Three Major Classes of Chemical Reactions

If 26.25 mL of a standard 0.1850 M NaOH solution is required to neutralize 25.00 mL of ${\mathbf{\text{H}}}_{\mathbf{\text{2}}}{\mathbf{\text{SO}}}_{\mathbf{\text{4}}}\mathbf{\text{,}}$ what is the molarity of the acid solution?

One of the first steps in the enrichment of uranium for use in nuclear power plants involves a displacement reaction between ${\mathbf{UO}}_{\mathbf{2}}\mathbf{?}$ and aqueous HF: 

${\mathbf{UO}}_{\mathbf{2}}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{+}\mathbf{HF}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{\to }{\mathbf{UF}}_{\mathbf{4}}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{+}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{\left(}\mathbf{l}\mathbf{\right)}\mathbf{\left(}\mathbf{unbalanced}\mathbf{\right)}$

How many liters of 2.40 M HF will react with 2.15 kg of  ${\mathbf{UO}}_{\mathbf{2}}\mathbf{?}$

A mixture of bases can sometimes be the active ingredient in antacid tablets. If 0.4826 g of a mixture of ${\mathbf{\text{Al(OH)}}}_{\mathbf{\text{3}}}$ and  $\mathbf{\text{Mg}}{\mathbf{\left(}\mathbf{\text{OH}}\mathbf{\right)}}_{\mathbf{\text{2}}}$is neutralized with 17.30 mL of 1.000 M  ${\mathbf{\text{HNO}}}_{\mathbf{\text{3}}}\mathbf{\text{,}}$ what is the mass % of  ${\mathbf{\text{Al(OH)}}}_{\mathbf{\text{3}}}$ in the mixture?

Give the oxidation number of bromine in the following

$$\begin{gathered} \left(a\right)\mathit{K}\mathit{B}\mathit{r} \\ \left(b\right)\mathit{B}\mathit{r}{\mathit{F}}_{\mathbf{3}} \\ \left(c\right)\mathit{H}\mathit{B}\mathit{r}{\mathit{O}}_{\mathbf{3}}^{} \\ \left(d\right)\mathit{C}\mathit{B}{\mathit{r}}_{\mathbf{4}} \end{gathered}$$

Give the oxidation number of carbon in the following:

$$\begin{gathered} \left(a\right)\mathit{C}{\mathit{F}}_{\mathbf{2}}\mathit{C}{\mathit{l}}_{\mathbf{2}} \\ \left(b\right)\mathit{N}{\mathit{a}}_{\mathbf{2}}{\mathit{C}}_{\mathbf{2}}{\mathit{O}}_{\mathbf{4}} \\ \left(c\right)\mathit{H}\mathit{C}{\mathit{O}}_{\mathbf{3}}^{\mathbf{-}} \\ \left(d\right){\mathit{C}}_{\mathbf{2}}{\mathit{H}}_{\mathbf{6}} \end{gathered}$$

$\mathbf{8}\mathit{N}{\mathit{H}}_{\mathbf{3}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{+}\mathbf{6}\mathit{N}{\mathit{O}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{\to }\mathbf{7}{\mathit{N}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{+}\mathbf{12}{\mathit{H}}_{\mathbf{2}}\mathit{O}\mathbf{\left(}\mathbf{l}\mathbf{\right)}$Identify the oxidizing agent and the reducing agent in the following reaction, and explain your answer:

In which of the following equations does sulfuric acid act as an oxidizing agent? In which does it act as an acid? Explain.

