Chapter 4

Calculating and Using pH A table wine has a pH of \(3.40 .\) What is the hydronium ion concentration of the wine? Is it acidic or basic?

A saturated solution of milk of magnesia, \(\mathrm{Mg}(\mathrm{OH})_{2},\) has a pH of \(10.5 .\) What is the hydronium ion concentration of the solution? Is the solution acidic or basic?

What is the hydronium ion concentration of a \(1.2 \times 10^{-4} \mathrm{M}\) solution of \(\mathrm{HClO}_{4} ?\) What is its \(\mathrm{pH}\) ?

Make the following conversions. In each case, tell whether the solution is acidic or basic. \(\mathbf{p} \mathbf{H}$$\quad$$\left[\mathbf{H}_{3} \mathbf{O}^{*}\right]\) (a) 1.00\(\quad\)______ (b) 10.50\(\quad\)______ (c) ______\(\quad1.3 \times 10^{-3} \mathrm{M}\) (d) ______\(\quad2.3 \times 10^{-8} \mathrm{M}\)

Make the following conversions. In each case, tell whether the solution is acidic or basic. \(\mathbf{p} \mathbf{H}$$\quad$$\left[\mathbf{H}_{3} \mathbf{O}^{*}\right]\) (a) \(\quad\)______\(\quad 6.7 \times 10^{-10} \mathrm{M}\) (b) \(\quad\)______\(\quad2.2 \times 10^{-6} \mathrm{M}\) (c) 5.25\(\quad\)_____ (d) ______\(\quad2.5 \times 10^{-2} \mathrm{M}\)

Stoichiometry of Reactions in Solution What volume of \(0.109 \mathrm{M} \mathrm{HNO}_{3},\) in milliliters, is required to react completely with \(2.50 \mathrm{g}\) of \(\mathrm{Ba}(\mathrm{OH})_{2} ?\) \(2 \mathrm{HNO}_{3}(\mathrm{aq})+\mathrm{Ba}(\mathrm{OH})_{2}(\mathrm{s}) \rightarrow\) $$ 2 \mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{Ba}\left(\mathrm{NO}_{3}\right)_{2}(\mathrm{aq}) $$

What mass of \(\mathrm{Na}_{2} \mathrm{CO}_{3},\) in grams, is required for complete reaction with \(50.0 \mathrm{mL}\) of \(0.125 \mathrm{M} \mathrm{HNO}_{3} ?\) \(\mathrm{Na}_{2} \mathrm{CO}_{3}(\mathrm{aq})+2 \mathrm{HNO}_{3}(\mathrm{aq}) \rightarrow\) $$ 2 \mathrm{NaNO}_{3}(\mathrm{aq})+\mathrm{CO}_{2}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\ell) $$

When an electric current is passed through an aqueous solution of NaCl, the valuable industrial chemicals \(\mathrm{H}_{2}(\mathrm{g}), \mathrm{Cl}_{2}(\mathrm{g}),\) and \(\mathrm{NaOH}\) are produced. \(2 \mathrm{NaCl}(\mathrm{aq})+2 \mathrm{H}_{2} \mathrm{O}(\ell) \rightarrow\) $$ \mathrm{H}_{2}(\mathrm{g})+\mathrm{Cl}_{2}(\mathrm{g})+2 \mathrm{NaOH}(\mathrm{aq}) $$

Hydrazine, \(\mathrm{N}_{2} \mathrm{H}_{4},\) a base like ammonia, can react with sulfuric acid. \(2 \mathrm{N}_{2} \mathrm{H}_{4}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{SO}_{4}(\mathrm{aq}) \rightarrow 2 \mathrm{N}_{2} \mathrm{H}_{5}+(\mathrm{aq})+\mathrm{SO}_{4}^{2-}(\mathrm{aq})\) What mass of hydrazine reacts with \(250 .\) mL. of \(0.146 \mathrm{M}\) \(\mathrm{H}_{2} \mathrm{SO}_{4} ?\)

