Liquid hydrazine, N2H4, has been used as a fuel for rockets. When the rocket is to be launched, a catalyst causes the liquid hydrazine to decompose quickly into elemental nitrogen and hydrogen gases. The rapid expansion of the product gases and the heat released by the reaction provide the thrust for the rocket. Write the unbalanced equation for the reaction of hydrazine to produce nitrogen and hydrogen gases.
> Name each of the following acids. a. HCl b. H2SO4 c. HNO3 d. HI e. HNO2 f. HClO3 g. HBr h. HF i. HC2H3O2
> Many acids contain the element in addition to hydrogen.
> Give a simple definition of an acid.
> Name each of the following compounds, which contain polyatomic ions. a. NaMnO4 b. AlPO4 c. CrCO3 d. Ca(ClO)2 e. BaCO3 f. CaCrO4
> Name each of the following compounds, which contain polyatomic ions. a. NH4NO3 b. Ca(HCO3)2 c. MgSO4 d. Na2HPO4 e. KClO4 f. Ba(C2H3O2)2
> Give the name of each of the following polyatomic ions. a. NH4+ b. H2PO4- c. SO42- d. HSO3- e. ClO4- f. IO3-
> Give the name of each of the following polyatomic ions. a. HCO3- b. C2H3O2- c. CN- d. OH- e. NO2- f. HPO42-
> Carbon occurs in several common polyatomic anions. List the formulas of as many such anions as you can, along with the names of the anions.
> Write the formulas for the following compounds (refer to your answers to Problem 30). a. sodium cyanide b. calcium carbonate c. potassium hydrogen carbonate d. magnesium acetate
> Write the formula for each of the following carbon-containing ions, including the overall charge of the ion. a. cyanide b. carbonate c. hydrogen carbonate d. acetate
> Cations are ions, and anions are ions.
> Write the formula for each of the following phosphorus- containing ions, including the overall charge of the ion. a. phosphide b. phosphate c. phosphite d. hydrogen phosphate
> A series of oxyanions of iodine, comparable to the series for chlorine discussed in the text, also exists. Write the formulas and names for the oxyanions of iodine.
> Complete the following list by filling in the missing names or formulas of the oxyanions of chlorine. CIO,- hypochlorite CIO,- chlorite
> In naming oxyanions, when there are more than two members in the series for a given element, what prefixes are used to indicate the oxyanions in the series with the fewest and the most oxygen atoms?
> For the oxyanions of sulfur, the ending -ite is used for SO32- to indicate that it contains than does SO42-.
> A(n) is a polyatomic ion containing at least one oxygen atom and one or more atoms of at least one other element.
> What is a polyatomic ion? Give examples of five common polyatomic ions.
> Name each of the following binary compounds, using the periodic table to determine whether the compound is likely to be ionic (containing a metal or a nonmetal) or nonionic (containing only nonmetals). a. RaCl2 b. SeCl2 c. PCl3 d. Na3P e. MnF2 f. Z
> Name each of the following binary compounds, using the periodic table to determine whether the compound is likely to be ionic (containing a metal and a nonmetal) or nonionic (containing only nonmetals). a. MgS b. AlCl3 c. PH3 d. ClBr e. Li2O f. P4O
> Many over-the-counter antacid tablets are now formulated using calcium carbonate as the active ingredient, which enables such tablets to also be used as dietary calcium supplements. As an antacid for gastric hyperacidity, calcium carbonate reacts by comb
> What is a binary chemical compound? What are the two major types of binary chemical compounds? Give three examples of each type of binary compound.
> Name each of the following binary compounds, using the periodic table to determine whether the compound is likely to be ionic (containing a metal and a nonmetal) or nonionic (containing only nonmetals). a. Fe3P2 b. CaBr2 c. N2O5 d. PbCl4 e. S2F10 f
> What is meant by a strong electrolyte? Give two examples of substances that behave in solution as strong electrolytes.
> When the ionic solute K3PO4 is dissolved in water, what can you say about the number of potassium ions (K+) present in the solution compared with the number of phosphate ions (PO43-) in the solution?
> Reactions involving the combustion of fuel substances make up a subclass of reactions.
> How do we define a combustion reaction? In addition to the chemical products, what other products do combustion reactions produce? Give two examples of balanced chemical equations for combustion reactions.
