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All Textbook Solutions for Introductory Chemistry: A Foundation

5CR What is meant by anuclear atom? Describe the points of Ruth erford’s model for the nuclear atom and how he tested this model. Based on his experiments, how did Rutherford envision the structure of the atom? How did Rutherford’s model of the atom’s structure differ from Kelvin’s “plum pudding” model?7CR 8CR 9CR Are most elements found in nature in the elemental or the combined form? Why? Name several elements that are usually found in the elemental form.What are bus? How are ions formed from atoms? Do isolated atoms form ions spontaneously? To what do the termscationandanionrefer? In terms of subatomic particles, how is an ion related to the atom from which it is formed? Does the nucleus of an atom change when the atom is converted into an ion? How can the periodic table be used to predict what ion an element’s atoms will form?12CR 13CR 14CR 15CR 16CR 17CR 18CR 19CR 20CR 21CR How many electrons, protons, and neutrons are found in isolated atoms having the following atomic symbols? a.817Oe.24He b.92235Uc.50119Sn c.1737Clg.54119Xe d.13Hh.3064Zn What simple ion does each of the following elements most commonly form? a. Sr f. O j. Mg b. I g. Rbk. S c. Ag h. N l. P d. Al i. K m. Cl e. Se 24CR 25CR 26CR 27CR 28CR 29CR 30CR 31CR 6.1SC 1CT One part of the problem-solving strategy for balancing chemical equations is “starting with the most complicated molecule.” What if you started with a different molecule? Could you still eventually balance the chemical equation? How would this approach be different from the suggested technique?6.2SC 6.3SC The following are actual student responses to the question: Why is it necessary to balance chemical equations? The chemicals will not react until you have added the correct ratios. The correct products will not form unless the right amounts of reactants have been added. A certain number of products cannot form without a certain number of reactants. The balanced equation tells you how much reactant you need, and allows you to predict how much product you will make. A ratio must be established for the reaction to occur as written. Justify the best choice, and, for choices you did not pick, explain what is wrong with them.2ALQ Given the equation for the reaction:N2+H2NH3 , draw a molecular diagram that represents the reaction (make sure it is balanced).4ALQ Can the subscripts in a chemical formula be fractions? Explain.6ALQ Changing the subscripts of chemicals can mathematically balance the equations. Why is this unacceptable?Table 6.1 lists some clues that a chemical reaction has occurred. However, these events do not necessarily prove the existence of a chemical change. Give an example for each of the clues that is not a chemical reaction but a physical change.Use molecular-level drawings to show the difference between physical and chemical changes.It is stated in Section 6.3 of the text that to balance equations by inspection you start “with the most complicated molecule.” What does this mean? Why is it best to do this?11ALQ Consider the generic chemical equationaA+bBcC+dD (where a, b, c, and d represent coefficients for the chemicals A, B, C, and D, respectively). a. How many possible values are there for “c”? Explain your answer. b. How many possible values are there for “c/d”? Explain your answer.13ALQ Which of the following correctly describes the balanced chemical equation given below? There may be more than one true statement. If a statement is incorrect, explain why it is incorrect. m:math>4Al+3O22Al2O3 l type='a'> For every 4 atoms of aluminum that reacts with 6 atoms of oxygen, 2 molecules of aluminum oxide are produced. i>For every 4 moles of aluminum that reacts with 3 moles of oxygen, 2 moles of aluminum(III) oxide are produced. i>For every 4 g of aluminum that reacts with 3 g of oxygen, 2 g of aluminum oxide are produced.Which of the following correctly balances the chemical equation given below? There may be more than one correct balanced equation. If a balanced equation is incorrect, explain why it is incorrect. m:math>CaO+CCaC2+CO2 msp;CaO2+3CCaC2+CO2 msp;2CaO+5C2CaC2+CO2 msp;CaO+212CCaC2+12CO2 msp;4CaO+10C4CaC2+2CO2 The reaction of an element X() with element Y() is represented in the following diagram. Which of the elements bestdescribes this reaction? mg src=Images/HTML_99425-6-16ALQ_image001.jpg alt="" align="top"/> msp;3X+6YX3Y8 msp;3X+6YX3Y6 msp;X+2YXY2 msp;3X+8Y3XY2+2Y 1QAP 2QAP Although these days many people have “self-cleaning” ovens, if your oven getsreallydirty you may have to resort to one of the spray-on oven cleaner preparations sold in supermarkets. What evidence is there that such oven cleaners work by a chemical reaction?4QAP 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?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?What are the substances to theleftof the arrow in a chemical equation called? To therightof the arrow? What does the arrow itself mean?8QAP 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.10QAP 11QAP The notation “(l)” after a substance’s formula indicates it exists in the __________ state.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 element in the compound, then the pure metal willreplacethe metallic element in the compound. For example. if you place a piece of pure zinc metal into a solution of copper(II) sulfate, the zinc will slowly dissolve to produce zinc sulfate solution, and the copper(II) ion of the copper(II) sulfate will be converted to metallic copper. Write the unbalanced equation for this process.If calcium carbonate is heated strongly, carbon dioxide gas is driven off. leaving a residue of calcium oxide. Write the unbalanced chemical equation for this process.