Solved: Zinc and magnesium metal each react with hydrochloric acid according to the

What mass of barium sulfate can be produced when 100.0 mL of a 0.100-M solution of barium chloride is mixed with 100.0 mL of a 0.100-M solution of iron(III) sulfate?

What mass of solid AgBr is produced when 100.0 mL of 0.150 M AgNO3 is added to 20.0 mL of 1.00 M NaBr?

What mass of silver chloride can be prepared by the reaction of 100.0 mL of 0.20 M silver nitrate with 100.0 mL of 0.15 M calcium chloride? Calculate the concentrations of each ion remaining in solution after precipitation is comple

A 100.0-mL aliquot of 0.200 M aqueous potassium hydroxide is mixed with 100.0 mL of 0.200 M aqueous magnesium nitrate. a. Write a balanced chemical equation for any reaction that occurs. b. What precipitate forms? c. What mass of precipitate is produced? d. Calculate the concentration of each ion remaining in solution after precipitat

The drawings below represent aqueous solutions. Solution A is 2.00 L of a 2.00-M aqueous solution of copper(II) nitrate. Solution B is 2.00 L of a 3.00-M aqueous solution of potassium hydroxide. Cu2+ NO3 K+ OH A B

Draw a picture of the solution made by mixing solutions A and B together after the precipitation reaction takes place. Make sure this picture shows the correct relative volume compared to solutions A and B, and the correct relative number of ions, along with the correct relative amount of solid formed b. Determine the concentrations (in M) of all ions left in solution (from part a) and the mass of solid formed

A 1.42-g sample of a pure compound, with formula M2SO4, was dissolved in water and treated with an excess of aqueous calcium chloride, resulting in the precipitation of all the sulfate ions as calcium sulfate. The precipitate was collected, dried, and found to weigh 1.36 g. Determine the atomic mass of M, and identify M

You are given a 1.50-g mixture of sodium nitrate and sodium chloride. You dissolve this mixture into 100 mL of water and then add an excess of 0.500 M silver nitrate solution. You produce a white solid, which you then collect, dry, and measure. The white solid has a mass of 0.641 g. a. If you had an extremely magnified view of the solution (to the atomic-molecular level), list the species you would see (include charges, if any). b. Write the balanced net ionic equation for the reaction that produces the solid. Include phases and charges. c. Calculate the percent sodium chloride in the original unknown mixture

Write the balanced formula, complete ionic, and net ionic equations for each of the following acidbase reactions. a. HClO4 1aq2 1 Mg1OH2 2 1s2 S b. HCN1aq2 1 NaOH1aq2 S c. HCl1aq2 1 NaOH1aq2 S

Write the balanced formula, complete ionic, and net ionic equations for each of the following acidbase reactions. a. HNO3 1aq2 1 Al1OH2 3 1s2 S b. HC2H3O2 1aq2 1 KOH1aq2 S c. Ca1OH2 2 1aq2 1 HCl1aq2 S

Write the balanced formula equation for the acidbase reactions that occur when the following are mixed. a. potassium hydroxide (aqueous) and nitric acid b. barium hydroxide (aqueous) and hydrochloric acid c. perchloric acid [HClO4(aq)] and solid iron(III) hydroxide d. solid silver hydroxide and hydrobromic acid e. aqueous strontium hydroxide and hydroiodic acid

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

What volume of each of the following acids will react completely with 50.00 mL of 0.200 M NaOH? a. 0.100 M HCl b. 0.150 M HNO3 c. 0.200 M HC2H3O2 (1 acidic hydrogen)

What volume of each of the following bases will react completely with 25.00 mL of 0.200 M HCl? a. 0.100 M NaOH c. 0.250 M KOH b. 0.0500 M Sr(OH)2

Hydrochloric acid (75.0 mL of 0.250 M) is added to 225.0 mL of 0.0550 M Ba(OH)2 solution. What is the concentration of the excess H1 or OH2 ions left in this solution?

A student mixes four reagents together, thinking that the solutions will neutralize each other. The solutions mixed together are 50.0 mL of 0.100 M hydrochloric acid, 100.0 mL of 0.200 M of nitric acid, 500.0 mL of 0.0100 M calcium hydroxide, and 200.0 mL of 0.100 M rubidium hydroxide. Did the acids and bases exactly neutralize each other? If not, calculate the concentration of excess H1 or OH2 ions left in solution.

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

A 10.00-mL sample of vinegar, an aqueous solution of acetic acid (HC2H3O2), is titrated with 0.5062 M NaOH, and 16.58 mL is required to reach the equivalence point. a. What is the molarity of the acetic acid? b. If the density of the vinegar is 1.006 g/cm3 , what is the mass percent of acetic acid in the vinegar?

What volume of 0.0200 M calcium hydroxide is required to neutralize 35.00 mL of 0.0500 M nitric acid?