 $$\begin{gathered} \mathbf{\left(}\mathbf{a}\mathbf{\right)}\mathbf{4}{\mathit{H}}^{\mathbf{+}}\mathbf{\left(}\mathbf{a}\mathbf{q}\mathbf{\right)}\mathbf{+}\mathit{S}{\mathit{O}}_{\mathbf{4}}^{\mathbf{2}\mathbf{-}}\mathbf{\left(}\mathbf{a}\mathbf{q}\mathbf{\right)}\mathbf{+}\mathbf{2}\mathit{N}\mathit{a}\mathit{I}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{\to }\mathbf{2}\mathit{N}{\mathit{a}}^{\mathbf{+}}\mathbf{\left(}\mathbf{a}\mathbf{q}\mathbf{\right)}\mathbf{+}{\mathit{I}}_{\mathbf{2}}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{+}\mathit{S}{\mathit{O}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{+}\mathbf{2}{\mathit{H}}_{\mathbf{2}}\mathit{O}\mathbf{\left(}\mathbf{l}\mathbf{\right)} \\ \mathbf{\left(}\mathbf{b}\mathbf{\right)}\mathit{B}\mathit{a}{\mathit{F}}_{\mathbf{2}}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{+}\mathbf{2}{\mathit{H}}^{\mathbf{+}}\mathbf{\left(}\mathbf{a}\mathbf{q}\mathbf{\right)}\mathbf{+}\mathit{S}{\mathit{O}}_{\mathbf{4}}^{\mathbf{2}\mathbf{-}}\mathbf{\left(}\mathbf{a}\mathbf{q}\mathbf{\right)}\mathbf{\to }\mathbf{2}\mathit{H}\mathit{F}\mathbf{\left(}\mathbf{a}\mathbf{q}\mathbf{\right)}\mathbf{+}\mathit{B}\mathit{a}\mathit{S}{\mathit{O}}_{\mathbf{4}}\mathbf{\left(}\mathbf{s}\mathbf{\right)} \end{gathered}$$

Give the oxidation number of nitrogen in the following:

$$\begin{gathered} \left(a\right)\mathit{N}{\mathit{H}}_{\mathbf{2}}\mathit{O}\mathit{H} \\ \left(b\right){\mathit{N}}_{\mathbf{2}}{\mathit{F}}_{\mathbf{4}} \\ \left(c\right)\mathit{N}{\mathit{H}}_{\mathbf{4}}^{\mathbf{+}} \\ \left(d\right)\mathit{H}\mathit{N}\mathit{O} \end{gathered}$$

Give one example of a combination reaction that is a redox reaction and another that is not a redox reaction.

Balance each of the following redox reactions and classify it as a combination, decomposition, or displacement reaction:

$\left(\mathit{a}\right)\mathit{M}\mathit{g}\left(\mathit{s}\right)\mathbf{+}{\mathit{H}}_{\mathbf{2}}\mathit{O}\left(\mathit{g}\right)\mathbf{\to }\mathit{M}\mathit{g}{\left(\mathit{O}\mathit{H}\right)}_{\mathbf{2}}\left(\mathit{s}\right)\mathbf{+}{\mathit{H}}_{\mathbf{2}}\left(\mathit{g}\right)$

$\left(\mathit{b}\right)\mathit{C}\mathit{r}{\left(\mathit{N}{\mathit{O}}_3\right)}_{\mathbf{3}}\left(\mathit{a}\mathit{q}\right)\mathbf{+}\mathit{A}\mathit{l}\left(\mathit{s}\right)\mathbf{\to }\mathit{A}\mathit{l}{\left(\mathit{N}{\mathit{O}}_3\right)}_{\mathbf{3}}\left(\mathit{a}\mathit{q}\right)\mathbf{+}\mathit{C}\mathit{r}\left(\mathit{s}\right)$

Predict the product(s) and write a balanced equation for each of the following redox reactions:

$\left(\mathit{a}\right)\mathit{S}\mathit{r}\left(\mathit{s}\right)\mathbf{+}\mathit{B}{\mathit{r}}_{\mathbf{2}}\left(\mathit{l}\right)\mathbf{\to }$

$\left(\mathit{b}\right)\mathit{A}{\mathit{g}}_{\mathbf{2}}\mathit{O}\left(\mathit{s}\right)\stackrel{\mathbf{\Delta }}{\mathbf{\to }}$