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.Liquid hydrazine, 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.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 equation for this process.Silver oxide may be decomposed by strong heating into silver metal and oxygen gas. Write the unbalanced chemical equation for this process.Elemental boron is produced in one industrial process by heating diboron trioxide with magnesium metal, also producing magnesium oxide as a by-product. Write the unbalanced chemical equation for this process.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 combining with hydrochloric acid found in the stomach, producing a solution of calcium chloride, converting the stomach acid to water, and releasing carbon dioxide gas (which the person suffering from stomach problems may feel as a “burp”). Write the unbalanced chemical equation for this process.Phosphorus trichloride is used in the manufacture of certain pesticides and may be synthesized by direct combination of its constituent elements. Write the unbalanced chemical equation for this process.Pure silicon, which is needed in the manufacturing of electronic components, may be prepared by heating silicon dioxide (sand) with carbon at high temperatures, releasing carbon monoxide gas. Write the unbalanced chemical equation for this process.Nitrous oxide gas (systematic name: dinitrogen monoxide) is used by some dental practitioners as an anesthetic. Nitrous oxide (and water vapor as by-product) can be produced in small quantities in the laboratory by careful heating of ammonium nitrate. Write the unbalanced chemical equation for this reaction.Solid zinc is added to an aqueous solution containing dissolved hydrogen chloride to produce gaseous hydrogen that hubbies out of the solution and zinc chloride that remains dissolved in the water. Write the unbalanced chemical equation for this process. mg src=Images/HTML_99425-6-24QAP_image001.jpg alt="" align="top"/>Acetylene gas (C2H2) is often used by plumbers, welders, and glass blowers because it burns in oxygen with an intensely hot flame. The products of the combustion of acetylene are carbon dioxide and water vapor. Write the unbalanced chemical equation for this process.The burning of high-sulfur fuels has been shown to cause the phenomenon of “acid rain.” When a high-sulfur fuel is burned, the sulfur is converted to sulfur dioxide (SO2) and sulfur trioxide (SO3) . When sulfur dioxide and sulfur trioxide gas dissolve in water in the atmosphere, sulfurous acid and sulfuric acid are produced, respectively. Write the unbalanced chemical equations for the reactions of sulfur dioxide and sulfur trioxide with water.The Group 2 metals (Ba, Ca, Sr) can be produced in the elemental state by the reaction of their oxides with aluminum metal at high temperatures, also producing solid aluminum oxide as a by-product. Write the unbalanced chemical equations for the reactions of barium oxide, calcium oxide, and strontium oxide with aluminum.There are fears that the protective ozone layer around the earth is being depleted. Ozone, is produced by the interaction of ordinary oxygen gas in the atmosphere with ultraviolet light and lightning discharges. The oxides of nitrogen (which are common in automobile exhaust gases), in particular, are known to decompose ozone. For example, gaseous nitric oxide (NO) reacts with ozone gas to produce nitrogen dioxide gas and oxygen gas. Write the unbalanced chemical equation for this process.Carbon tetrachloride was widely used for many years as a solvent until its harmful properties became well established. Carbon tetrachloride may be prepared by the reaction of natural gas (methane, CH4 ) and elemental chlorine gas in the presence of ultraviolet light. Write the unbalanced chemical equation for this process.When elemental phosphorus, P4, burns in oxygen gas, it produces an intensely bright light, a great deal of heat, and massive clouds of white solid phosphorus(V) oxide (P2O5) product. Given these properties, it is not surprising that phosphorus has been used to manufacture incendiary bombs for warfare. Write the unbalanced equation for the reaction of phosphorus with oxygen gas to produce phosphorus(V) oxide.Calcium oxide is sometimes very challenging to store in the chemistry laboratory. This compound reacts with moisture in the air and is converted to calcium hydroxide. If a bottle of calcium oxide is left on the shelf too long, it gradually absorbs moisture from the humidity in the laboratory. Eventually the bottle cracks and spills the calcium hydroxide that has been produced. Write the unbalanced chemical equation for this process.32QAP 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 gaseous byproduct carbon monoxide. Write the unbalanced equation for this process.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.