In the photographic developing process, silver bromide is dissolved by adding sodium thiosulfate. \(\mathrm{AgBr}(\mathrm{s})+2 \mathrm{Na}_{2} \mathrm{S}_{2} \mathrm{O}_{3}(\mathrm{aq}) \rightarrow\) $$ \mathrm{Na}_{3} \mathrm{Ag}\left(\mathrm{S}_{2} \mathrm{O}_{3}\right)_{2}(\mathrm{aq})+\mathrm{NaBr}(\mathrm{aq}) $$ If you want to dissolve \(0.225 \mathrm{g}\) of \(\mathrm{AgBr}\), what volume of \(0.0138 \mathrm{M} \mathrm{Na}_{2} \mathrm{S}_{2} \mathrm{O}_{3},\) in milliliters, should be used? (IMAGE CANNOT COPY)

You can dissolve an aluminum soft drink can in an aqueous base such as potassium hydroxide. \(2 \mathrm{Al}(\mathrm{s})+2 \mathrm{KOH}(\mathrm{aq})+6 \mathrm{H}_{2} \mathrm{O}(\ell) \rightarrow\) $$ 2 \mathrm{KAl}(\mathrm{OH})_{4}(\mathrm{aq})+3 \mathrm{H}_{2}(\mathrm{g}) $$ If you place \(2.05 \mathrm{g}\) of aluminum in a beaker with \(185 \mathrm{mL}\) of \(1.35 \mathrm{M} \mathrm{KOH},\) will any aluminum remain? What mass of \(\mathrm{KAl}(\mathrm{OH})_{4}\) is produced?

What volume of \(0.750 \mathrm{M} \mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2},\) in milliliters, is required to react completely with \(1.00 \mathrm{L}\) of \(2.25 \mathrm{M} \mathrm{NaCl}\) solution? The balanced equation is \(\mathrm{Pb}\left(\mathrm{NO}_{3}\right)_{2}(\mathrm{aq})+2 \mathrm{NaCl}(\mathrm{aq}) \rightarrow\) $$ \mathrm{PbCl}_{2}(\mathrm{s})+2 \mathrm{NaNO}_{3}(\mathrm{aq}) $$

What volume of \(0.125 \mathrm{M}\) oxalic acid, \(\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4}\), is required to react with \(35.2 \mathrm{mL}\) of \(0.546 \mathrm{M} \mathrm{NaOH} ?\) \(\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4}(\mathrm{aq})+2 \mathrm{NaOH}(\mathrm{aq}) \rightarrow\) $$ \mathrm{Na}_{2} \mathrm{C}_{2} \mathrm{O}_{4}(\mathrm{aq})+2 \mathrm{H}_{2} \mathrm{O}(\ell) $$

Titrations What volume of \(0.812 \mathrm{M}\) HCl, in milliliters, is required to titrate \(1.45 \mathrm{g}\) of \(\mathrm{NaOH}\) to the equivalence point? $$ \mathrm{NaOH}(\mathrm{aq})+\mathrm{HCl}(\mathrm{aq}) \rightarrow \mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{NaCl}(\mathrm{aq}) $$

What volume of \(0.955 \mathrm{M}\) HCl, in milliliters, is required to titrate \(2.152 \mathrm{g}\) of \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) to the equivalence point? \(\mathrm{Na}_{2} \mathrm{CO}_{3}(\mathrm{aq})+2 \mathrm{HCl}(\mathrm{aq}) \rightarrow\) $$ \mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{CO}_{2}(\mathrm{g})+2 \mathrm{NaCl}(\mathrm{aq}) $$

If 38.55 mL of \(\mathrm{HCl}\) is required to titrate \(2.150 \mathrm{g}\) of \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) according to the following equation, what is the concentration \((\mathrm{mol} / \mathrm{L})\) of the HCl solution? \(\mathrm{Na}_{2} \mathrm{CO}_{3}(\mathrm{aq})+2 \mathrm{HCl}(\mathrm{aq}) \rightarrow\) \(2 \mathrm{NaCl}(\mathrm{aq})+\mathrm{CO}_{2}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\ell)\)