$\left(\mathit{c}\right)\mathit{M}\mathit{n}\left(\mathit{s}\right)\mathbf{+}\mathit{C}\mathit{u}{\left(\mathit{N}{\mathit{O}}_3\right)}_{\mathbf{2}}\left(\mathit{a}\mathit{q}\right)\mathbf{\to }$

Predict the product(s) and write a balanced equation for each of the following redox reactions:

$\left(\mathit{a}\right)\mathit{M}\mathit{g}\left(\mathit{s}\right)\mathbf{+}\mathit{H}\mathit{C}\mathit{l}\left(\mathit{a}\mathit{q}\right)\mathbf{\to }$

$\mathbf{\left(}\mathbf{b}\mathbf{\right)}\mathit{L}\mathit{i}\mathit{C}\mathit{l}\mathbf{\left(}\mathbf{l}\mathbf{\right)}\stackrel{\mathbf{eletricity}}{\mathbf{\to }}$$\left(\mathit{b}\right)\mathit{L}\mathit{i}\mathit{C}\mathit{l}\left(\mathit{l}\right)\stackrel{\mathbf{e}\mathbf{l}\mathbf{e}\mathbf{t}\mathbf{r}\mathbf{i}\mathbf{c}\mathbf{i}\mathbf{t}\mathbf{y}}{\mathbf{\to }}$

$\left(\mathit{c}\right)\mathit{S}\mathit{n}\mathit{C}{\mathit{l}}_{\mathbf{2}}\left(\mathit{a}\mathit{q}\right)\mathbf{+}\mathit{C}\mathit{o}\left(\mathit{s}\right)\mathbf{\to }$

Balance each of the following redox reactions and classify it as a combination, decomposition, or displacement reaction:

$\left(\mathit{a}\right)\mathit{S}\mathit{b}\left(\mathit{s}\right)\mathbf{+}\mathit{C}{\mathit{l}}_{\mathbf{2}}\left(\mathit{g}\right)\mathbf{\to }\mathit{S}\mathit{b}\mathit{C}{\mathit{l}}_{\mathbf{3}}\left(\mathit{s}\right)$

$\left(\mathit{b}\right)\mathit{A}\mathit{s}{\mathit{H}}_{\mathbf{3}}\left(\mathit{g}\right)\mathbf{\to }\mathit{A}\mathit{s}\left(\mathit{s}\right)\mathbf{+}{\mathit{H}}_{\mathbf{2}}\left(\mathit{g}\right)$

$\left(\mathit{c}\right)\mathit{Z}\mathit{n}\left(\mathit{s}\right)\mathbf{+}\mathit{F}\mathit{e}{\left(\mathit{N}{\mathit{O}}_3\right)}_{\mathbf{2}}\left(\mathit{a}\mathit{q}\right)\mathbf{\to }\mathit{Z}\mathit{n}{\left(\mathit{N}{\mathit{O}}_3\right)}_{\mathbf{2}}\left(\mathit{a}\mathit{q}\right)\mathbf{+}\mathit{F}\mathit{e}\left(\mathit{s}\right)$

Balance each of the following redox reactions and classify it as a combination, decomposition, or displacement reaction:

$\left(a\right)HI\left(g\right)\to H_2\left(g\right)+I_2\left(g\right)$

$\left(b\right)Zn\left(s\right)+AgN{O}_3\left(aq\right)\to Zn{\left(N{O}_3\right)}_2\left(aq\right)+Ag\left(s\right)$

$\left(c\right)NO\left(g\right)+O_2\left(g\right)\to N_2{O}_4\left(l\right)$

Balance each of the following redox reactions and classify it as a combination, decomposition, or displacement reaction:

$\left(a\right)Ca\left(s\right)+H_{2}O\left(l\right)\to Ca{\left(OH\right)}_2\left(aq\right)+H_2\left(g\right)$

$\left(b\right)NaN{O}_3\left(s\right)\to NaN{O}_2\left(s\right)+O_2\left(g\right)$