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?The “Chemistry in Focus” segment The Beetle That Shoots Straight discusses the bombardier beetle and the chemical reaction of the decomposition of hydrogen peroxide. m:math>H2O2(aq)H2O(l)+O2(g) e balanced equation given in the segment is m:math>2H2O2(aq)2H2O(l)+O2(g) y can’t we balance the equation in the following way? m:math>H2O2(aq)H2(g)+O2(g) e molecular-level pictures like those in Section 6.3 to support your answer.Balance each of the following chemical equations. l type='a'> msp;FeCl3(aq)+KOH(aq)Fe(OH)3(s)+KCl(aq) i>Pb(C2H3O2)2(aq)+KI(aq)PbI2(s)+KC2H3O2(aq) i>P4O10(s)+H2O(l)H3PO4(aq) i>Li2O(s)+H2O(l)LiOH(aq) i>MnO2(s)+C(s)Mn(s)+CO2(g) i>Sb(s)+Cl2(g)SbCl3(s) i>CH4(g)+H2O(g)CO(g)+H2(g) i>FeS(s)+HCl(aq)FeCl2(aq)+H2S(g)Balance the equations for the reaction of potassium with water. :math>K(s)+H2(l)H2(g)+KOH(aq) mg src=Images/HTML_99425-6-38QAP_image001.jpg alt="" align="top"/>Balance each of the following chemical equations. msp;K2SO4(aq)+BaCl2(aq)BaSO4(s)+KCl(aq) msp;Fe(s)+H2O(g)FeO(s)+H2(g) msp;NaOH(aq)+HClO4(aq)NaCIO4(aq)+H2O(l) msp;Mg(s)+Mn2O3(s)MgO(s)+Mn(s) msp;KOH(s)+KH2PO4(aq)K3PO4(aq)+H2O(l) msp;NO2(g)+H2O(l)+O2(g)HNO3(aq) msp;BaO2(s)+H2O(l)Ba(OH)2(aq)+O2(g) msp;NH3(g)+O2(g)NO(g)+H2O(l)Balance each of the following chemical equations. msp;Na2SO4(aq)+CaCl2(aq)CaSO4(s)+NaCl(aq) msp;Fe(s)+H2O(g)Fe3O4(s)+H2(g) msp;Ca(OH)2(aq)+HCl(aq)CaCl2(aq)+H2O(l) msp;Br2(g)+H2O(l)+SO2(g)HBr(aq)+H2SO4(aq) msp;NaOH(s)+H3PO4(aq)Na3PO4(aq)+H2O(l) msp;Na2O2(s)+H2O(l)NaOH(aq)+O2(g) msp;Si(s)+S8(s)Si2S4(s)Balance each of the following chemical equations. l type='a'> msp;Fe3O4(s)+H2(g)Fe(l)+H2O(g) i>K2SO4(aq)+BaCl2(aq)BaSO4(s)+KCl(aq) i>HCl(aq)+FeS(s)FeCl2(aq)+H2S(g) i>Br2(g)+H2O(l)+SO2(g)HBr(aq)+H2SO4(aq) i>CS2(l)+Cl2(g)CCl4(l)+S2Cl2(g) i>Cl2O7(g)+Ca(OH)2(aq)Ca( ClO4)2(aq)+H2O(l) i>PBr3(l)+H2O(l)H3PO3(aq)+HBr(g) i>Ba( ClO3)2(s)BaCl2(s)+O2(s) mg src=Images/HTML_99425-6-41QAP_image001.jpg alt="" align="top"/>42QAP 43QAP 44QAP 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 of this reaction. Write the unbalanced chemical equation for the reaction of acetylene with oxygen.When balancing a chemical equation, which of the following statements is false? l type='a'> Subscripts in the reactants must be conserved in the products. i>Coefficients are used to balance the atoms on both sides. i>The law of conservation of matter must he followed. i>Phases are often shown for each compound hut are not critical to balancing an equation.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 two gases are also produced (carbon monoxide and nitrogen), which increase in volume with great force and speed. Write the unbalanced chemical equation for the process.48AP 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 residue and a volatile portion that is rich in methanol. Today, methanol is instead synthesized from carbon monoxide and elemental hydrogen. Write the balanced chemical equation for this latter process.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. m:math>Al2O3(s)+C(s)Al(s)+CO2(g)Iron oxide ores, commonly a mixture of FeO and Fe2O3 , are given the general formula Fe2O3 . They yield elemental iron when heated to a very high temperature with either carbon monoxide or elemental hydrogen. Balance the following equations for these processes. m:math>Fe2O4(s)+H2(g)Fe(s)+H2O(g)Fe2O4(s)+CO(g)Fe(s)+CO2(g)True or false? Coefficients can be fractions when balancing a chemical equation. Whether true or false, explain why this can or cannot occur.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 these products.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 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 chemical equation for each of these processes.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 the volume of oxygen gas produced in this experiment, students can calculate the relative percentage of KClO3 and KCl in the original mixture. Write the balanced chemical equation for this process.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 oxygen gas and steam (water vapor). Manganese(IV) oxide is a catalyst for the decomposition of hydrogen peroxide and is not consumed in the reaction. Write the balanced equation for the decomposition reaction of hydrogen peroxide.58AP 59AP 60AP 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?When iron wire is heated in the presence of sulfur, the iron sulfur begins to glow, and a chunky, blue-black mass of iron (II) sulfide is formed. Write the unbalanced chemical equation for this reaction.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 wails of the flask. Write the unbalanced chemical equation for this process.If aqueous solutions of potassium chromate and barium chloride are mixed, a bright yellow solid (barium chromate) forms and settles out of the mixture, leaving potassium chloride in solution. Write a balanced chemical equation for this process.When hydrogen sulfide, H2S , gas is bubbled through a solution of lead(II) nitrate, Pb( NO3)2 , a black precipitate of lead(II) sulfide, PbS. forms, and nitric acid, HNO3 , is produced. Write the unbalanced chemical equation for this reaction.If an electric current is passed through aqueous solutions of sodium chloride, sodium bromide, and sodium iodide, the elemental halogens are produced at one electrode in each case, with hydrogen gas being evolved at the other electrode. If the liquid is then evaporated from the mixture, a residue of sodium hydroxide remains. Write balanced chemical equations for these electrolysis reactions.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.68AP When solid red phosphorus, is burned in air, the phosphorus combines with oxygen, producing a choking cloud of tetraphosphorus decoxide. 