{CO}_{2}\) \(\mathbf{k} .\left(\mathrm{NH}_{4}\right)_{2} \mathrm{Ce}\left(\mathrm{SO}_{4}\right)_{3}\) I. \(\quad \mathrm{Cr}_{2} \mathrm{O}_{3}\)

Specify which of the following are oxidation-reduction reactions, and identify the oxidizing agent, the reducing agent, the substance being oxidized, and the substance being reduced. a. \(\mathrm{Cu}(s)+2 \mathrm{Ag}^{+}(a q) \rightarrow 2 \mathrm{Ag}(s)+\mathrm{Cu}^{2+}(a q)\) b. \(\mathrm{HCl}(g)+\mathrm{NH}_{3}(g) \rightarrow \mathrm{NH}_{4} \mathrm{Cl}(s)\) c. \(\mathrm{SiCl}_{4}(l)+2 \mathrm{H}_{2} \mathrm{O}(l) \rightarrow 4 \mathrm{HCl}(a q)+\mathrm{SiO}_{2}(s)\) d. \(\mathrm{SiCl}_{4}(l)+2 \mathrm{Mg}(s) \rightarrow 2 \mathrm{MgCl}_{2}(s)+\mathrm{Si}(s)\) e. \(\mathrm{Al}(\mathrm{OH})_{4}^{-}(a q) \rightarrow \mathrm{AlO}_{2}^{-}(a q)+2 \mathrm{H}_{2} \mathrm{O}(i)\)

Specify which of the following equations represent oxidationreduction reactions, and indicate the oxidizing agent, the reducing agent, the species being oxidized, and the species being reduced. a. \(\mathrm{CH}_{4}(g)+\mathrm{H}_{2} \mathrm{O}(g) \rightarrow \mathrm{CO}(g)+3 \mathrm{H}_{2}(g)\) b. \(2 \mathrm{AgNO}_{3}(a q)+\mathrm{Cu}(s) \rightarrow \mathrm{Cu}\left(\mathrm{NO}_{3}\right)_{2}(a q)+2 \mathrm{Ag}(s)\) c. \(\mathrm{Zn}(s)+2 \mathrm{HCl}(a q) \rightarrow \mathrm{ZnCl}_{2}(a q)+\mathrm{H}_{2}(g)\) d. \(2 \mathrm{H}^{+}(a q)+2 \mathrm{CrO}_{4}^{2-}(a q) \rightarrow \mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}(a q)+\mathrm{H}_{2} \mathrm{O}(i)\)

Consider the reaction between sodium metal and fluorine ( \(\mathbf{F}_{2}\) ) gas to form sodium fluoride. Using oxidation states, how many electrons would each sodium atom lose, and how many electrons would each fluorine atom gain? How many sodium atoms are needed to react with one fluorine molecule? Write a balanced equation for this reaction.

Consider the reaction between oxygen \(\left(\mathrm{O}_{2}\right)\) gas and magnesium metal to form magnesium oxide. Using oxidation states, how many electrons would each oxygen atom gain, and how many electrons would each magnesium atom lose? How many magnesium atoms are needed to react with one oxygen molecule? Write a balanced equation for this reaction.

Balance each of the following oxidation-reduction reactions by using the oxidation states method. a. \(\mathrm{C}_{2} \mathrm{H}_{6}(g)+\mathrm{O}_{2}(g) \rightarrow \mathrm{CO}_{2}(g)+\mathrm{H}_{2} \mathrm{O}(g)\) b. \(\mathrm{Mg}(s)+\mathrm{HCl}(a q) \rightarrow \mathrm{Mg}^{2+}(a q)+\mathrm{Cl}^{-}(a q)+\mathrm{H}_{2}(g)\) c. \(\mathrm{Co}^{3+}(a q)+\mathrm{Ni}(s) \rightarrow \mathrm{Co}^{2+}(a q)+\mathrm{Ni}^{2+}(a q)\) d. \(\mathrm{Zn}(s)+\mathrm{H}_{2} \mathrm{SO}_{4}(a q) \rightarrow \mathrm{ZnSO}_{4}(a q)+\mathrm{H}_{2}(g)\)