A 30.0-mL sample of an unknown strong base is neutralized after the addition of 12.0 mL of a 0.150 M HNO3 solution. If the unknown base concentration is 0.0300 M, give some possible identities for the unknown base.

A student titrates an unknown amount of potassium hydrogen phthalate (KHC8H4O4, often abbreviated KHP) with 20.46 mL of a 0.1000-M NaOH solution. KHP (molar mass 5 204.22 g/ mol) has one acidic hydrogen. What mass of KHP was titrated (reacted completely) by the sodium hydroxide solution?

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

Assign oxidation states for all atoms in each of the following compounds. a. KMnO4 f. Fe3O4 b. NiO2 g. XeOF4 c. Na4Fe(OH)6 h. SF4 d. (NH4)2HPO4 i. CO e. P4O6 j. C6H12O

Assign oxidation states for all atoms in each of the following compounds. a. UO2 21 f. Mg2P2O7 b. As2O3 g. Na2S2O3 c. NaBiO3 h. Hg2Cl2 d. As4 i. Ca(NO3)2 e. HAsO2

Assign the oxidation state for nitrogen in each of the following. a. Li3N f. NO2 b. NH3 g. NO2 2 c. N2H4 h. NO3 2 d. NO i. N2 e. N2O

Assign oxidation numbers to all the atoms in each of the following. a. SrCr2O7 g. PbSO3 b. CuCl2 h. PbO2 c. O2 i. Na2C2O4 d. H2O2 j. CO2 e. MgCO3 k. (NH4)2Ce(SO4)3 f. Ag l. Cr2O3

Specify which of the following are oxidationreduction reactions, and identify the oxidizing agent, the reducing agent, the substance being oxidized, and the substance being reduced. a. Cu1s2 1 2Ag1 1aq2 S 2Ag1s2 1 Cu21 1aq2 b. HCl1g2 1 NH3 1g2 S NH4Cl1s2 c. SiCl4 1l2 1 2H2O1l2 S 4HCl1aq2 1 SiO2 1s2 d. SiCl4 1l2 1 2Mg1s2 S 2MgCl2 1s2 1 Si1s2 e. Al1OH2 4 2 1aq2 S AlO2 2 1aq2 1 2H2O1l2

Specify which of the following equations represent oxidation reduction reactions, and indicate the oxidizing agent, the reducing agent, the species being oxidized, and the species being reduced. a. CH4 1g2 1 H2O1g2 S CO1g2 1 3H2 1g2 b. 2AgNO3 1aq2 1 Cu1s2 S Cu1NO32 2 1aq2 1 2Ag1s2 c. Zn1s2 1 2HCl1aq2 S ZnCl2 1aq2 1 H2 1g2 d. 2H1 1aq2 1 2CrO4 22 1aq2 S Cr2O7 22 1aq2 1 H2O1l2

Consider the reaction between sodium metal and fluorine (F2) gas to form sodium fluoride. Using oxidation states, how many electrons would each sodium atom lose, and how many electrons would each fluorine atom gain? How many sodium atoms are needed to react with one fluorine molecule? Write a balanced equation for this reaction.

Consider the reaction between oxygen (O2) gas and magnesium metal to form magnesium oxide. Using oxidation states, how many electrons would each oxygen atom gain, and how many electrons would each magnesium atom lose? How many magnesium atoms are needed to react with one oxygen molecule? Write a balanced equation for this reaction.

Balance each of the following oxidationreduction reactions by using the oxidation states method. a. C2H6 1g2 1 O2 1g2 S CO2 1g2 1 H2O1g2 b. Mg1s2 1 HCl1aq2 S Mg21 1aq2 1 Cl2 1aq2 1 H2 1g2 c. Co31 1aq2 1 Ni1s2 S Co21 1aq2 1 Ni21 1aq2 d. Zn1s2 1 H2SO4 1aq2 S ZnSO4 1aq2 1 H2 1g2

Balance each of the following oxidationreduction reactions by using the oxidation states method. a. Cl2 1g2 1 Al1s2 S Al31 1aq2 1 Cl2 1aq2 b. O2 1g2 1 H2O1l2 1 Pb1s2 S Pb1OH2 2 1s2 c. H1 1aq2 1 MnO4 2 1aq2 1 Fe21 1aq2 S Mn21 1aq2 1 Fe31 1aq2 1 H2O1l2

You wish to prepare 1 L of a 0.02-M potassium iodate solution. You require that the final concentration be within 1% of 0.02 M and that the concentration must be known accurately to the fourth decimal place. How would you prepare this solution? Specify the glassware you would use, the accuracy needed for the balance, and the ranges of acceptable masses of KIO3 that can be used.