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.When lead(II) sulfide is heated lo 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.Which of the following statements about chemical reactions is false? l type='a'> When balancing a chemical equation, all subscripts must be conserved. i>When one coefficient is doubled, the rest of the coefficients in (he balanced equation must also be doubled. i>The subscripts in a balanced equation tell us the number of atoms in a molecule. i>The phases in a chemical reaction tell us the nature of the reactants and products.73AP 74AP 75AP Using different shapes to distinguish between different elements, draw a balanced equation for the following reaction at the microscopic level. m:math>NH3(g)+O2(g)NO(g)+H2O(g)Which of the following statements about chemical equations is (are) /true? l type='a'> When balancing a chemical equation, you can never change the coefficient in front of any chemical formula. i>The coefficients in a balanced chemical equation refer to the number of grains of reactants and products. i>In a chemical equation, the reactants are on the right, and the products are on the left. i>When balancing a chemical equation, you can never change the subscripts of any chemical formula. i>In chemical reactions, matter is neither created nor destroyed, so a chemical equation must have the same number of atoms on both sides of the equation.78CP Balance the following chemical equations. msp;MnO2(s)+CO(g)Mn2O3(aq)+CO2(g)Al(s)+H2SO4(aq)Al2( SO 4)3(aq)+H2(g)C4H10(g)+O2(g)CO2(g)+H2O(l)NH4I(aq)+Cl2(g)NH4CI(aq)+I2(g)KOH(aq)+H2SO4(aq)K2SO4(aq)+H2O(l)at if no ionic solids were soluble in water? Could reactions occur in aqueous solutions?7.1SC trong>Exercise 7.2 For each of the following reactions, write the molecular equation, the complete ionic equation, and the net ionic equation. ol type='a'> Aqueous sodium sulfide is mixed with aqueous copper(II) nitrate to produce solid copper(II) sulfide and aqueous sodium nitrate. i>Aqueous ammonium chloride and aqueous lead(ll) nitrate react to form solid lead(ll) chloride and aqueous ammonium nitrate.7.3SC lton believed that atoms were indivisible. Thomson and Rutherford helped to show that this was not true. What if atoms were indivisible? How would this affect the types of reactions you have learned about in this chapter?ercise 7.4 Classify each of the following reactions in as many ways as possible. msp;4NH3(g)+5O2(g)4NO(g)+6H2O(g) msp;S8(s)+8O2(g)8SO2(g) msp;2Al(s)+3Cl2(g)2AlCl3(s) msp;2AlN(s)2Al(s)+N2(g) msp;BaCl2(aq)+Na2SO4(aq)BaSO4(s)+2NaCl(aq) msp;2Cs(s)+Br2(l)2CsBr(s) msp;KOH(aq)+HCI(aq)H2O(l)+KCI(aq) msp;2C2H2(g)+5O2(g)4CO2(g)+2H2O(l)onsider the mixing of aqueous solutions of lead(II) nitrate and sodium iodide to form a solid. . Name the possible products, and determine the formulas of these possible products. . What is the precipitate? How do you know? . Must the subscript for an ion in a reactant stay the same as the subscript of that ion in a product? Explain your answer.ssume a highly magnified view of a solution of HCI that allows you to “see” the HCl. Draw this magnified view. If you dropped in a piece of magnesium, the magnesium would disappear, and hydrogen gas would he released. Represent this change using symbols for the elements, and write the balanced equation.hy is the formation of a solid evidence of a chemical reaction? Use a molecular-level drawing in your explanation.4ALQ ixing an aqueous solution of potassium nitrate with an aqueous solution of sodium chloride does not result in a chemical reaction. Why?6ALQ se the Arrhenius definition of acids and bases to write the net ionic equation for the reaction of an acid with a base.8ALQ hy is the formation of a gas evidence of a chemical reaction? Use a molecular-level drawing in your explanation.Label each of the following statements as true or false. Explain your answers, and provide an example for each that supports your answer. l type='a'> All nonelectrolytes are insoluble. i>All insoluble substances are nonelectrolytes. i>All strong electrolytes arc soluble. i>All soluble substances are strong electrolytes.Look at Fig. 7.2 in the text. It is possible for a weak electrolyte solution to cause the bulb to glow brighter than a strong electrolyte. Explain how this is possible.What is the purpose of spectator ions? If they are not present as part of the reaction, why are they present at all?Which of the following must be an oxidation—reduction reaction? Explain your answer, and include an example oxidation—reduction reaction for all that apply. l type='a'> A metal reacts with a nonmetal. i>A precipitation reaction. i>An acid—base reaction.If an element is a reactant or product in a chemical reaction, the reaction must be an oxidation—reduction reaction. Why is this true?15ALQ On the basis of the general solubility rules given in Table 7.1, predict the identity of the precipitate that forms when aqueous solutions of the following Substances are mixed. If no precipitate is likely, indicate which rules apply. mg src=Images/HTML_99425-7-16ALQ_image001.jpg alt="" align="top"/>Write the balanced formula and net ionic equation for the reaction that occurs when the contents of the two beakers are added together. What colors represent the spectator ions in each reaction? mg src=Images/HTML_99425-7-17ALQ_image001.jpg alt="" align="top"/> mg src=Images/HTML_99425-7-17ALQ_image002.jpg alt="" align="top"/>hy is water an important solvent? Although you have not yet studied water in detail, can you think of some properties of water that make it so important?hat 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?3QAP 4QAP escribe briefly what happens when an ionic substance is dissolved in water.hen the ionic solute K3PO4is 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?7QAP ow do chemists know that the ions behave