$\left(c\right)C_2{H}_2\left(g\right)+H_2\left(g\right)\to C_2{H}_6\left(g\right)$

Identify the oxidizing and reducing agents in the following:

$$\begin{gathered} \left(a\right)8H^{+}\left(aq\right)+C{r}_2{O}_7^{2-}\left(aq\right)+3S{O}_3^{2-}\left(aq\right)\to 2C{r}^{3+}\left(aq\right)+3S{O}_4^{2-}\left(aq\right)+4H_{2}O\left(l\right) \\ \left(b\right)N{O}_3^{-}\left(aq\right)+4Zn\left(s\right)+7O{H}^{-}\left(aq\right)+6H_{2}O\left(l\right)\to 4Zn{\left(OH\right)}_4^{2-}\left(aq\right)+N{H}_3\left(aq\right) \end{gathered}$$

A person’s blood alcohol (C₂H₅OH) level can be determined by titrating a sample of blood plasma with a potassium dichromate solution. The balanced equation is

 $16H^{+}\left(aq\right)+2C{r}_2{O}_7^{2-}\left(aq\right)+C_2{H}_{5}OH\left(aq\right)\to 4C{r}^{3+}\left(aq\right)+2C{O}_2\left(g\right)+11H_{2}O\left(l\right)$

If 35.46mL of 0.05961M Cr₂O₇^2- is required to titrate 28.00 g of plasma, what is the mass percent of alcohol in the blood?

Which type of redox reaction leads to the following?

(a) An increase in the number of substances

(b) A decrease in the number of substances

(c) No change in the number of substances

Are all combustion reactions redox reactions? Explain

Give one example of a combination reaction that is a redox reaction and another that is not a redox reaction.

Predict the product(s) and write a balanced equation for each of the following redox reactions:

$\left(a\right)\mathbf{ }\mathbf{Fe}\left(s\right)\mathbf{+}{\mathbf{HClO}}_{\mathbf{4}}\left(\mathrm{aq}\right)\mathbf{\to }$

$\left(b\right){\mathbf{S}}_{\mathbf{8}}\left(s\right)\mathbf{+}{\mathbf{O}}_{\mathbf{2}}\left(g\right)\mathbf{\to }$

$\left(c\right) {\mathbf{BaCl}}_{\mathbf{2}}\left(l\right)\stackrel{\mathbf{electricity}}{\mathbf{\to }}$

Predict the product(s) and write a balanced equation for each of the following redox reactions:

(a) Pentane (C₅H₁₂) + Oxygen →

(b) Phosphorus trichloride + Chlorine →

(c) Zinc + Hydrobromic acid →

(d) Aqueous Potassium iodide + Bromine →

(e) Write a balanced net ionic equation for (d).

In a combination reaction, 1.62 g of lithium is mixed with 6.50 g of oxygen. 

(a) Which reactant is present in excess? 

(b) How many moles of product are formed? 

(c) After reaction, how many grams of each reactant and product are present?

When either a mixture of NO and Br₂ or pure nitrosyl bromide (NOBr) is placed in a reaction vessel, the product mixture contains NO, Br₂, and NOBr. Explain.

A mixture of KClO₃ and KCl with a mass of 0.950 g was heated to produce O₂. After heating, the mass of residue was 0.700g. Assuming all the KClO₃ decomposed to KCl and O₂, calculate the mass percent of KClO₃ in the original mixture.

Ammonia is produced by the millions of tons annually for use as a fertilizer. It is commonly made from N₂ and H₂ by the Haber process. Because the reaction reaches equilibrium before going completely to product, the stoichiometric amount of ammonia is not obtained. At a particular temperature and pressure, 10.0 g of H₂ reacts with 20.0 g of N₂ to form ammonia. When equilibrium is reached, 15.0 g of NH₃ has formed. 

(a) Calculate the percent yield. 

(b) How many moles of N₂ and H₂ are present at equilibrium?