The figures below are molecular-level representations of four aqueous solutions of the same solute. Arrange the solutions from most to least concentrated. Solution A (1.0 L) Solution B (4.0 L) Solution C (2.0 L) Solution D (2.0 L)

An average human being has about 5.0 L of blood in his or her body. If an average person were to eat 32.0 g of sugar (sucrose, C12H22O11, 342.30 g/mol), and all that sugar were dissolved into the bloodstream, how would the molarity of the blood sugar change?

A 230.-mL sample of a 0.275-M CaCl2 solution is left on a hot plate overnight; the following morning, the solution is 1.10 M. What volume of water evaporated from the 0.275 M CaCl2 solution?

Using the general solubility rules given in Table 4.1, name three reagents that would form precipitates with each of the following ions in aqueous solution. Write the net ionic equation for each of your suggestions. a. chloride ion d. sulfate ion b. calcium ion e. mercury(I) ion, Hg2 21 c. iron(III) ion f. silver ion

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

A 1.00-g sample of an alkaline earth metal chloride is treated with excess silver nitrate. All of the chloride is recovered as 1.38 g of silver chloride. Identify the metal.

A mixture contains only NaCl and Al2(SO4)3. A 1.45-g sample of the mixture is dissolved in water and an excess of NaOH is added, producing a precipitate of Al(OH)3. The precipitate is filtered, dried, and weighed. The mass of the precipitate is 0.107 g. What is the mass percent of Al2(SO4)3 in the sample?

The thallium (present as Tl2SO4) in a 9.486-g pesticide sample was precipitated as thallium(I) iodide. Calculate the mass percent of Tl2SO4 in the sample if 0.1824 g of TlI was recovered.

A mixture contains only NaCl and Fe(NO3)3. A 0.456-g sample of the mixture is dissolved in water, and an excess of NaOH is added, producing a precipitate of Fe(OH)3. The precipitate is filtered, dried, and weighed. Its mass is 0.107 g. Calculate the following. a. the mass of iron in the sample b. the mass of Fe(NO3)3 in the sample c. the mass percent of Fe(NO3)3 in the sample

A student added 50.0 mL of an NaOH solution to 100.0 mL of 0.400 M HCl. The solution was then treated with an excess of aqueous chromium(III) nitrate, resulting in formation of 2.06 g of precipitate. Determine the concentration of the NaOH solution.

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

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

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

A 2.20-g sample of an unknown acid (empirical formula 5 C3H4O3) is dissolved in 1.0 L of water. A titration required 25.0 mL of 0.500 M NaOH to react completely with all the acid present. Assuming the unknown acid has one acidic proton per molecule, what is the molecular formula of the unknown acid?

Carminic acid, a naturally occurring red pigment extracted from the cochineal insect, contains only carbon, hydrogen, and oxygen. It was commonly used as a dye in the first half of the nineteenth century. It is 53.66% C and 4.09% H by mass. A titration required 18.02 mL of 0.0406 M NaOH to neutralize 0.3602 g carminic acid. Assuming that there is only one acidic hydrogen per molecule, what is the molecular formula of carminic acid?

Chlorisondamine chloride (C14H20Cl6N2) is a drug used in the treatment of hypertension. A 1.28-g sample of a medication containing the drug was treated to destroy the organic material and to release all the chlorine as chloride ion. When the filtered solution containing chloride ion was treated with an excess of silver nitrate, 0.104 g silver chloride was recovered. Calculate the mass percent of chlorisondamine chloride in the medication, assuming the drug is the only source of chloride.

Saccharin (C7H5NO3S) is sometimes dispensed in tablet form. Ten tablets with a total mass of 0.5894 g were dissolved in water. The saccharin was oxidized to convert all the sulfur to sulfate ion, which was precipitated by adding an excess of barium chloride solution. The mass of BaSO4 obtained was 0.5032 g. What is the average mass of saccharin per tablet? What is the average mass percent of saccharin in the tablets?

Douglasite is a mineral with the formula 2KCl # FeCl2 # 2H2O. Calculate the mass percent of douglasite in a 455.0-mg sample if it took 37.20 mL of a 0.1000-M AgNO3 solution to precipitate all the Cl2 as AgCl. Assume the douglasite is the only source of chloride ion.

Many oxidationreduction reactions can be balanced by inspection. Try to balance the following reactions by inspection. In each reaction, identify the substance reduced and the substance oxidized. a. Al1s2 1 HCl1aq2 S AlCl3 1aq2 1 H2 1g2 b. CH4 1g2 1 S1s2 S CS2 1l2 1 H2S1g2 c. C3H8 1g2 1 O2 1g2 S CO2 1g2 1 H2O1l2 d. Cu1s2 1 Ag1 1aq2 S Ag1s2 1 Cu21 1aq2

The blood alcohol (C2H5OH) level can be determined by titrating a sample of blood plasma with an acidic potassium dichromate solution, resulting in the production of Cr31(aq) and carbon dioxide. The reaction can be monitored because the dichromate ion (Cr2O7 22) is orange in solution, and the Cr31 ion is green. The balanced equation is 16H1 1aq2 1 2Cr2O7 22 1aq2 1 C2H5OH1aq2 h 4Cr31 1aq2 1 2CO2 1g2 1 11H2O1l2 This reaction is an oxidationreduction reaction. What species is reduced, and what species is oxidized? How many electrons are transferred in the balanced equation above?