independently of one another when an ionic solid is dissolved in water?uppose you are trying to help your friend understand the general solubility rules for ionic substances in water. Explain in general terms to your friend what the solubility rules mean, and give an example of how the rules could be applied in determining the identity of the precipitate in a reaction between solutions of two ionic compounds.Using the general solubility rules given in Table 7.1, which of the following ions will form a precipitate with SO42? msp;Ba2+ msp;Na+ msp;NH4+ least two of the above ions will form a precipitate with SO42. l of the above ions will form a precipitate with SO42.On the basis of the general solubility rules given in Table 7.1, predict which of the following substances are not likely to be soluble in water. Indicate which specific rule(s) led to your conclusion. :math>PbSe. BaCO3 :math>Mg(OH)2f. AlPO4 :math>Na2SO4g. PbCl2 :math>(NH4)2Sh. CaSO4 On the basis of the general solubility rules given in Table 7.1, predict which of the following substances are likely to be appreciably soluble in water. Indicate which specific rule(s) led to your conclusion. :math>Ba(NO3)2e. KCl :math>K2SO4f. Hg2Cl2 :math>PbSO4g. (NH4)2CO3 :math>Cu(OH)2h. Cr2S3 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 substance’s particular situation. l type='a'> potassium sulfide cohalt(III) nitrate ammonium phosphate cesium sulfate strontium chloride 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 particular situation. l type='a'> iron(III) hydroxide silver chloride calcium carbonate barium sulfate cobalt(III) phosphate On the basis of the general solubility rules given in Table 7.1, predict the identity of the precipitate that forms when aqueous solutions of the following substances are mixed. If no precipitate is likely, indicate which rules apply. pper(II) chloride, CuCl2, and ammonium sulfide, (NH4)2S rium nitrate, Ba(NO3)2, and potassium phosphate. K3PO4 lver acetate, AgC2H3O2, and calcium chloride, CaCl2 tassium carbonate, K2CO3, and cobalt(II) chloride, CoCl2 lfuric acid, H2SO4, and calcium nitrate, Ca(NO3)2 rcurous acetate, Hg2(C2H3O2)2 , and hydrochloric acid, HCl 16QAP On the basis of the general solubility rules given in Table 7.1, write a balanced molecular equation for the precipitation reactions that take place when the following aqueous solutions are mixed. Underline the formula of the precipitate (solid) that forms. If no precipitation reaction is likely for the reactants given, explain why. monium chloride, NH4Cl, and sulfuric acid, H2SO4 tassium carbonate, K2CO3, and tin(IV) chloride, SnCl4 monium chloride, NH4Cl , and lead(lI) nitrate, Pb(NO3)2 pper(II) sulfate, CuSO4, and potassium hydroxide, KOH dium phosphate, Na3PO4, and chromium(III) chloride, CrCl3 monium sulfide, (NH4)2S, and iron(III) chloride, FeCl3 On the basis of the general solubility rules given in Table 7.1, write a balanced molecular equation for the precipitation reactions that take place when the following aqueous solutions are mixed. Underline the formula of the precipitate (solid) that forms. If no precipitation reaction is likely for the solutes given, so indicate. dium carbonate, Na2CO3, and copper(II) sulfate, CuSO4 drochloric acid, HCl, and silver acetate, AgC2H3O2 rium chloride, BaCl2, and calcium nitrate, Ca(NO3)2 monium sulfide, (NH4)2S, and iron(III) chloride, FeCl3 lfuric acid, H2SO4, and Iead(II) nitrate, Pb(NO3)2 tassium phosphate, K3PO4, and calcium chloride, CaCl2 Balance each of the following equations that describe precipitation reactions. l type='a'> i> i>Balance each of the following equations that describe precipitation reactions. l type='a'> i> i>For each of the following precipitation reactions, complete and balance the equation, indicating clearly which product is the precipitate, If no reaction would he expected, so indicate. l type='a'> i> i>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 net ionic equation? What species are shown in such an equation, and which species are not shown?24QAP Based on the general solubility rules given in Table 7.1, propose five combinations of aqueous ionic reagents that likely would form a precipitate when they are mixed. Write the balanced full molecular equation and the balanced net ionic equation for each of your choices.Write the balanced molecular, complete ionic, and net ionic equations for the reaction between nickel(II) chloride and sodium sulfide.Many chromate 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 and with chromate ion.The procedures and principles of qualitative analysis are coy cred 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 presence of the particular ions in the mixture. One of the first steps in such an analysis is to treat the mixture with hydrochloric acid, which precipitates and removes silver ion, lead(II) ion, and mercury(I) ion from the aqueous mixture as the insoluble chloride salts. Write balanced net ionic equations for the precipitation reactions of these three cations with chloride ion.Many plants are poisonous because their stems and leaves contain oxalic acid, or sodium oxalate, when ingested, these substances cause swelling of the respiratory tract and suffocation. A standard analysis for determining the amount of oxalate ion, in a sample is to precipitate this species as calcium oxalate, which is insoluble in water. Write the net ionic equation for the reaction between sodium oxalate and calcium chloride, in aqueous solution.30QAP What is meant by a strong acid? Are the strong acids also strong