A mixture of CaCO₃ and CaO weighing 0.693 g was heated to produce gaseous CO₂. After heating, the remaining solid weighed 0.508g. Assuming all the CaCO₃ broke down to CaO and CO₂, calculate the mass percent of CaCO₃ in the original mixture.

Nutritional biochemists have known for decades that acidic foods cooked in cast-iron cookware can supply significant amounts of dietary iron (ferrous ion).

(a) Write a balanced net ionic equation, with oxidation numbers, that supports this fact.

(b) Measurements show an increase from 3.3 mg of iron to 49 mg of iron per $\frac{\mathbf{1}}{\mathbf{2}}$ -cup (125-g) serving during the slow preparation of tomato sauce in a cast-iron pot. How many ferrous ions are present in a 26-oz (737-g) jar of the tomato sauce?

Limestone (CaCO₃) is used to remove acidic pollutants from smokestack flue gases. It is heated to form lime (CaO), which reacts with sulfur dioxide to form calcium sulfite. Assuming a 70.% yield in the overall reaction, what mass of limestone is required to remove all the sulfur dioxide formed by the combustion of 8.510⁴ kg of coal that is 0.33 mass % sulfur?

The brewing industry uses yeast microorganisms to convert glucose to ethanol for wine and beer. The baking industry uses the carbon dioxide produced to make bread rise:

 ${\mathbf{C}}_{\mathbf{6}}{\mathbf{H}}_{\mathbf{12}}{\mathbf{O}}_{\mathbf{6}}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\stackrel{\mathbf{yeast}}{\mathbf{\to }}\mathbf{2}{\mathbf{C}}_{\mathbf{2}}{\mathbf{H}}_{\mathbf{5}}\mathbf{OH}\mathbf{\left(}\mathbf{l}\mathbf{\right)}\mathbf{+}\mathbf{2}{\mathbf{CO}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}$

How many grams of ethanol can be produced from 100g of glucose? What volume of CO₂ is produced? (Assume 1 mol of gas occupies 22.4 L at the conditions used.)

A chemical engineer determines the mass percent of iron in an ore sample by converting the Fe to Fe²⁺ in acid and then titrating the Fe²⁺ with MnO₄^-. A 1.1081-g sample was dissolved in acid and then titrated with 39.32mL of 0.03190M KMnO₄. The balanced equation is

 $\mathbf{8}{\mathbf{H}}^{\mathbf{+}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}\mathbf{5}{\mathbf{Fe}}^{\mathbf{2}\mathbf{+}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}{\mathbf{MnO}}_{\mathbf{4}}^{\mathbf{-}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{\to }\mathbf{5}{\mathbf{Fe}}^{\mathbf{3}\mathbf{+}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}{\mathbf{Mn}}^{\mathbf{2}\mathbf{+}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}\mathbf{4}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{\left(}\mathbf{l}\mathbf{\right)}$

Calculate the mass percent of iron in the ore.

Before arc welding was developed, a displacement reaction involving aluminum and iron (III) oxide was commonly used to produce molten iron (the thermite process). This reaction was used, for example, to connect sections of iron railroad track. Calculate the mass of molten iron produced when 1.50 kg of aluminum reacts with 25.0 mol of iron (III) oxide.

Iron reacts rapidly with chlorine gas to form a reddish brown, ionic compound (A), which contains iron in the higher of its two common oxidation states. Strong heating decomposes compound A to compound B, another ionic compound, which contains iron in the lower of its two oxidation states. When compound A is formed by the reaction of 50.6 g of Fe and 83.8 g of Cl₂ and then heated, how much compound B forms?

Why the equilibrium state is called “dynamic”?

In a decomposition reaction involving a gaseous product, what must be done for the reaction to reach equilibrium?

Describe what happens on the molecular level when acetic acid dissolves in water.