> Silver oxide may be decomposed by strong heating into silver metal and oxygen gas. Write the unbalanced chemical equation for this process.
> For the reaction 2Na(s) + O2(g) Na2O2(s), show how electrons are gained and lost by the atoms.
> For the reaction Mg(s) + Cl2(g) MgCl2(s), illustrate how electrons are gained and lost during the reaction.
> If oxygen molecules, O2, were to react with magnesium atoms, how many electrons would each magnesium atom lose? How many electrons would each oxygen atom gain? How many magnesium atoms would be needed to react with each oxygen molecule? What charges woul
> If atoms of the metal calcium were to react with molecules of the nonmetal fluorine, F2, how many electrons would each calcium atom lose? How many electrons would each fluorine atom gain? How many calcium atoms would be needed to react with one fluorine
> The thermite reaction produces so much energy (heat) that the iron is initially formed as a liquid. 2Al(s) + Fe2O3(s) 2Fe(s) + Al2O3(s) Describe the transfer of electrons for both the aluminum and iron.
> Give an example of a simple chemical reaction that involves the transfer of electrons from a metallic element to a nonmetallic element.
> What is an oxidation–reduction reaction? What is transferred during such a reaction?
> When writing the chemical equation for a reaction, how do you indicate that a given reactant is dissolved in water? How do you indicate that a precipitate has formed as a result of the reaction?
> Along with the three strong acids emphasized in the chapter (HCl, HNO3, and H2SO4), hydrobromic acid, HBr, and perchloric acid, HClO4, are also strong acids. Write equations for the dissociation of each of these additional strong acids in water.
> Write balanced equations showing how three of the common strong acids ionize to produce hydrogen ion.
> If electricity of sufficient voltage is passed into a solution of potassium iodide in water, a reaction takes place in which elemental hydrogen gas and elemental iodine are produced, leaving a solution of potassium hydroxide. Write the unbalanced equatio
> What is a salt? Give two balanced chemical equations showing how a salt is formed when an acid reacts with a base.
> If 1000 NaOH units were dissolved in a sample of water, the NaOH would produce Na1 ions and OH2 ions.
> Write the formulas and names of three common strong acids and strong bases.
> The same net ionic process takes place when any strong acid reacts with any strong base. Write the equation for that process.
> What is meant by a strong base? Are the strong bases also strong electrolytes? Explain.
> What is meant by a strong acid? Are the strong acids also strong electrolytes? Explain.
> Another step in the qualitative analysis of cations (see Exercise 28) involves precipitating some of the metal ions as the insoluble sulfides (followed by subsequent treatment of the mixed sulfide precipitate to separate the individual ions). Write balan
> A reaction in aqueous solution that results in the formation of a solid is called a reaction.
> Many plants are poisonous because their stems and leaves contain oxalic acid, H2C2O4, or sodium oxalate, Na2C2O4; when ingested, these substances cause swelling of the respiratory tract and suffocation. A standard analysis for determining the amount of o
> The procedures and principles of qualitative analysis are covered in many introductory chemistry laboratory courses. In qualitative analysis, students learn to analyze mixtures of the common positive and negative ions, separating and confirming the prese
> Many chromate (CrO42-) salts are insoluble, and most have brilliant colors that have led to their being used as pigments. Write balanced net ionic equations for the reactions of Cu2+, Co3+, Ba2+, and Fe3+ with chromate ion.
> Write the balanced molecular, complete ionic, and net ionic equations for the reaction between nickel(II) chloride and sodium sulfide.
> Which of the following most accurately describes a spectator ion? a. An ion that is used up in a chemical reaction; it is limiting. b. An ion that participates in a chemical reaction but is always present in excess c. An ion that becomes part of the p
> A solution of zinc nitrate is mixed with a solution of potassium hydroxide. A precipitate forms. Complete and balance the equation for this reaction, including the phases of each reactant and product.
> What is a “driving force”? What are some of the driving forces discussed in this section that tend to make reactions likely to occur? Can you think of any other possible driving forces?
> On the basis of the general solubility rules given in Table 7.1, for each of the following compounds, explain why the compound would not be expected to be appreciably soluble in water. Indicate which of the solubility rules covers each substance’s partic
> On the basis of the general solubility rules given in Table 7.1, for each of the following compounds, explain why the compound would be expected to be appreciably soluble in water. Indicate which of the solubility rules covers each substanceâ€
> Using the general solubility rules given in Table 7.1, which of the following ions will form a precipitate with SO42-? a. Ba2+ b. Na+ c. NH4+ d. At least two of the above ions will form a precipitate with SO42-. e. All of the above ions will form a
> In a chemical reaction, the total number of atoms present after the reaction is complete is (larger than/smaller than/the same as) the total number of atoms present before the reaction began.