Potassium hydrogen phthalate, \(\mathrm{KHC}_{8} \mathrm{H}_{4} \mathrm{O}_{4},\) is used to standardize solutions of bases. The acidic anion reacts with strong bases according to the following net ionic equation: $$ \mathrm{HC}_{8} \mathrm{H}_{4} \mathrm{O}_{4}^{-}(\mathrm{aq})+\mathrm{OH}^{-}(\mathrm{aq}) \rightarrow{\mathrm{C}_{8} \mathrm{H}_{4} \mathrm{O}_{4}^{2-}(\mathrm{aq})}+\mathrm{H}_{2} \mathrm{O}(\ell) $$ If a \(0.902-\mathrm{g}\) sample of potassium hydrogen phthalate is dissolved in water and titrated to the equivalence point with \(26.45 \mathrm{mL}\) of \(\mathrm{NaOH},\) what is the molar concentration of the NaOH?

You have \(0.954 \mathrm{g}\) of an unknown acid, \(\mathrm{H}_{2} \mathrm{A}\), which reacts with NaOH according to the balanced equation $$ \mathrm{H}_{2} \mathrm{A}(\mathrm{aq})+2 \mathrm{NaOH}(\mathrm{aq}) \rightarrow \mathrm{Na}_{2} \mathrm{A}(\mathrm{aq})+2 \mathrm{H}_{2} \mathrm{O}(\ell) $$ If 36.04 mL of 0.509 M \(\mathrm{NaOH}\) is required to titrate the acid to the second equivalence point, what is the molar mass of the acid?

An unknown solid acid is either citric acid or tartaric acid. To determine which acid you have, you titrate a sample of the solid with aqueous \(\mathrm{NaOH}\) and from this determine the molar mass of the unknown acid. The appropriate equations are as follows: Citric acid: \(\mathrm{H}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7}(\mathrm{aq})+3 \mathrm{NaOH}(\mathrm{aq}) \rightarrow\) $$ 3 \mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{Na}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7}(\mathrm{aq}) $$ Tartanic acid: \(\mathrm{H}_{2} \mathrm{C}_{4} \mathrm{H}_{4} \mathrm{O}_{6}(\mathrm{aq})+2 \mathrm{NaOH}(\mathrm{aq}) \rightarrow\) $$ 2 \mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{Na}_{2} \mathrm{C}_{4} \mathrm{H}_{4} \mathrm{O}_{6}(\mathrm{aq}) $$ A \(0.956-\mathrm{g}\) sample requires \(29.1 \mathrm{mL}\) of \(0.513 \mathrm{M} \mathrm{NaOH}\) to consume the acid completely. What is the unknown acid?

To analyze an iron-containing compound, you convert all the iron to \(\mathrm{Fe}^{2+}\) in aqueous solution and then titrate the solution with standardized \(\mathrm{KMnO}_{4} .\) The balanced, net ionic equation is \(\mathrm{MnO}_{4}^{-}(\mathrm{aq})+5 \mathrm{Fe}^{2+}(\mathrm{aq})+8 \mathrm{H}_{3} \mathrm{O}^{+}(\mathrm{aq}) \rightarrow\) $$ \mathrm{Mn}^{2+}(\mathrm{aq})+5 \mathrm{Fe}^{3+}(\mathrm{aq})+12 \mathrm{H}_{2} \mathrm{O}(\ell) $$ A \(0.598-\mathrm{g}\) sample of the iron-containing compound requires \(22.25 \mathrm{mL}\) of \(0.0123 \mathrm{M} \mathrm{KMnO}_{4}\) for titration to the equivalence point. What is the mass percent of iron in the sample?

Vitamin C has the formula \(\mathrm{C}_{6} \mathrm{H}_{8} \mathrm{O}_{6} .\) Besides being an acid, it is a reducing agent. One method for determining the amount of vitamin \(\mathrm{C}\) in a sample is to titrate it with a solution of bromine, \(\mathrm{Br}_{2},\) an oxidizing agent. $$ \mathrm{C}_{6} \mathrm{H}_{8} \mathrm{O}_{6}(\mathrm{aq})+\mathrm{Br}_{2}(\mathrm{aq}) \rightarrow 2 \mathrm{HBr}(\mathrm{aq})+\mathrm{C}_{6} \mathrm{H}_{6} \mathrm{O}_{6}(\mathrm{aq}) $$ A \(1.00-\mathrm{g}\) "chewable" vitamin C tablet requires \(27.85 \mathrm{mL}\) of \(0.102 \mathrm{M} \mathrm{Br}_{2}\) for titration to the equivalence point. What is the mass of vitamin \(\mathrm{C}\) in the tablet?