Calculate the concentration of all ions present when 0.160 g of MgCl2 is dissolved in 100.0 mL of solution.

A solution is prepared by dissolving 0.6706 g oxalic acid (H2C2O4) in enough water to make 100.0 mL of solution. A 10.00-mL aliquot (portion) of this solution is then diluted to a final volume of 250.0 mL. What is the final molarity of the oxalic acid solution?

For the following chemical reactions, determine the precipitate produced when the two reactants listed below are mixed together. Indicate none if no precipitate will form. Formula of Precipitate Sr(NO3)2(aq) 1 K3PO4(aq) 88n _______________ (s) K2CO3(aq) 1 AgNO3(aq) 88n _______________ (s) NaCl(aq) 1 KNO3(aq) 88n _______________ (s) KCl(aq) 1 AgNO3(aq) 88n _______________ (s) FeCl3(aq) 1 Pb(NO3)2(aq) 88n _______________ (s)

What volume of 0.100 M NaOH is required to precipitate all of the nickel(II) ions from 150.0 mL of a 0.249-M solution of Ni(NO3)2

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

A 450.0-mL sample of a 0.257-M solution of silver nitrate is mixed with 400.0 mL of 0.200 M calcium chloride. What is the concentration of Cl2 in solution after the reaction is complete?

The zinc in a 1.343-g sample of a foot powder was precipitated as ZnNH4PO4. Strong heating of the precipitate yielded 0.4089 g Zn2P2O7. Calculate the mass percent of zinc in the sample of foot powder.

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

When organic compounds containing sulfur are burned, sulfur dioxide is produced. The amount of SO2 formed can be determined by the reaction with hydrogen peroxide: H2O2 1aq2 1 SO2 1g2 h H2SO4 1aq2 The resulting sulfuric acid is then titrated with a standard NaOH solution. A 1.302-g sample of coal is burned and the SO2 is collected in a solution of hydrogen peroxide. It took 28.44 mL of a 0.1000-M NaOH solution to titrate the resulting sulfuric acid. Calculate the mass percent of sulfur in the coal sample. Sulfuric acid has two acidic hydrogens

Assign the oxidation state for the element listed in each of the following compounds: Oxidation State S in MgSO4 _______________ Pb in PbSO4 _______________ O in O2 _______________ Ag in Ag _______________ Cu in CuCl2

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

The units of parts per million (ppm) and parts per billion (ppb) are commonly used by environmental chemists. In general, 1 ppm means 1 part of solute for every 106 parts of solution. Mathematically, by mass: ppm 5 mg solute g solution 5 mg solute kg solution In the case of very dilute aqueous solutions, a concentration of 1.0 ppm is equal to 1.0 mg of solute per 1.0 mL, which equals 1.0 g solution. Parts per billion is defined in a similar fashion. Calculate the molarity of each of the following aqueous solutions. a. 5.0 ppb Hg in H2O b. 1.0 ppb CHCl3 in H2O c. 10.0 ppm As in H2O d. 0.10 ppm DDT (C14H9Cl5) in H2O

In the spectroscopic analysis of many substances, a series of standard solutions of known concentration are measured to generate a calibration curve. How would you prepare standard solutions containing 10.0, 25.0, 50.0, 75.0, and 100. ppm of copper from a commercially produced 1000.0-ppm solution? Assume each solution has a final volume of 100.0 mL. (See Exercise 121 for definitions.)

In most of its ionic compounds, cobalt is either Co(II) or Co(III). One such compound, containing chloride ion and waters of hydration, was analyzed, and the following results were obtained. A 0.256-g sample of the compound was dissolved in water, and excess silver nitrate was added. The silver chloride was filtered, dried, and weighed, and it had a mass of 0.308 g. A second sample of 0.416 g of the compound was dissolved in water, and an excess of sodium hydroxide was added. The hydroxide salt was filtered and heated in a flame, forming cobalt(III) oxide. The mass of cobalt(III) oxide formed was 0.145 g. a. What is the percent composition, by mass, of the compound? b. Assuming the compound contains one cobalt ion per formula unit, what is the formula? c. Write balanced equations for the three reactions described

Polychlorinated biphenyls (PCBs) have been used extensively as dielectric materials in electrical transformers. Because PCBs have been shown to be potentially harmful, analysis for their presence in the environment has become very important. PCBs are manufactured according to the following generic reaction: C12H10 1 nCl2 S C12H102nCln 1 nHCl This reaction results in a mixture of PCB products. The mixture is analyzed by decomposing the PCBs and then precipitating the resulting Cl2 as AgCl. a. Develop a general equation that relates the average value of n to the mass of a given mixture of PCBs and the mass of AgCl produced. b. A 0.1947-g sample of a commercial PCB yielded 0.4791 g of AgCl. What is the average value of n for this sample?