electrolytes? Explain.What is meant by a strong base? Are the strong bases also strong electrolytes? Explain.The same net ionic process takes place when any strong acid reacts with any strong base. Write the equation for that process.34QAP If 1000 NaOH units were dissolved in a sample of water, the NaOFI would produce ions and ________ ions.What is a salt? Give two balanced chemical equations showing how a salt is formed when an acid reacts with a base.Write balanced equations showing how three of the common strong acids ionize to produce hydrogen ion.38QAP What salt would form when each of the following strong acid/ strong base reactions takes place? l type='a'> i> i> i>40QAP 41QAP Give an example of a simple chemical reaction that involves the transfer of electrons from a metallic element to a nonmetallic element.What do we mean when we say that the transfer of electrons can be the “driving force” for a reaction? Give an example of a reaction where this happens.44QAP If atoms of the metal calcium were to react with molecules of the nonmetal fluorine, 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 molecule? What charges would the resulting calcium and fluoride ions have?If oxygen molecules, 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 would the resulting magnesium and oxide ions have?47QAP 48QAP 49QAP 50QAP 51QAP The reaction between ammonium perchlorate and aluminum is discussed in the “Chemistry in Focus” segment OxidationReduction Reactions Launch the Space Shuttle. The reaction is labeled as an oxidationreduction reaction. Explain why this is an oxidationreduction reaction and defend your answer.Identify each of the following unbalanced reaction equations as belonging to one or more of the following categories: precipitation, acid—base, or oxidation—reduction. l type='a'> i> i> i> i> i> i> i> i>54QAP 55QAP 56QAP What is a synthesis or combination reaction? Give an example. Can such reactions also be classified in other ways? Give an example of a synthesis reaction that is also a combustion reaction. Give an example of a synthesis reaction that is also an oxidation—reduction reaction, but that does not involve combustion.What is a decomposition reaction? Give an example. Can such reactions also be classified in other ways?Complete and balance each of the following combustion reactions. l type='a'> i> i>60QAP 61QAP 62QAP Balance each of the following equations that describe synthesis react ions. msp;CaO(s)+H2O(l)Ca(OH)2(s) msp;Fe(s)+O2(g)Fe2O3(s) msp;P2O5(s)+H2O(l)H3PO4(aq)64QAP Balance each of the following equations that describe decomposition reactions. msp;CaSO4(s)CaO(s)+SO3(g) msp;Li2CO3(s)Li2O(s)+CO2(g) msp;LiHCO3(s)Li2CO3(s)+H2O(g)+CO2(g) msp;C6H6(l)C(s)+H2(g) msp;PBr(l)P2(s)+Br2(l)66QAP Distinguish between the molecular equation, the complete ionic equation, and the net ionic equation for a reaction in solution. Which type of equation most clearly shows the species that actually react with one another?68AP Without first writing a full molecular or ionic equation, write the net ionic equations for any precipitation reactions that occur when aqueous solutions of the following compounds are mixed. If no reaction occurs, so indicate. l type='a'> iron(III) nitrate and sodium carbonate mercurous nitrate and sodium chloride sodium nitrate and ruthenium nitrate copper(II) sulfate and sodium sulfide lithium chloride and Iead(II) nitrate calcium nitrate and lithium carbonate gold(III) chloride and sodium hydroxide Complete and balance each of the following molecular equations for strong acid/strong base reactions. Underline the formula of the salt produced in each reaction. msp;NNO3(aq)+KOH(aq) msp;H2SO4(aq)+Ba(OH)2(aq) msp;HClO4(aq)+NaOH(aq) msp;HCl(aq)+Ca(OH)2(aq)71AP 72AP 73AP 74AP For each of the following unbalanced molecular equations, write the corresponding balanced net ionic equation for the reaction. msp;HCl(aq)+AgNO3(aq)AgCl(s)+HNO3(aq) msp;CaCl2(aq)+Na3PO4(aq)Ca3(PO4)2(s)+NaCl(aq) msp;Pb(NO3)2(aq)+BaCl2(aq)PbCl2(s)+Ba(NO3)2(aq) msp;FeCl3(aq)+NaOH(aq)Fe(OH)3(s)+NaCl(aq)Write the balanced molecular, complete ionic, and net ionic equations for the reaction of ammonium sulfide with iron(III) chloride.What strong acid and what strong base would react in aqueous solution to produce the following salts? potassium perchlorate, KClO4 sium nitrate, CsNO3 tassium chloride, KCl dium sulfate, Na2SO4 78AP For the reaction 16Fe(s)+3S8(s)8Fe2S3(s), show how electrons are gained and lost by the atoms.80AP Identify each of the following unbalanced reaction equations as belonging to one or more of the following categories: precipitation, acidbase, or oxidationreduction. msp;Fe(s)+H2SO4(aq)Fe3(SO4)2(aq)+H2(g) msp;HClO4(aq)+RbOH(aq)RbCIO4(aq)+H2O(l) msp;Ca(s)+O2(g)CaO(s) msp;H2SO4(aq)+NaOH(aq)Na2SO4(aq)+H2O(l) msp;Pb(NO3)2(aq)+Na2CO3(aq)PbCO3(s)+NaNO3(aq) msp;K2SO4(aq)+CaCl2(aq)KCl(aq)+CaSO4(s) msp;HNO3(aq)+KOH(aq)KNO3(aq)+H2O(l) msp;Ni(C2H3O2)2(aq)+Na2S(aq)NiS(s)+NaC2H3O2(aq) msp;Ni(s)+Cl2(g)NiCl2(s)Which of the following statements is/are true regarding solutions? l type='a'> If a solute is dissolved in water, then the resulting solution is considered aqueous. i>If two solutions are mixed and no chemical reaction occurs, then a net ionic equation cannot be written. i>If two clear solutions are mixed and then cloudiness results, this indicates that a precipitate formed.83AP 84AP 85AP 86AP 87AP For each of the following metals, how many electrons will the metal atoms lose when the metal reacts with a nonmetal? ol type='a'> sodium barium potassium aluminum magnesium For each of the