Spectrophotometry A solution of a dye was analyzed by spectrophotometry, and the following calibration data were collected. $$\begin{array}{cc} \text { Dye Concentration } & \text { Absorbance }(A) \text { at } 475 \mathrm{nm} \\ \hline 0.50 \times 10^{-6} \mathrm{M} & 0.24 \\ 1.5 \times 10^{-6} \mathrm{M} & 0.36 \\ 2.5 \times 10^{-6} \mathrm{M} & 0.44 \\ 3.5 \times 10^{-6} \mathrm{M} & 0.59 \\ 4.5 \times 10^{-6} \mathrm{M} & 0.70 \\ \hline \end{array}$$ (a) Construct a calibration plot, and determine the slope and intercept. (b) What is the dye concentration in a solution with \(A=0.52 ?\)

The nitrite ion is involved in the biochemical nitrogen cycle. You can determine the nitrite ion content of a sample using spectrophotometry by first using several organic compounds to form a colored compound from the ion. The following data were collected. $$\begin{array}{cc} \begin{array}{c} \mathrm{NO}_{2} \text { - Ion } \\ \text { Concentration } \end{array} & \begin{array}{c} \text { Absorbance of Solution } \\ \text { at } 550 \mathrm{nm} \end{array} \\ \hline 2.00 \times 10^{-6} \mathrm{M} & 0.065 \\ 6.00 \times 10^{-6} \mathrm{M} & 0.205 \\ 10.00 \times 10^{-6} \mathrm{M} & 0.338 \\ 14.00 \times 10^{-6} \mathrm{M} & 0.474 \\ 18.00 \times 10^{-6} \mathrm{M} & 0.598 \\ \text { Unknown solution } & 0.402 \end{array}$$ (a) Construct a calibration plot, and determine the slope and intercept. (b) What is the nitrite ion concentration in the unknown solution?

These questions are not designated as to type or location in the chapter. They may combine several concepts. Suppose \(16.04 \mathrm{g}\) of benzene, \(\mathbf{C}_{6} \mathbf{H}_{6},\) is burned in oxygen. (a) What are the products of the reaction? (b) Write a balanced equation for the reaction. (c) What mass of \(\mathbf{O}_{2},\) in grams, is required for complete combustion of benzene? (d) What is the total mass of products expected from the combustion of \(16.04 \mathrm{g}\) of benzene?

Your body deals with excess nitrogen by excreting it in the form of urea, \(\mathrm{NH}_{2} \mathrm{CONH}_{2}\). The reaction producing it is the combination of arginine \(\left(\mathrm{C}_{6} \mathrm{H}_{14} \mathrm{N}_{4} \mathrm{O}_{2}\right)\) with water to give urea and ornithine \(\left(\mathrm{C}_{5} \mathrm{H}_{12} \mathrm{N}_{2} \mathrm{O}_{2}\right)\) $$ \mathrm{C}_{6} \mathrm{H}_{14} \mathrm{N}_{4} \mathrm{O}_{2}+\mathrm{H}_{2} \mathrm{O} \rightarrow \mathrm{NH}_{2} \mathrm{CONH}_{2}+\mathrm{C}_{5} \mathrm{H}_{12} \mathrm{N}_{2} \mathrm{O}_{2} $$ arginine ornithine If you excrete 95 mg of urea, what mass of arginine must have been used? What mass of ornithine must have been produced?

Some metal halides react with water to produce the metal oxide and the appropriate hydrogen halide (see photo). For example, $$ \mathrm{TiCl}_{4}(\ell)+2 \mathrm{H}_{2} \mathrm{O}(\ell) \rightarrow \mathrm{TiO}_{2}(\mathrm{s})+4 \mathrm{HCl}(\mathrm{g}) $$ (IMAGE CANNOT COPY) (a) Name the four compounds involved in this reaction. (b) If you begin with \(14.0 \mathrm{mL}\) of \(\mathrm{TiCl}_{4}(d=1.73 \mathrm{g} / \mathrm{mL})\) what mass of water, in grams, is required for complete reaction? (c) What mass of each product is expected?