Predict the product(s) and write a balanced equation for each of the following redox reactions:

$\mathbf{\left(}\mathbf{a}\mathbf{\right)}{\mathit{N}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{+}{\mathit{H}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{\to }$

$\mathbf{\left(}\mathbf{c}\mathbf{\right)}\mathit{B}\mathit{a}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{+}{\mathit{H}}_{\mathbf{2}}\mathit{O}\mathbf{\left(}\mathbf{l}\mathbf{\right)}\mathbf{\to }$

Predict the product(s) and write a balanced equation for each of the following redox reactions:

(a) Cesium + Iodine →

(b) Aluminum + aqueous Manganese(II) sulfate →

(c) Sulfur dioxide + Oxygen →

(d) Butane and Oxygen →

(e) Write a balanced net ionic equation for (b).

How many grams of O₂ can be prepared from the thermal decomposition of 4.27 kg of HgO? Name and calculate the mass (in kg) of the other product.

In a combination reaction, 2.22 g of magnesium is heated with 3.75 g of nitrogen. 

(a) Which reactant is present in excess? 

(b) How many moles of product are formed? 

(c) After reaction, how many grams of each reactant and product are present?

Mixtures of CaCl₂ and NaCl are used to melt ice on roads. A dissolved 1.9348-g sample of such a mixture was analyzed by using excess Na₂C₂O₄ to precipitate the Ca²⁺ as CaC₂O₄. The CaC₂O₄ was dissolved in sulfuric acid, and the resulting H₂C₂O₄ was titrated with 37.68mL of 0.1019M KMnO₄ solution.

(a) Write the balanced net ionic equation for the precipitation reaction.

(b) Write the balanced net ionic equation for the titration reaction. (See Sample Problem 4.11.) 

(c) What is the oxidizing agent? 

(d) What is the reducing agent? 

(e) Calculate the mass percent of CaCl₂ in the original sample.

You are given solutions of HCl and NaOH and must determine their concentrations. You use 27.5mL of NaOH to titrate 100mL of HCl and 18.4mL of NaOH to titrate 50.0mL of 0.0782M H₂SO₄. Find the unknown concentrations.

The flask represents the products of the titration of 25mL of sulfuric acid with 25mL of sodium hydroxide.

(a) Write balanced molecular, total ionic, and net ionic equations for the reaction.

(b) If each orange sphere represents 0.010 mol of sulfate ion, how many moles of acid and of base reacted?

(c) What are the molarities of the acid and the base?

To find the mass percent of dolomite CaMg(CO₃)₂ in a soil sample, a geochemist titrates 13.86g of soil with 33.56mL of 0.2516M HCl. What is the mass percent of dolomite in the soil?

On a lab exam, you have to find the concentrations of the monoprotic (one proton per molecule) acids HA and HB. You are given 43.5mL of HA solution in one flask. A second flask contains 37.2mL of HA, and you add enough HB solution to it to reach a final volume of 50.0mL. You titrate the first HA solution with 87.3mL of 0.0906M NaOH and the mixture of HA and HB in the second flask with 96.4mL of the NaOH solution. Calculate the molarity of the HA and HB solutions.

Nitric acid, a major industrial and laboratory acid, is produced commercially by the multistep Ostwald process, which begins with the oxidation of ammonia:

Step 1. $\mathbf{4}{\mathbf{NH}}_{\mathbf{3}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{+}\mathbf{5}{\mathbf{O}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{\to }\mathbf{4}\mathbf{NO}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{+}\mathbf{6}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{\left(}\mathbf{l}\mathbf{\right)}$

Step 2. $\mathbf{2}\mathbf{NO}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{+}{\mathbf{O}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{\to }\mathbf{2}{\mathbf{NO}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}$      

Step 3.  $\mathbf{3}{\mathbf{NO}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{+}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{\left(}\mathbf{l}\mathbf{\right)}\mathbf{\to }\mathbf{2}{\mathbf{HNO}}_{\mathbf{3}}\mathbf{\left(}\mathbf{l}\mathbf{\right)}\mathbf{+}\mathbf{NO}\mathbf{\left(}\mathbf{g}\mathbf{\right)}$      

(a) What are the oxidizing and reducing agents in each step?