Consider the reaction of 19.0 g of zinc with excess silver nitrite to produce silver metal and zinc nitrite. The reaction is stopped before all the zinc metal has reacted and 29.0 g of solid metal is present. Calculate the mass of each metal in the 29.0-g mixture.

A mixture contains only sodium chloride and potassium chloride. A 0.1586-g sample of the mixture was dissolved in water. It took 22.90 mL of 0.1000 M AgNO3 to completely precipitate all the chloride present. What is the composition (by mass percent) of the mixture?

You are given a solid that is a mixture of Na2SO4 and K2SO4. A 0.205-g sample of the mixture is dissolved in water. An excess of an aqueous solution of BaCl2 is added. The BaSO4 that is formed is filtered, dried, and weighed. Its mass is 0.298 g. What mass of SO4 22 ion is in the sample? What is the mass percent of SO4 22 ion in the sample? What are the percent compositions by mass of Na2SO4 and K2SO4 in the sample?

Zinc and magnesium metal each react with hydrochloric acid according to the following equations: Zn1s2 1 2HCl1aq2 h ZnCl2 1aq2 1 H2 1g2 Mg1s2 1 2HCl1aq2 h MgCl2 1aq2 1 H2 1g2 A 10.00-g mixture of zinc and magnesium is reacted with the stoichiometric amount of hydrochloric acid. The reaction mixture is then reacted with 156 mL of 3.00 M silver nitrate to produce the maximum possible amount of silver chloride. a. Determine the percent magnesium by mass in the original mixture. b. If 78.0 mL of HCl was added, what was the concentration of the HCl?

You made 100.0 mL of a lead(II) nitrate solution for lab but forgot to cap it. The next lab session you noticed that there was only 80.0 mL left (the rest had evaporated). In addition, you forgot the initial concentration of the solution. You decide to take 2.00 mL of the solution and add an excess of a concentrated sodium chloride solution. You obtain a solid with a mass of 3.407 g. What was the concentration of the original lead(II) nitrate solution?

Consider reacting copper(II) sulfate with iron. Two possible reactions can occur, as represented by the following equations. copper1II2 sulfate1aq2 1 iron1s2 h copper1s2 1 iron1II2 sulfate1aq2 copper1II2 sulfate1aq2 1 iron1s2 h copper1s2 1 iron1III2 sulfate1aq2 You place 87.7 mL of a 0.500-M solution of copper(II) sulfate in a beaker. You then add 2.00 g of iron filings to the copper(II) sulfate solution. After one of the above reactions occurs, you isolate 2.27 g of copper. Which equation above describes the reaction that occurred? Support your answe

Consider an experiment in which two burets, Y and Z, are simultaneously draining into a beaker that initially contained 275.0 mL of 0.300 M HCl. Buret Y contains 0.150 M NaOH and buret Z contains 0.250 M KOH. The stoichiometric point in the titration is reached 60.65 minutes after Y and Z were started simultaneously. The total volume in the beaker at the stoichiometric point is 655 mL. Calculate the flow rates of burets Y and Z. Assume the flow rates remain constant during the experiment

Complete and balance each acidbase reaction. a. H3PO4 1aq2 1 NaOH1aq2 S Contains three acidic hydrogens b. H2SO4 1aq2 1 Al1OH2 3 1s2 S Contains two acidic hydrogens c. H2Se1aq2 1 Ba1OH2 2 1aq2 S Contains two acidic hydrogens d. H2C2O4 1aq2 1 NaOH1aq2 S Contains two acidic hydrogens

What volume of 0.0521 M Ba(OH)2 is required to neutralize exactly 14.20 mL of 0.141 M H3PO4? Phosphoric acid contains three acidic hydrogens.

A 10.00-mL sample of sulfuric acid from an automobile battery requires 35.08 mL of 2.12 M sodium hydroxide solution for complete neutralization. What is the molarity of the sulfuric acid? Sulfuric acid contains two acidic hydrogens

A 0.500-L sample of H2SO4 solution was analyzed by taking a 100.0-mL aliquot and adding 50.0 mL of 0.213 M NaOH. After the reaction occurred, an excess of OH2 ions remained in the solution. The excess base required 13.21 mL of 0.103 M HCl for neutralization. Calculate the molarity of the original sample of H2SO4. Sulfuric acid has two acidic hydrogens

A 6.50-g sample of a diprotic acid requires 137.5 mL of a 0.750 M NaOH solution for complete neutralization. Determine the molar mass of the acid

Citric acid, which can be obtained from lemon juice, has the molecular formula C6H8O7. A 0.250-g sample of citric acid dissolved in 25.0 mL of water requires 37.2 mL of 0.105 M NaOH for complete neutralization. What number of acidic hydrogens per molecule does citric acid have?