Balance each of the following oxidation-reduction reactions by using the oxidation states method. a. \(\mathrm{Cl}_{2}(g)+\mathrm{Al}(s) \rightarrow \mathrm{Al}^{3+}(a q)+\mathrm{Cl}^{-}(a q)\) b. \(\mathbf{O}_{2}(g)+\mathbf{H}_{2} \mathbf{O}(l)+\mathbf{P b}(s) \rightarrow \mathbf{P b}(\mathbf{O H})_{2}(s)\) c. \(\mathrm{H}^{+}(a q)+\mathrm{MnO}_{4}^{-}(a q)+\mathrm{Fe}^{2+}(a q) \rightarrow\) \(\mathrm{Mn}^{2+}(a q)+\mathrm{Fe}^{3+}(a q)+\mathrm{H}_{2} \mathrm{O}(i)\)

You wish to prepare 1 L of a \(0.02-M\) potassium iodate solution. You require that the final concentration be within \(1 \%\) of \(0.02 M\) and that the concentration must be known accurately to the fourth decimal place. How would you prepare this solution? Specify the glassware you would use, the accuracy needed for the balance, and the ranges of acceptable masses of \(\mathrm{KIO}_{3}\) that can be used.

A \(230 .\) mL sample of a \(0.275-M \mathrm{CaCl}_{2}\) solution is left on a hot plate overnight; the following morning, the solution is \(1.10 \mathrm{M}\). What volume of water evaporated from the 0.275 \(M\) \(\mathrm{CaCl}_{2}\) solution?

Using the general solubility rules given in Table \(6-1,\) name three reagents that would form precipitates with each of the following ions in aqueous solution. Write the net ionic equation for each of your suggestions. a. chloride ion d. sulfate ion b. calcium ion e. mercury(I) ion, \(\mathrm{Hg}_{2}^{2+}\) c. iron(III) ion f. silver ion

Consider a \(1.50-\mathrm{g}\) mixture of magnesium nitrate and magnesium chloride. After dissolving this mixture in water, 0.500 \(M\) silver nitrate is added dropwise until precipitate formation is complete. The mass of the white precipitate formed is 0.641 g. a. Calculate the mass percent of magnesium chloride in the mixture. b. Determine the minimum volume of silver nitrate that must have been added to ensure complete formation of the precipitate.

A mixture contains only \(\mathrm{NaCl}\) and \(\mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}\). A 1.45 -g sample of the mixture is dissolved in water and an excess of NaOH is added, producing a precipitate of \(\mathrm{Al}(\mathrm{OH})_{3}\). The precipitate is filtered, dried, and weighed. The mass of the precipitate is \(0.107 \mathrm{g} .\) What is the mass percent of \(\mathrm{Al}_{2}\left(\mathrm{SO}_{4}\right)_{3}\) in the sample?

The thallium (present as \(\mathrm{Tl}_{2} \mathrm{SO}_{4}\) ) in a \(9.486-\mathrm{g}\) pesticide sample was precipitated as thallium(I) iodide. Calculate the mass percent of \(\mathrm{Tl}_{2} \mathrm{SO}_{4}\) in the sample if \(0.1824 \mathrm{g}\) of TII was recovered.

A mixture contains only \(\mathrm{NaCl}\) and \(\mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{3} .\) A \(0.456-\mathrm{g}\) sample of the mixture is dissolved in water, and an excess of NaOH is added, producing a precipitate of \(\mathrm{Fe}(\mathrm{OH})_{3} .\) The precipitate is filtered, dried, and weighed. Its mass is 0.107 g. Calculate the following. a. the mass of iron in the sample b. the mass of \(\mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{3}\) in the sample c. the mass percent of \(\mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{3}\) in the sample

Some of the substances commonly used in stomach antacids are \(\mathrm{MgO}, \mathrm{Mg}(\mathrm{OH})_{2},\) and \(\mathrm{Al}(\mathrm{OH})_{3}\) a. Write a balanced equation for the neutralization of hydrochloric acid by each of these substances. b. Which of these substances will neutralize the greatest amount of 0.10 \(M\) HCl per gram?