(b) Assuming 100% yield in each step, what mass (in kg) of ammonia must be used to produce 3.0 X 10⁴ kg of HNO₃?

For the following aqueous reactions, complete and balance the molecular equation and write a net ionic equation:

(a) Manganese(II) sulfide + hydrobromic acid

(b) Potassium carbonate + strontium nitrate

(c) Potassium nitrite + hydrochloric acid

(d) Calcium hydroxide + nitric acid

(e) Barium acetate + iron(II) sulfate

(f) Zinc carbonate + sulfuric acid

(g) Copper(II) nitrate + hydrosulfuric acid

(h) Magnesium hydroxide + chloric acid

(i) Potassium chloride + ammonium phosphate

(j) Barium hydroxide + hydrocyanic acid

There are various methods for finding the composition of an alloy (a metal-like mixture). Show that calculating the mass % of Mg in a magnesium-aluminum alloy (d = 2.40 g/cm³) gives the same answer (within rounding) using each of these methods: 

(a) $\mathbf{a}\mathbf{ }\mathbf{0}\mathbf{.}\mathbf{263}\mathbf{-}\mathbf{gsample}\mathbf{ }\mathbf{of}\mathbf{ }\mathbf{alloy}(\mathbf{d}\mathbf{ }\mathbf{of}\mathbf{ }\mathbf{Mg}\mathbf{=}\mathbf{1}\mathbf{.}\mathbf{74}\mathbf{g}\mathbf{/}{\mathbf{cm}}^3\mathbf{;}\mathbf{dofAl}\mathbf{=}\mathbf{2}\mathbf{.}\mathbf{70}\mathbf{g}\mathbf{/}{\mathbf{cm}}^3)\mathbf{;}$   

(b) an identical sample reacting with excess aqueous HCl forms  $\mathbf{1}\mathbf{.}\mathbf{38}\mathbf{x}{\mathbf{10}}^{-2}\mathbf{mol}\mathbf{ }\mathbf{of}\mathbf{ }{\mathbf{H}}_2\mathbf{;}$ 

(c)  an identical sample reacting with excess O₂  forms 0.483 g of oxide.

Use the oxidation number method to balance the following equations by placing coefficients in the blanks. Identify the reducing and oxidizing agents:

 $\begin{array}{l}\mathbf{\left(}\mathbf{a}\mathbf{\right)}\mathbf{\_}\mathbf{KOH}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}\mathbf{\_}{\mathbf{H}}_{\mathbf{2}}{\mathbf{O}}_{\mathbf{2}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}\mathbf{\_}\mathbf{Cr}{\mathbf{\left(}\mathbf{OH}\mathbf{\right)}}_{\mathbf{3}}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{\to }\mathbf{\_}{\mathbf{K}}_{{}_{\mathbf{2}}}{\mathbf{CrO}}_{\mathbf{4}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}\mathbf{\_}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{\left(}\mathbf{l}\mathbf{\right)}\\ \mathbf{\left(}\mathbf{b}\mathbf{\right)}\mathbf{\_}{\mathbf{MnO}}_{\mathbf{4}}^{\mathbf{-}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}\mathbf{\_}{\mathbf{ClO}}_{\mathbf{2}}^{\mathbf{-}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}\mathbf{\_}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{\left(}\mathbf{l}\mathbf{\right)}\mathbf{\to }\mathbf{\_}{\mathbf{MnO}}_{\mathbf{2}}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{+}\mathbf{\_}{\mathbf{ClO}}_{\mathbf{4}}^{\mathbf{-}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}{\mathbf{OH}}^{\mathbf{-}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\\ \mathbf{\left(}\mathbf{c}\mathbf{\right)}\mathbf{\_}{\mathbf{KMnO}}_{\mathbf{4}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}\mathbf{\_}{\mathbf{Na}}_{\mathbf{2}}{\mathbf{SO}}_{\mathbf{3}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}\mathbf{\_}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{\left(}\mathbf{l}\mathbf{\right)}\mathbf{\to }\mathbf{\_}{\mathbf{MnO}}_{\mathbf{2}}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{+}\mathbf{\_}{\mathbf{Na}}_{\mathbf{2}}{\mathbf{SO}}_{\mathbf{4}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}\mathbf{\_}\mathbf{KOH}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\\ \mathbf{\left(}\mathbf{d}\mathbf{\right)}\mathbf{\_}{\mathbf{CrO}}_{\mathbf{4}}^{\mathbf{2}\mathbf{-}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}\mathbf{\_}{\mathbf{HSnO}}_{\mathbf{2}}^{\mathbf{-}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}\mathbf{\_}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{\left(}\mathbf{l}\mathbf{\right)}\mathbf{\to }\mathbf{\_}{{\mathbf{CrO}}_{\mathbf{2}}}^{\mathbf{-}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}\mathbf{\_}{\mathbf{HSnO}}_{\mathbf{3}}^{\mathbf{-}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}{\mathbf{OH}}^{\mathbf{-}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\\ \mathbf{\left(}\mathbf{e}\mathbf{\right)}\mathbf{\_}{\mathbf{KMnO}}_{\mathbf{4}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}\mathbf{\_}{\mathbf{NaNO}}_{\mathbf{2}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}\mathbf{\_}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{\left(}\mathbf{l}\mathbf{\right)}\mathbf{\to }\mathbf{\_}{\mathbf{MnO}}_{\mathbf{2}}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{+}\mathbf{\_}{\mathbf{NaNO}}_{\mathbf{3}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}\mathbf{\_}\mathbf{KOH}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\\ \mathbf{\left(}\mathbf{f}\mathbf{\right)}\mathbf{\_}{\mathbf{I}}^{\mathbf{-}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\mathbf{+}\mathbf{\_}{\mathbf{O}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{+}\mathbf{\_}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}\mathbf{\left(}\mathbf{l}\mathbf{\right)}\mathbf{\to }\mathbf{\_}{\mathbf{I}}_{\mathbf{2}}\mathbf{\left(}\mathbf{s}\mathbf{\right)}\mathbf{+}\mathbf{\_}{\mathbf{OH}}^{\mathbf{-}}\mathbf{\left(}\mathbf{aq}\mathbf{\right)}\end{array}$

In 1995, Mario Molina, Paul Crutzen, and F. Sherwood Rowland shared the Nobel Prize in chemistry for their work on atmospheric chemistry. One of several reaction sequences proposed for the role of chlorine in the decomposition of stratospheric ozone (we’ll see another sequence in Chapter 16) is

 $\begin{array}{l}\mathbf{\left(}\mathbf{1}\mathbf{\right)}\mathbf{Cl}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{+}{\mathbf{O}}_{\mathbf{3}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{\to }\mathbf{ClO}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{+}{\mathbf{O}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\\ \mathbf{\left(}\mathbf{2}\mathbf{\right)}\mathbf{ClO}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{+}\mathbf{ClO}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{\to }{\mathbf{Cl}}_{\mathbf{2}}{\mathbf{O}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\\ \mathbf{\left(}\mathbf{3}\mathbf{\right)}{\mathbf{Cl}}_{\mathbf{2}}{\mathbf{O}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\stackrel{\mathbf{light}}{\mathbf{\to }}\mathbf{2}\mathbf{Cl}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{+}{\mathbf{O}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\end{array}$

Over the tropics, O atoms are more common in the stratosphere:

 $\mathbf{\left(}\mathbf{4}\mathbf{\right)}\mathbf{ClO}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{+}\mathbf{O}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{\to }\mathbf{Cl}\mathbf{\left(}\mathbf{g}\mathbf{\right)}\mathbf{+}{\mathbf{O}}_{\mathbf{2}}\mathbf{\left(}\mathbf{g}\mathbf{\right)}$

(a) Which, if any, of these are oxidation-reduction reactions?

(b) Write an overall equation combining reactions 1–3.