A stream flows at a rate of 5.00 3 104 liters per second (L/s) upstream of a manufacturing plant. The plant discharges 3.50 3 103 L/s of water that contains 65.0 ppm HCl into the stream. (See Exercise 121 for definitions.) a. Calculate the streams total flow rate downstream from this plant. b. Calculate the concentration of HCl in ppm downstream from this plant. c. Further downstream, another manufacturing plant diverts 1.80 3 104 L/s of water from the stream for its own use. This plant must first neutralize the acid and does so by adding lime: CaO1s2 1 2H1 1aq2 h Ca21 1aq2 1 H2O1l2 What mass of CaO is consumed in an 8.00-h work day by this plant? d. The original stream water contained 10.2 ppm Ca21. Although no calcium was in the waste water from the first plant, the waste water of the second plant contains Ca21 from the neutralization process. If 90.0% of the water used by the second plant is returned to the stream, calculate the concentration of Ca21 in ppm downstream of the second plant.

It took 25.06 60.05 mL of a sodium hydroxide solution to titrate a 0.4016-g sample of KHP (see Exercise 77). Calculate the concentration and uncertainty in the concentration of the sodium hydroxide solution. (See Appendix 1.5.) Neglect any uncertainty in the mass.

Tris(pentafluorophenyl)borane, commonly known by its acronym BARF, is frequently used to initiate polymerization of ethylene or propylene in the presence of a catalytic transition metal compound. It is composed solely of C, F, and B; it is 42.23% C and 55.66% F by mass. a. What is the empirical formula of BARF? b. A 2.251-g sample of BARF dissolved in 347.0 mL of solution produces a 0.01267-M solution. What is the molecular formula of BARF?

In a 1-L beaker, 203 mL of 0.307 M ammonium chromate was mixed with 137 mL of 0.269 M chromium(III) nitrite to produce ammonium nitrite and chromium(III) chromate. Write the balanced chemical equation for the reaction occurring here. If the percent yield of the reaction was 88.0%, what mass of chromium(III) chromate was isolated?

The vanadium in a sample of ore is converted to VO21. The VO21 ion is subsequently titrated with MnO4 2 in acidic solution to form V(OH)4 1 and manganese(II) ion. The unbalanced titration reaction is MnO4 2 1aq2 1 VO21 1aq2 1 H2O1l2 h V1OH2 4 1 1aq2 1 Mn21 1aq2 1 H1 1aq2 To titrate the solution, 26.45 mL of 0.02250 M MnO4 2 was required. If the mass percent of vanadium in the ore was 58.1%, what was the mass of the ore sample? Hint: Balance the titration reaction by the oxidation states method.

The unknown acid H2X can be neutralized completely by OH2 according to the following (unbalanced) equation: H2X1aq2 1 OH2 1aq2 h X22 1aq2 1 H2O1l2 The ion formed as a product, X22, was shown to have 36 total electrons. What is element X? Propose a name for H2X. To completely neutralize a sample of H2X, 35.6 mL of 0.175 M OH2 solution was required. What was the mass of the H2X sample used?

Three students were asked to find the identity of the metal in a particular sulfate salt. They dissolved a 0.1472-g sample of the salt in water and treated it with excess barium chloride, resulting in the precipitation of barium sulfate. After the precipitate had been filtered and dried, it weighed 0.2327 g. Each student analyzed the data independently and came to different conclusions. Pat decided that the metal was titanium. Chris thought it was sodium. Randy reported that it was gallium. What formula did each student assign to the sulfate salt? Look for information on the sulfates of gallium, sodium, and titanium in this text and reference books such as the CRC Handbook of Chemistry and Physics. What further tests would you suggest to determine which student is most likely correct?

You have two 500.0-mL aqueous solutions. Solution A is a solution of a metal nitrate that is 8.246% nitrogen by mass. The ionic compound in solution B consists of potassium, chromium, and oxygen; chromium has an oxidation state of 16 and there are 2 potassiums and 1 chromium in the formula. The masses of the solutes in each of the solutions are the same. When the solutions are added together, a blood-red precipitate forms. After the reaction has gone to completion, you dry the solid and find that it has a mass of 331.8 g. a. Identify the ionic compounds in solution A and solution B. b. Identify the blood-red precipitate. c. Calculate the concentration (molarity) of all ions in the original solutions. d. Calculate the concentration (molarity) of all ions in the final solution.