> For the unbalanced chemical equation HCl(g) + O2(g) H2O(g) + Cl2(g) a. list the reactant(s). b. list the product(s).
> If a sample of pure hydrogen gas is ignited very carefully, the hydrogen burns gently, combining with the oxygen gas of the air to form water vapor. Write the unbalanced chemical equation for this reaction.
> Balance the following chemical equations. MnO2(s) + CO(g) Mn2O3(aq) + CO2(g) Al(s) + H2SO4(aq) Al2(SO4)3(aq) + H2(g) C4H10(g) + O2(g) CO2(g) + H2O(l) NH4I(aq) + Cl2(g)
> Using different shapes to distinguish between different elements, draw a balanced equation for the following reaction at the microscopic level. NH3(g) + O2(g) NO(g) + H2O(g)
> Balance the following chemical equation: CuSO4(aq) + KI(s) CuI(s) + I2(s) + K2SO4(aq)
> Which of the following statements about chemical reactions is false? a. When balancing a chemical equation, all subscripts must be conserved. b. When one coefficient is doubled, the rest of the coefficients in the balanced equation must also be doubled
> When lead(II) sulfide is heated to high temperatures in a stream of pure oxygen gas, solid lead(II) oxide forms with the release of gaseous sulfur dioxide. Write the unbalanced chemical equation for this reaction.
> When copper(II) oxide is boiled in an aqueous solution of sulfuric acid, a strikingly blue solution of copper(II) sulfate forms along with additional water. Write the unbalanced chemical equation for this reaction.
> What are the substances to the left of the arrow in a chemical equation called? To the right of the arrow? What does the arrow itself mean?
> When solid red phosphorus, P4, is burned in air, the phosphorus combines with oxygen, producing a choking cloud of tetraphosphorus decoxide. Write the unbalanced chemical equation for this reaction.
> Which of the following statements is false for the reaction of hydrogen gas with oxygen gas to produce water? (a, b, and c represent coefficients) a H2(g) + b O2(g) c H2O(g) a. The ratio of “ayc” must always equal one. b. The sum o
> When a strip of magnesium metal is heated in oxygen, it bursts into an intensely white flame and produces a finely powdered dust of magnesium oxide. Write the unbalanced chemical equation for this process.
> A common lecture demonstration called “elephant’s toothpaste” demonstrates the reaction of hydrogen peroxide producing water and oxygen gas. Write the unbalanced chemical equation for this process.
> When finely divided solid sodium is dropped into a flask containing chlorine gas, an explosion occurs and a fine powder of sodium chloride is deposited on the walls of the flask. Write the unbalanced chemical equation for this process.
> When iron wire is heated in the presence of sulfur, the iron soon begins to glow, and a chunky, blue-black mass of iron(II) sulfide is formed. Write the unbalanced chemical equation for this reaction.
> If you had a “sour stomach,” you might try an over-the-counter antacid tablet to relieve the problem. Can you think of evidence that the action of such an antacid is a chemical reaction?
> Balance the following chemical equation. LiAlH4(s) + AlCl3(s) AlH3(s) + LiCl(s)
> If you’ve ever left bread in a toaster too long, you know that the bread eventually burns and turns black. What evidence is there that this represents a chemical process?
> Glass is a mixture of several compounds, but a major constituent of most glass is calcium silicate, CaSiO3. Glass can be etched by treatment with hydrogen fluoride: HF attacks the calcium silicate of the glass, producing gaseous and water-soluble product
> Write a balanced chemical equation for the complete combustion of pentene, C7H14. In combustion, pentene reacts with oxygen to produce carbon dioxide and water.