following nonmetals, how many electrons will each atom of the nonmetal gain in reacting with a metal? ol type='a'> oxygen chlorine fluorine sulfur nitrogen True or false? When solutions of barium hydroxide and sulfuric acid are mixed, the net ionic equation is: Ba2+(aq)+SO42(aq)BaSO4(s)because only the species involved in making the precipitate are included. Whether true or false, include a balanced molecular equation and complete ionic equation for the reaction between barium hydroxide and sulfuric acid to support your answer.Classify the reactions represented by the following unbalanced equations by as many methods as possible. Balance the equations. msp;I4O9(s)I2O6(s)+I2(s)+O2(g) msp;Mg(s)+AgNO3(aq)Mg(NO3)2(aq)+Ag(s) msp;SiCl4(l)+Mg(s)MgCl2(s)+Si(s) msp;CuCl2(aq)+AgNO3(aq)Cu(NO3)2(aq)+AgCl(s) msp;Al(s)+Br2(l)AlBr3(s)When a sodium chromate solution and aluminum bromide solution are mixed, a precipitate forms. Complete and balance the equation for this reaction, including the phases of each reactant and product.93AP Consider a solution with the following ions present: :math>NO3,Pb2+,K+,Ag+,Cl,SO42,PO43+ l are allowed to react, and there are plenty available of each. List all of the solids that will form using the correct formulas in your explanation.95AP 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. msp;FormulaofPrecipitateNa2SO4(aq)+Pb(NO3)2(aq)_(s)AgNO3(aq)+KCl(aq)_(s)NCl(aq)+NaNO3(aq)_(s)97CP hat kind of visual evidence indicates that a chemical reaction has occurred? Give an example of each type of evidence you have mentioned. Do all reactions produce visual evidence that they have taken place?2CR 3CR 4CR hat is meant by the driving force for a reaction? Give some examples of driving forces that make reactants tend to form products. Write a balanced chemical equation illustrating each type of driving force you have named.xplain to your friend what chemists mean by a precipitation reaction. What is the driving force in a precipitation reaction? Using the information provided about solubility in these chapters, write balanced molecular and net ionic equations for five examples of precipitation reactions.efine the term strong electrolyte. What types of substances tend to be strong electrolytes? What does a solution of a strong electrolyte contain? Give a way to determine if a substance is a strong electrolyte.ummarize the simple solubility rules for ionic compounds. How do we use these rules in determining the identity of the solid formed in a precipitation reaction? Give examples including balanced complete and net ionic equations.n general terms, what are the spectator ions in a precipitation reaction? Why are the spectator ions not included in writing the net ionic equation for a precipitation reaction? Does this mean that the spectator ions do not have to be present in the solution?Describe some physical and chemical properties of acids and bases. What is meant by a strong acid or base? Are strong acids and bases also strong electrolytes? Give several examples of strong acids and strong bases.11CR What do we call reactions in which electrons are transferred between atoms or ions? What do we call a loss of electrons by an atom or ion? What is it called when an atom or ion gains electrons? Can we have a process in which electrons are lost by one species without there also being a process in which the electrons are gained by another species? Why? Give three examples of equations in which there is a transfer of electrons between a metallic element and a nonmetallic element. In your examples, identify which species loses electrons and which species gains electrons.What is a combustion reaction? Are combustion reactions a unique type of reaction, or are they a special case of a more general type of reaction? Write an equation that illustrates a combustion reaction.14CR List and define all the ways of classifying chemical reactions that have been discussed in the text. Give a balanced chemical equation as an example of each type of reaction, and show clearly how your example fits the definition you have given.The element carbon undergoes many inorganic reactions, as well as being the basis for the field of organic chemistry. Write balanced chemical equations for the reactions of carbon described below. l type='a'> Carbon burns in an excess of oxygen (for example. in the air) to produce carbon dioxide. If the supply of oxygen is limited, carbon will still burn but will produce carbon monoxide rather than carbon dioxide. molten lithium metal is treated with carbon, lithium car bide, Li2C2 , is produced. i>Iron(II) oxide reacts with carbon above temperatures of about 700 °C to produce carbon monoxide gas and molten elemental iron. i>Carbon reacts with fluorine gas at high temperatures to make carbon tetrafluoride.17CR The reagent shelf in a general chemistry lab contains aqueous solutions of the following substances: silver nitrate, sodium chloride, acetic acid, nitric acid, sulfuric acid, potassium chromate, barium nitrate, phosphoric acid, hydrochloric acid, lead nitrate, sodium hydroxide, and sodium carbonate. Suggest how you might prepare the following pure substances using these reagents and any normal laboratory equipment. If it is not possible to prepare a substance using these reagents. indicate why. :math>BaCrO4(s) d. PbSO4(s) :math>NaC2H3O2(s)e. Na2SO4(s) msp;AgCl(s) f. i> BaCO3(s)19CR 20CR 21CR 22CR Using the general solubility rules discussed in Chapter 7, give the formulas of live substances that would be expected to be readily soluble in water and five substances that