Tell whether the following compounds are ortho-, meta-, or para-disubstituted: (a) CH (b) (c) Cl 3 NO2 Br SO3H OH

Give IUPAC names for the following compounds: (a) (b) (c) (d) (e) (f) Cl Cl CH3 NO2 CH2CH3 O2N CH3 CH3 H3C CH3 Cl Br CH3 CH2CH2CHCH3 NH2

Draw structures corresponding to the following IUPAC names: (a) p-Bromochlorobenzene (b) p-Bromotoluene (c) m-Chloroaniline (d) 1-Chloro-3,5-dimethylbenzene

Pyridine is a flat, hexagonal molecule with bond angles of 120. It undergoes substitution rather than addition and generally behaves like benzene. Draw a picture of the p orbitals of pyridine to explain its properties. Check your answer by looking ahead to Section 15-5.

To be aromatic, a molecule must have 4n 1 2 p electrons and must have a planar, monocyclic system of conjugation. Cyclodecapentaene fulfills one of these criteria but not the other and has resisted all attempts at synthesis. Explain.

Draw the five resonance structures of the cyclopentadienyl anion. Are all carboncarbon bonds equivalent? How many absorption lines would you expect to see in the 1H NMR and 13C NMR spectra of the anion?

Cyclooctatetraene readily reacts with potassium metal to form the stable cyclooctatetraene dianion, C8H8 22. Why do you suppose this reaction occurs so easily? What geometry do you expect for the cyclooctatetraene dianion? 2 2 K 2 K +

The relative energy levels of the five p molecular orbitals of the cyclopentadienyl system are similar to those in benzene. That is, there is a single lowestenergy MO, above which the orbitals come in degenerate pairs. Draw a diagram like that in Figure 15-5, and tell which of the five orbitals are occupied in the cation, radical, and anion.

Thiophene, a sulfur-containing heterocycle, undergoes typical aromatic substitution reactions rather than addition reactions. Why is thiophene aromatic? Thiophene

Draw an orbital picture of furan to show how the molecule is aromatic. Furan

Thiamin, or vitamin B1, contains a positively charged five-membered nitrogen sulfur heterocycle called a thiazolium ring. Explain why the thiazolium ring is aromatic. Thiamin H3C CH3 OH NH2 N +N N S Thiazolium ring

Azulene, a beautiful blue hydrocarbon, is an isomer of naphthalene. Is azulene aromatic? Draw a second resonance form of azulene in addition to that shown. Azulene

How many electrons does each of the four nitrogen atoms in purine contribute to the aromatic p system? Purine

Give IUPAC names for the following substances (red 5 O, blue 5 N): (a) (b)

All-cis cyclodecapentaene is a stable molecule that shows a single absorption in its 1H NMR spectrum at 5.67 d. Tell whether it is aromatic, and explain its NMR spectrum.

1,6-Methanonaphthalene has an interesting 1H NMR spectrum in which the eight hydrogens around the perimeter absorb at 6.9 to 7.3 d, while the two CH2 protons absorb at 20.5 d. Tell whether it is aromatic, and explain its NMR spectrum.

The following molecular model is that of a carbocation. Draw two resonance structures for the carbocation, indicating the positions of the double bonds.

Azulene, an isomer of naphthalene, has a remarkably large dipole moment for a hydrocarbon (m 5 1.0 D). Explain, using resonance structures.

Give IUPAC names for the following compounds: (a) (b) (c) (d) (e) F (f) NO2 NO2 CO2H Br NH2 Cl Br H3C CH3 CHCH2CH2CHCH3 CH3 CH3 Br CH2CH2CH3

Draw structures corresponding to the following names: (a) 3-Methyl-1,2-benzenediamine (b) 1,3,5-Benzenetriol (c) 3-Methyl-2-phenylhexane (d) o-Aminobenzoic acid (e) m-Bromophenol (f) 2,4,6-Trinitrophenol (picric acid)

Draw and name all possible isomers of the following: (a) Dinitrobenzene (b) Bromodimethylbenzene (c) Trinitrophenol

Draw and name all possible aromatic compounds with the formula C7H7Cl.

Draw and name all possible aromatic compounds with the formula C8H9Br. (There are 14.)

Propose structures for aromatic hydrocarbons that meet the following descriptions: (a) C9H12; gives only one C9H11Br product on substitution of a hydrogen on the aromatic ring with bromine (b) C10H14; gives only one C10H13Cl product on substitution of a hydrogen on the aromatic ring with chlorine (c) C8H10; gives three C8H9Br products on substitution of a hydrogen on the aromatic ring with bromine (d) C10H14; gives two C10H13Cl products on substitution of a hydrogen on the aromatic ring with chlorine

Look at the three resonance structures of naphthalene shown in Section 15-6, and account for the fact that not all carboncarbon bonds have the same length. The C1C2 bond is 136 pm long, whereas the C2C3 bond is 139 pm long.