The reaction of \(750 .\) g each of \(\mathrm{NH}_{3}\) and \(\mathrm{O}_{2}\) was found to produce \(562 \mathrm{g}\) of \(\mathrm{NO}\) (see pages \(161-162\) ). \(4 \mathrm{NH}_{3}(\mathrm{g})+5 \mathrm{O}_{2}(\mathrm{g}) \rightarrow 4 \mathrm{NO}(\mathrm{g})+6 \mathrm{H}_{2} \mathrm{O}(\ell)\) (a) What mass of water is produced by this reaction? (b) What mass of \(\mathrm{O}_{2}\) is required to consume \(750 . \mathrm{g}\) of \(\mathrm{NH}_{3} ?\)

Sodium azide, an explosive chemical used in automobile airbags, is made by the following reaction: $$ \mathrm{NaNO}_{3}+3 \mathrm{NaNH}_{2} \rightarrow \mathrm{NaN}_{3}+3 \mathrm{NaOH}+\mathrm{NH}_{3} $$ If you combine \(15.0 \mathrm{g}\) of \(\mathrm{NaNO}_{3}\) with \(15.0 \mathrm{g}\) of \(\mathrm{NaNH}_{2}\) what mass of \(\mathrm{NaN}_{3}\) is produced?

Iodine is made by the following reaction \(2 \mathrm{NaIO}_{3}(\mathrm{aq})+5 \mathrm{NaHSO}_{3}(\mathrm{aq}) \rightarrow\) $$ 3 \mathrm{NaHSO}_{4}(\mathrm{aq})+2 \mathrm{Na}_{2} \mathrm{SO}_{4}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{O}(\ell)+\mathrm{I}_{2}(\mathrm{aq}) $$ (a) Name the two reactants. (b) If you wish to prepare \(1.00 \mathrm{kg}\) of \(\mathrm{I}_{2},\) what masses of \(\mathrm{NalO}_{3}\) and \(\mathrm{NaHSO}_{3}\) are required? (c) What is the theoretical yield of \(I_{2}\) if you mixed \(15.0 \mathrm{g}\) of \(\mathrm{NaIO}_{3}\) with \(125 \mathrm{mL}\) of \(0.853 \mathrm{M} \mathrm{NaHSO}_{3} ?\)

A Boron forms a series of compounds with hydrogen, all with the general formula \(\mathrm{B}_{x} \mathrm{H}_{y}\) $$ \mathrm{B}_{x} \mathrm{H}_{y}(\mathrm{s})+\text { excess } \mathrm{O}_{2}(\mathrm{g}) \rightarrow \frac{x}{2} \mathrm{B}_{2} \mathrm{O}_{3}(\mathrm{s})+\frac{y}{2} \mathrm{H}_{2} \mathrm{O}(\mathrm{g}) $$ If \(0.148 \mathrm{g}\) of one of these compounds gives \(0.422 \mathrm{g}\) of \(\mathrm{B}_{2} \mathrm{O}_{3}\) when burned in excess \(\mathrm{O}_{2},\) what is its empirical formula?

A Silicon and hydrogen form a series of compounds with the general formula \(\mathrm{Si}_{1} \mathrm{H}_{\gamma}\). To find the formula of one of them, a \(6.22 \mathrm{g}\) sample of the compound is bumed in oxygen. All of the Si is converted to \(11.64 \mathrm{g}\) of \(\mathrm{SiO}_{2},\) and all of the \(\mathrm{H}\) is converted to \(6.980 \mathrm{g}\) of \(\mathrm{H}_{2} \mathrm{O}\). What is the empirical formula of the silicon compound?

A Menthol, from oil of mint, has a characteristic odor. The compound contains only \(\mathrm{C}, \mathrm{H},\) and \(\mathrm{O} .\) If \(95.6 \mathrm{mg}\) of menthol burns completely in \(\mathrm{O}_{2}\), and gives \(269 \mathrm{mg}\) of \(\mathrm{CO}_{2}\) and \(111 \mathrm{mg}\) of \(\mathrm{H}_{2} \mathrm{O},\) what is the empirical formula of menthol?