would be expected to not be very soluble in water. For each of the substances you choose, indicate the specific solubility rule you applied to make your prediction.Write the balanced net ionic equation for the reaction that takes place when aqueous solutions of the following solutes are mixed. If no reaction is likely, explain why no reaction would be expected for that combination of solutes. l type='a'> potassium nitrate and sodium chloride calcium nitrate and sulfuric acid ammonium sulfide and lead(II) nitrate sodium carbonate and iron(III) chloride mercurous nitrate and calcium chloride silver acetate and potassium chloride i>phosphoric acid and calcium nitrate sulfuric acid and nickel(II) sulfate 25CR ercise 8.1 Calculate the mass of a sample that contains 23 nitrogen atoms.8.2SC at if you were offered $1 million to count from 1 to 61023 at a rate ofone number each second? Determine your hourly wage. Would you do it?Could you do it?at if you discovered Avogadro’s number was not 6.021023 but 3.011023 ? Would this affect the relative masses given on the periodic table? If so, how? If not, why not?ercise 8.3 Chromium (Cr) is a metal that is added to steel to improve its resistance to corrosion (for example, to make stainless steel). Calculate both the number of moles in a sample of chromium containing 5.001020 atoms and the mass of the sample.ercise 8.4 Polyvinyl chloride (called PVC), which is widely used for floor coverings (“vinyl’) and for plastic pipes in plumbing systems, is made from a molecule with the formula C2H3Cl . Calculate the molar mass of this substance.ercise 8.5 Calculate the molar mass for sodium sulfate, Na2SO4 . A sample of sodium sulfate with a mass of 300.0 g represents what number of moles of sodium sulfate?ercise 8.6 The substance Teflon, the slippery coating on many frying pans, is made from the C2F4 molecule. Calculate the number of C2F4 units present in 135 g of Teflon.ercise 8.7 Penicillin, an important antibiotic (antibacterial agent), was discovered accidentally by the Scottish bacteriologist Alexander Fleming in 1928, although he was never able to isolate it as a pure compound. This and similar antibiotics have saved millions of lives that would otherwise have been lost to infections. Penicillin, like many of the molecules produced by living systems, is a large molecule containing many atoms. One type of penicillin, penicillin F, has the formula C14H20N2SO4 . Compute the mass percent of each element in this compound.ercise 8.8 In a lab experiment it was observed that 0.6884 g of lead combines with 0.2356 g of chlorine to form a binary compound. Calculate the empirical formula of this compound.trong>Exercise 8.9 Sevin, the commercial name for an insecticide used to protect crops such as cotton, vegetables, and fruit, is made from carbamic acid. A chemist analyzing a sample of carbamic acid finds 0.8007 g of carbon, 0.9333 g of nitrogen, 0.2016 g of hydrogen, and 2.133 g of oxygen. Determine the empirical formula for carbamic acid.e part of the problem-solving strategy for empirical formula determination is to base the calculation on 100 g of compound. What if you chose a mass other than 100 g? Would this work? What if you chose to base the calculation on 100 moles of compound? Would this work?ercise 8.10 The most common form of nylon (Nylon-6) is 63.68% carbon, 12.38% nitrogen, 9.80% hydrogen, and 14.14% oxygen. Calculate the empirical formula for Nylon-6.Exercise 8.11 A compound used as an additive for gasoline to help prevent engine knock shows the following percent composition: 7 1.65% Cl 24.27% C 4.07% H The molar mass is known to be 98.96 g. Determine the empirical formula and the molecular formula for this compound.n chemistry, what is meant by the term mole? What is the importance of the mole concept?hat is the difference between the empirical and molecular for mulas of a compound? Can they ever be the same? Explain.substance A2B is 60% A by mass. Calculate the present B (by mass) for AB2 .ive the formula for calcium phosphate and then answer the following questions: l type='a'> Calculate the percent composition of each of the elements in this compound. i>If you knew that there was 50.0 g of phosphorus in your sample, how many grams of calcium phosphate would you have? How many moles of calcium phosphate would this be? How many formula units of calcium phosphate?ow would you find the number of “chalk molecules” it takes to write your name on the hoard? Explain what you would need to do, and provide a sample calculation.0.821 -mol sample of a substance composed of diatom of molecules has a mass of 131.3 g. Identify this molecule.ow many molecules of water are there in a 10.0-g sample of water? How many hydrogen atoms are there in this sample?hat is the mass (in grams) of one molecule of ammonia?onsider separate 100.0-g samples of each of the following: NH3 , N2O , N2H4 , HCN , HNO3 . Arrange these samples from largest mass of nitrogen to smallest mass of nitrogen and prove/ explain your order.A molecule has a mass of 4.651023 g. Provide two possible chemical formulas for such a molecule.Differentiate between the terms atomic mass and molar mass.Consider Figure 4.19 in the text. Why is it that the formulas for ionic compounds are always empirical formulas?Why do we need to count atoms by weighing them?The following claim is made in your text: 1 mole of marbles is enough to cover the entire earth to a depth of 50 miles. Provide mathematical support for this claim. Is it reasonably accurate?

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