> A common demonstration in chemistry courses involves adding a tiny speck of manganese(IV) oxide to a concentrated hydrogen peroxide, H2O2, solution. Hydrogen peroxide is unstable, and it decomposes quite spectacularly under these conditions to produce ox
> A common experiment in introductory chemistry courses involves heating a weighed mixture of potassium chlorate, KClO3, and potassium chloride. Potassium chlorate decomposes when heated, producing potassium chloride and evolving oxygen gas. By measuring t
> When elemental boron, B, is burned in oxygen gas, the product is diboron trioxide. If the diboron trioxide is then reacted with a measured quantity of water, it reacts with the water to form what is commonly known as boric acid, B(OH)3. Write a balanced
> A common experiment to determine the relative reactivity of metallic elements is to place a pure sample of one metal into an aqueous solution of a compound of another metallic element. If the pure metal you are adding is more reactive than the metallic
> One method of producing hydrogen peroxide is to add barium peroxide to water. A precipitate of barium oxide forms, which may then be filtered off to leave a solution of hydrogen peroxide. Write the balanced chemical equation for this process.
> When steel wool (iron) is heated in pure oxygen gas, the steel wool bursts into flame and a fine powder consisting of a mixture of iron oxides (FeO and Fe2O3) forms. Write separate unbalanced equations for the reaction of iron with oxygen to give each of
> Iron oxide ores, commonly a mixture of FeO and Fe2O3, are given the general formula Fe3O4. They yield elemental iron when heated to a very high temperature with either carbon monoxide or elemental hydrogen. Balance the following equations for these proce
> The Hall process is an important method by which pure aluminum is prepared from its oxide (alumina, Al2O3) by indirect reaction with graphite (carbon). Balance the following equation, which is a simplified representation of this process. Al2O3(s) + C(s)
> You have probably had the unpleasant experience of discovering that a flashlight battery has gotten old and begun to leak. Is there evidence that this change is due to a chemical reaction?
> Methanol (methyl alcohol), CH3OH, is a very important industrial chemical. Formerly, methanol was prepared by heating wood to high temperatures in the absence of air. The complex compounds present in wood are degraded by this process into a charcoal resi
> The following demonstration takes place in a two-step process: First, solid calcium carbide (CaC2) reacts with liquid water to produce acetylene gas (C2H2) and aqueous calcium hydroxide. Second, the acetylene gas produced is then ignited with a match, ca
> Crude gunpowders often contain a mixture of potassium nitrate and charcoal (carbon). When such a mixture is heated until reaction occurs, a solid residue of potassium carbonate is produced. The explosive force of the gunpowder comes from the fact that tw
> When balancing a chemical equation, which of the following statements is false? a. Subscripts in the reactants must be conserved in the products. b. Coefficients are used to balance the atoms on both sides. c. The law of conservation of matter must be
> Acetylene gas, C2H2, is used in welding because it generates an extremely hot flame when it is combusted with oxygen. The heat generated is sufficient to melt the metals being welded together. Carbon dioxide gas and water vapor are the chemical products
> In each of the following, identify which names are incorrect for the given formulas, and give the correct name. a. CuCl2, copper(I) chloride b. Ag2O, silver oxide c. Li2O, lithium oxide d. CaS, calcium(II) sulfide e. Cs2S, cesium sulfide
> Although this is no longer generally recommended, in the past, small cuts and abrasions on the skin were frequently cleaned using hydrogen peroxide solution. What evidence is there that treating a wound with hydrogen peroxide causes a chemical reaction t
> Balance the equation for the reaction of potassium with water. K(s) + H2O(l) H2(g) + KOH(aq) Aichard Megna/Fundamental Photographs © Cengage Learming
> The “Chemistry in Focus” segment The Beetle That Shoots Straight discusses the bombardier beetle and the chemical reaction of the decomposition of hydrogen peroxide. H2O2 (aq) H2O(l) + O2 (g) The balanced equation given in the s
> When balancing chemical equations, beginning students are often tempted to change the numbers within a formula (the subscripts) to balance the equation. Why is this never permitted? What effect does changing a subscript have?
> Nitric acid, HNO3, can be produced by reacting high-pressure ammonia gas with oxygen gas at around 750 °C in the presence of a platinum catalyst. Water is a by-product of the reaction. Write the unbalanced chemical equation for this process.
> The element tin often occurs in nature as the oxide, SnO2. To produce pure tin metal from this sort of tin ore, the ore usually is heated with coal (carbon). This produces pure molten tin, with the carbon being removed from the reaction system as the gas
> Although they were formerly called the inert gases, the heavier elements of Group 8 do form relatively stable compounds. For example, at high temperatures in the presence of an appropriate catalyst, xenon gas will combine directly with fluorine gas to pr