Acetylsalicylic acid is the active ingredient in aspirin. It took \(35.17 \mathrm{mL}\) of \(0.5065 \mathrm{M}\) sodium hydroxide to react completely with \(3.210 \mathrm{g}\) of acetylsalicylic acid. Acetylsalicylic acid has one acidic hydrogen. What is the molar mass of acetylsalicylic acid?

When hydrochloric acid reacts with magnesium metal, hydrogen gas and aqueous magnesium chloride are produced. What volume of \(5.0 \mathrm{M}\) HCl is required to react completely with \(3.00 \mathrm{g}\) of magnesium?

A \(2.20-g\) sample of an unknown acid (empirical formula = \(\left.\mathrm{C}_{3} \mathrm{H}_{4} \mathrm{O}_{3}\right)\) is dissolved in \(1.0 \mathrm{L}\) of water. A titration required \(25.0 \mathrm{mL}\) of \(0.500 \mathrm{M} \mathrm{NaOH}\) to react completely with all the acid present. Assuming the unknown acid has one acidic proton per molecule, what is the molecular formula of the unknown acid?

Chlorisondamine chloride \(\left(\mathrm{C}_{14} \mathrm{H}_{20} \mathrm{Cl}_{6} \mathrm{N}_{2}\right)\) is a drug used in the treatment of hypertension. A \(1.28-\mathrm{g}\) sample of a medication containing the drug was treated to destroy the organic material and to release all the chlorine as chloride ion. When the filtered solution containing chloride ion was treated with an excess of silver nitrate, 0.104 g silver chloride was recovered. Calculate the mass percent of chlorisondamine chloride in the medication, assuming the drug is the only source of chloride.

Saccharin \(\left(\mathrm{C}_{7} \mathrm{H}_{5} \mathrm{NO}_{3} \mathrm{S}\right)\) is sometimes dispensed in tablet form. Ten tablets with a total mass of 0.5894 g were dissolved in water. The saccharin was oxidized to convert all the sulfur to sulfate ion, which was precipitated by adding an excess of barium chloride solution. The mass of BaSO_ obtained was \(0.5032 \mathrm{g} .\) What is the average mass of saccharin per tablet? What is the average mass percent of saccharin in the tablets?

Douglasite is a mineral with the formula \(2 \mathrm{KCl} \cdot \mathrm{FeCl}_{2} \cdot 2 \mathrm{H}_{2} \mathrm{O}\) Calculate the mass percent of douglasite in a 455.0 -mg sample if it took \(37.20 \mathrm{mL}\) of a \(0.1000-M \mathrm{AgNO}_{3}\) solution to precipitate all the \(\mathrm{Cl}^{-}\) as \(\mathrm{AgCl}\). Assume the douglasite is the only source of chloride ion.

Many oxidation-reduction reactions can be balanced by inspection. Try to balance the following reactions by inspection. In each reaction, identify the substance reduced and the substance oxidized. a. \(\mathrm{Al}(s)+\mathrm{HCl}(a q) \rightarrow \mathrm{AlCl}_{3}(a q)+\mathrm{H}_{2}(g)\) b. \(\mathrm{CH}_{4}(g)+\mathrm{S}(s) \rightarrow \mathrm{CS}_{2}(l)+\mathrm{H}_{2} \mathrm{S}(g)\) c. \(C_{3} H_{8}(g)+O_{2}(g) \rightarrow C O_{2}(g)+H_{2} O(l)\) d. \(\mathrm{Cu}(s)+\mathrm{Ag}^{+}(a q) \rightarrow \mathrm{Ag}(s)+\mathrm{Cu}^{2+}(a q)\)