A Benzoquinone, a chemical used in the dye industry and in photography, is an organic compound containing only C, \(\mathrm{H}\), and O. What is the empirical formula of the compound if \(0.105 \mathrm{g}\) of the compound gives \(0.257 \mathrm{g}\) of \(\mathrm{CO}_{2}\) and \(0.0350 \mathrm{g}\) of \(\mathrm{H}_{2} \mathrm{O}\) when burned completely in oxygen?

Aqueous solutions of iron(II) chloride and sodium sulfide react to form iron(11)sulfide and sodium chloride. (a) Write the balanced equation for the reaction. (b) If you combine \(40 .\) g each of \(\mathrm{Na}_{2} \mathrm{S}\) and \(\mathrm{FeCl}_{2}\), what is the limiting reactant? (c) What mass of FeS is produced? (d) What mass of NasS or FeCl, remains after the reaction? (e) What mass of \(\mathrm{FeCl}_{2}\) is required to react completely with \(40 . \mathrm{g}\) of \(\mathrm{Na}_{2} \mathrm{S} ?\)

A An unknown metal reacts with oxygen to give the metal oxide, MO, Identify the metal if a \(0.356-\mathrm{g}\) sample of the metal produces \(0.452 \mathrm{g}\) of the metal oxide.

A Titanium(IV) oxide, \(\mathrm{TiO}_{2}\), is heated in hydrogen gas to give water and a new titanium oxide, \(\mathrm{Ti}_{x} \mathrm{O}_{y}\). If \(1.598 \mathrm{g}\) of \(\mathrm{TiO}_{2}\) produces \(1.438 \mathrm{g}\) of \(\mathrm{Ti}_{2} \mathrm{O}_{y},\) what is the empirical formula of the new oxide?

A Potassium perchlorate is prepared by the following sequence of reactions: \(\mathrm{Cl}_{2}(\mathrm{g})+2 \mathrm{KOH}(\mathrm{aq}) \rightarrow\) $$ \mathrm{KCl}(\mathrm{aq})+\mathrm{KClO}(\mathrm{aq})+\mathrm{H}_{2} \mathrm{O}(\ell) $$ \(3 \mathrm{KClO}(\mathrm{aq}) \rightarrow 2 \mathrm{KCl}(\mathrm{aq})+\mathrm{KClO}_{3}(\mathrm{aq})\) \(4 \mathrm{KClO}_{3}(\mathrm{aq}) \rightarrow 3 \mathrm{KClO}_{4}(\mathrm{aq})+\mathrm{KCl}(\mathrm{aq})\) What mass of \(\mathrm{Cl}_{2}(\mathrm{g})\) is required to produce \(234 \mathrm{kg}\) of \(\mathrm{KClO}_{4} ?\)

A Commercial sodium "hydrosulfite" is \(90.1 \%\) \(\mathrm{Na}_{2} \mathrm{S}_{2} \mathrm{O}_{4} .\) The sequence of reactions used to prepare the compound is $$ \mathrm{Zn}(\mathrm{s})+2 \mathrm{SO}_{2}(\mathrm{g}) \rightarrow \mathrm{ZnS}_{2} \mathrm{O}_{4}(\mathrm{s}) $$ \(\mathrm{ZnS}_{2} \mathrm{O}_{4}(\mathrm{s})+\mathrm{Na}_{2} \mathrm{CO}_{3}(\mathrm{aq}) \rightarrow \mathrm{ZnCO}_{3}(\mathrm{s})+\mathrm{Na}_{2} \mathrm{S}_{2} \mathrm{O}_{4}(\mathrm{aq})\) (a) What mass of pure \(\mathrm{Na}_{2} \mathrm{S}_{2} \mathrm{O}_{4}\) can be prepared from \(125 \mathrm{kg}\) of \(\mathrm{Zn}, 500 . \mathrm{g}\) of \(\mathrm{SO}_{2},\) and an excess of \(\mathrm{Na}_{2} \mathrm{CO}_{3} ?\) (b) What mass of the commercial product would contain the \(\mathrm{Na}_{2} \mathrm{S}_{2} \mathrm{O}_{4}\) produced using the amounts of reactants in part (a)?