The blood alcohol \(\left(\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}\right)\) level can be determined by titrating a sample of blood plasma with an acidic potassium dichromate solution, resulting in the production of \(\mathrm{Cr}^{3+}(a q)\) and carbon dioxide. The reaction can be monitored because the dichromate ion \(\left(\mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}\right)\) is orange in solution, and the \(\mathrm{Cr}^{3+}\) ion is green. The balanced equation is \(16 \mathrm{H}^{+}(a q)+2 \mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}(a q)+\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}(a q) \longrightarrow\) $$ 4 \mathrm{Cr}^{3+}(a q)+2 \mathrm{CO}_{2}(g)+11 \mathrm{H}_{2} \mathrm{O}(i) $$ This reaction is an oxidation-reduction reaction. What species is reduced, and what species is oxidized? How many electrons are transferred in the balanced equation above?

Calculate the concentration of all ions present when \(0.160 \mathrm{g}\) of \(\mathrm{MgCl}_{2}\) is dissolved in \(100.0 \mathrm{mL}\) of solution.

A solution is prepared by dissolving 0.6706 g oxalic acid \(\left(\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4}\right)\) in enough water to make \(100.0 \mathrm{mL}\) of solution. \(\mathrm{A}\) \(10.00-\mathrm{mL}\) aliquot (portion) of this solution is then diluted to a final volume of \(250.0 \mathrm{mL}\). What is the final molarity of the oxalic acid solution?

For the following chemical reactions, determine the precipitate produced when the two reactants listed below are mixed together. Indicate "none" if no precipitate will form.

What volume of 0.100 \(M\) NaOH is required to precipitate all of the nickel(II) ions from \(150.0 \mathrm{mL}\) of a \(0.249-M\) solution of \(\mathrm{Ni}\left(\mathrm{NO}_{3}\right)_{2} ?\)

A 500.0 -mL sample of \(0.200 \mathrm{M}\) sodium phosphate is mixed with \(400.0 \mathrm{mL}\) of \(0.289 M\) barium chloride. What is the mass of the solid produced?

A 450.0 -mL sample of a 0.257 - \(M\) solution of silver nitrate is mixed with \(400.0 \mathrm{mL}\) of \(0.200 \mathrm{M}\) calcium chloride. What is the concentration of \(\mathrm{Cl}^{-}\) in solution after the reaction is complete?

The zinc in a 1.343 -g sample of a foot powder was precipitated as ZnNH,PO_. Strong heating of the precipitate yielded \(0.4089 \mathrm{g} \mathrm{Zn}_{2} \mathrm{P}_{2} \mathrm{O}_{7}\). Calculate the mass percent of zinc in the sample of foot powder.

A 50.00 -mL sample of aqueous \(\mathrm{Ca}(\mathrm{OH})_{2}\) requires \(34.66 \mathrm{mL}\) of a 0.944-M nitric acid for neutralization. Calculate the concentration (molarity) of the original solution of calcium hydroxide.

When organic compounds containing sulfur are burned, sulfur dioxide is produced. The amount of \(\mathrm{SO}_{2}\) formed can be determined by the reaction with hydrogen peroxide: $$ \mathrm{H}_{2} \mathrm{O}_{2}(a q)+\mathrm{SO}_{2}(g) \longrightarrow \mathrm{H}_{2} \mathrm{SO}_{4}(a q) $$ The resulting sulfuric acid is then titrated with a standard NaOH solution. A 1.302 -g sample of coal is burned and the \(\mathrm{SO}_{2}\) is collected in a solution of hydrogen peroxide. It took \(28.44 \mathrm{mL}\) of a \(0.1000-M \mathrm{NaOH}\) solution to titrate the resulting sulfuric acid. Calculate the mass percent of sulfur in the coal sample. Sulfuric acid has two acidic hydrogens.

A \(10.00-\mathrm{g}\) sample consisting of a mixture of sodium chloride and potassium sulfate is dissolved in water. This aqueous mixture then reacts with excess aqueous lead(II) nitrate to form \(21.75 \mathrm{g}\) of solid. Determine the mass percent of sodium chloride in the original mixture.