What mass of lime, CaO, can be obtained by heating \(125 \mathrm{kg}\) of limestone that is \(95.0 \%\) by mass \(\mathrm{CaCO}_{3} ?\) $$ \mathrm{CaCO}_{3}(\mathrm{s}) \rightarrow \mathrm{CaO}(\mathrm{s})+\mathrm{CO}_{2}(\mathrm{g}) $$

A The elements silver, molybdenum, and sulfur combine to form AgaMoS., What is the maximum mass of \(\mathrm{Ag}_{2} \mathrm{MoS}_{4}\) that can be obtained if \(8.63 \mathrm{g}\) of silver, \(3.36 \mathrm{g}\) of molybdenum, and \(4.81 \mathrm{g}\) of sulfur are combined? (Hint: What is the limiting reactant?)

A A mixture of butene, \(C_{4} H_{8},\) and butane, \(C_{4} H_{10},\) is burned in air to give \(\mathrm{CO}_{2}\) and water. Suppose you burn \(2.86 \mathrm{g}\) of the mixture and obtain \(8.80 \mathrm{g}\) of \(\mathrm{CO}_{2}\) and \(4.14 \mathrm{g}\) of \(\mathrm{H}_{2} \mathrm{O} .\) What are the mass percentages of butene and butane in the mixture?

A Cloth can be waterproofed by coating it with a silicone layer. This is done by exposing the cloth to \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{SiCl}_{2}\) vapor. The silicon compound reacts with OH groups on the cloth to form a waterproofing film (density \(=1.0 \mathrm{g} / \mathrm{cm}^{3}\) ) of \(\left[\left(\mathrm{CH}_{3}\right)_{2} \mathrm{SiO}\right]_{m},\) where \(n\) is a large integer number. \(n\left(\mathrm{CH}_{3}\right)_{2} \mathrm{SiCl}_{2}+2 n \mathrm{OH}^{-} \rightarrow\) $$ 2 n \mathrm{Cl}^{-}+n \mathrm{H}_{2} \mathrm{O}+\left[\left(\mathrm{CH}_{3}\right)_{2} \mathrm{SiO}\right]_{n} $$ The coating is added layer by layer, with each layer of \(\left[\left(\mathrm{CH}_{3}\right)_{2} \mathrm{SiO}\right]_{n}\) being \(0.60 \mathrm{nm}\) thick. Suppose you want to waterproof a piece of cloth that is 3.00 square meters, and you want 250 layers of waterproofing compound on the cloth. What mass of \(\left(\mathrm{CH}_{3}\right)_{2} \mathrm{SiCl}_{2}\) do you need?

A Copper metal can be prepared by roasting copper ore, which can contain cuprite \(\left(\mathrm{Cu}_{2} \mathrm{S}\right)\) and copper (11) sulfide. $$ \begin{aligned} \mathrm{Cu}_{2} \mathrm{S}(\mathrm{s})+\mathrm{O}_{2}(g) & \rightarrow 2 \mathrm{Cu}(\mathrm{s})+\mathrm{SO}_{2}(\mathrm{g}) \\ \mathrm{CuS}(\mathrm{s})+\mathrm{O}_{2}(\mathrm{g}) & \rightarrow \mathrm{Cu}(\mathrm{s})+\mathrm{SO}_{2}(\mathrm{g}) \end{aligned} $$ Suppose an ore sample contains \(11.0 \%\) impurity in addition to a mixture of CuS and Cu \(_{2} \mathrm{S}\). Heating \(100.0 \mathrm{g}\) of the mixture produces \(75.4 \mathrm{g}\) of copper metal with a purity of \(89.5 \% .\) What is the weight percent of CuS in the ore? The weight percent of \(\mathrm{Cu}_{2} \mathrm{S} ?\)

Which has the larger concentration of hydronium ions, \(0.015 \mathrm{M} \mathrm{HCl}\) or aqueous \(\mathrm{HCl}\) with a \(\mathrm{pH}\) of \(1.20 ?\)

An Alka-Seltzer tablet contains exactly \(100 .\) mg of citric acid, \(\mathrm{H}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7},\) plus some sodium bicarbonate. What mass of sodium bicarbonate is required to consume \(100 .\) mg of citric acid by the following reaction? \(\mathrm{H}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7}(\mathrm{aq})+3 \mathrm{NaHCO}_{3}(\mathrm{aq}) \rightarrow\) $$ 3 \mathrm{H}_{2} \mathrm{O}(\ell)+3 \mathrm{CO}_{2}(\mathrm{g})+\mathrm{Na}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7}(\mathrm{aq}) $$

A Sodium bicarbonate and acetic acid react according to the equation \(\mathrm{NaHCO}_{3}(\mathrm{aq})+\mathrm{CH}_{3} \mathrm{CO}_{2} \mathrm{H}(\mathrm{aq}) \rightarrow\) $$ \mathrm{NaCH}_{3} \mathrm{CO}_{2}(\mathrm{aq})+\mathrm{CO}_{2}(\mathrm{g})+\mathrm{H}_{2} \mathrm{O}(\ell) $$ What mass of sodium acetate can be obtained from mixing \(15.0 \mathrm{g}\) of \(\mathrm{NaHCO}_{3}\) with \(125 \mathrm{mL}\) of \(0.15 \mathrm{M}\) acetic acid?

A noncarbonated soft drink contains an unknown amount of citric acid, \(\mathrm{H}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7} .\) If \(100 .\) mL of the soft drink requires \(33.51 \mathrm{mL}\) of \(0.0102 \mathrm{M} \mathrm{NaOH}\) to neutralize the citric acid completely, what mass of citric acid does the soft drink contain per \(100 .\) mL? The reaction of citric acid and NaOH is \(\mathrm{H}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7}(\mathrm{aq})+3 \mathrm{NaOH}(\mathrm{aq}) \rightarrow\) $$ \mathrm{Na}_{3} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{O}_{7}(\mathrm{aq})+3 \mathrm{H}_{2} \mathrm{O}(\ell) $$

Sodium thiosulfate, \(\mathrm{Na}_{2} \mathrm{S}_{2} \mathrm{O}_{3},\) is used as a "fixer" in black-and-white photography. Suppose you have a botule of sodium thiosulfate and want to determine its purity. The thiosulfate ion can be oxidized with \(\mathrm{I}_{2}\) according to the balanced, net ionic equation $$ \mathrm{I}_{2}(\mathrm{aq})+2 \mathrm{S}_{2} \mathrm{O}_{3}^{2-}(\mathrm{aq}) \rightarrow 2 \mathrm{I}^{-}(\mathrm{aq})+\mathrm{S}_{4} \mathrm{O}_{6}^{2-}(\mathrm{aq}) $$ If you use \(40.21 \mathrm{mL}\) of \(0.246 \mathrm{M} \mathrm{I}_{2}\) in a titration, what is the weight percent of \(\mathrm{Na}_{2} \mathrm{S}_{2} \mathrm{O}_{3}\) in a \(3.232-\mathrm{g}\) sample of impure material?

You have a mixture of oxalic acid, \(\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4},\) and another solid that does not react with sodium hydroxide. If \(29.58 \mathrm{mL}\) of \(0.550 \mathrm{M} \mathrm{NaOH}\) is required to titrate the oxalic acid in the 4.554 -g sample to the second equivalence point, what is the mass percent of oxalic acid in the mixture? Oxalic acid and NaOH react according to the equation \(\mathrm{H}_{2} \mathrm{C}_{2} \mathrm{O}_{4}(\mathrm{aq})+2 \mathrm{NaOH}(\mathrm{aq}) \rightarrow\) $$ \mathrm{Na}_{2} \mathrm{C}_{2} \mathrm{O}_{4}(\mathrm{aq})+2 \mathrm{H}_{2} \mathrm{O}(\ell) $$

A solution of hydrochloric acid has a volume of \(125 \mathrm{mL}\) and a pH of \(2.56 .\) What mass of \(\mathrm{NaHCO}_{3}\) must be added to completely consume the HCl?