Anthracene has four resonance structures, one of which is shown. Draw the other three.

Phenanthrene has five resonance structures, one of which is shown. Draw the other four.

Look at the five resonance structures for phenanthrene (Problem 15-26), and predict which of its carboncarbon bonds is shortest.

In 1932, A. A. Levine and A. G. Cole studied the ozonolysis of o-xylene and isolated three products: glyoxal, 2,3-butanedione, and pyruvaldehyde: Glyoxal 1. O3 2. Zn 2,3-Butanedione Pyruvaldehyde CH3 CH3 H C C H + + O O CH3 C C CH3 O O CH3 C C H O O In what ratio would you expect the three products to be formed if o-xylene is a resonance hybrid of two structures? The actual ratio found was 3 parts glyoxal, 1 part 2,3-butanedione, and 2 parts pyruvaldehyde. What conclusions can you draw about the structure of o-xylene?

3-Chlorocyclopropene, on treatment with AgBF4, gives a precipitate of AgCl and a stable solution of a product that shows a single 1H NMR absorption at 11.04 d. What is a likely structure for the product, and what is its relation to Hckels rule? 3-Chlorocyclopropene

Draw an energy diagram for the three molecular orbitals of the cyclopropenyl system (C3H3). How are these three molecular orbitals occupied in the cyclopropenyl anion, cation, and radical? Which of the three substances is aromatic according to Hckels rule?

Cyclopropanone is highly reactive because of its large amount of angle strain. Methylcyclopropenone, although even more strained than cyclopropanone, is nevertheless quite stable and can even be distilled. Explain, taking the polarity of the carbonyl group into account. Cyclopropanone Methylcyclopropenone

Cycloheptatrienone is stable, but cyclopentadienone is so reactive that it cant be isolated. Explain, taking the polarity of the carbonyl group into account. Cycloheptatrienone Cyclopentadienone

Which would you expect to be most stable, cyclononatetraenyl radical, cation, or anion?

How might you convert 1,3,5,7-cyclononatetraene to an aromatic substance?

Calicene, like azulene (Problem 15-17), has an unusually large dipole moment for a hydrocarbon. Explain, using resonance structures. Calicene

Pentalene is a most elusive molecule that has been isolated only at liquid-nitrogen temperature. The pentalene dianion, however, is well known and quite stable. Explain. Pentalene Pentalene dianion

Indole is an aromatic heterocycle that has a benzene ring fused to a pyrrole ring. Draw an orbital picture of indole. (a) How many p electrons does indole have? (b) What is the electronic relationship of indole to naphthalene? Indole

Ribavirin, an antiviral agent used against hepatitis C and viral pneumonia, contains a 1,2,4-triazole ring. Why is the ring aromatic? C O O OHOH NH2 N HOCH2 N Ribavirin 1,2,4-Triazole ring N

Compound A, C8H10, yields three substitution products, C8H9Br, on reaction with Br2. Propose two possible structures for A. The 1H NMR spectrum of A shows a complex four-proton multiplet at 7.0 d and a sixproton singlet at 2.30 d. What is the structure of A?

What is the structure of a hydrocarbon that has M1 5 120 in its mass spectrum and has the following 1H NMR spectrum? 7.25 d (5 H, broad singlet); 2.90 d (1 H, septet, J 5 7 Hz); 1.22 d (6 H, doublet, J 5 7 Hz)

Propose structures for compounds that fit the following descriptions: (a) C10H14 1H NMR: 7.18 d (4 H, broad singlet); 2.70 d (4 H, quartet, J 5 7 Hz); 1.20 d (6 H, triplet, J 5 7 Hz) IR: 745 cm21 (b) C10H14 1H NMR: 7.0 d (4 H, broad singlet); 2.85 d (1 H, septet, J 5 8 Hz); 2.28 d (3 H, singlet); 1.20 d (6 H, doublet, J 5 8 Hz) IR: 825 cm21

On reaction with acid, 4-pyrone is protonated on the carbonyl-group oxygen to give a stable cationic product. Using resonance structures and the Hckel 4n 1 2 rule, explain why the protonated product is so stable. O O O O + 4-Pyrone H+

Bextra, a COX-2 inhibitor once used in the treatment of arthritis, contains an isoxazole ring. Why is the ring aromatic? S OO H2N CH3 O Bextra Isoxazole ring

N-Phenylsydnone, so-named because it was first studied at the University of Sydney, Australia, behaves like a typical aromatic molecule. Explain, using the Hckel 4n 1 2 rule. N-Phenylsydnone

Show the relative energy levels of the seven p molecular orbitals of the cycloheptatrienyl system. Tell which of the seven orbitals are filled in the cation, radical, and anion, and account for the aromaticity of the cycloheptatrienyl cation.

1-Phenyl-2-butene has an ultraviolet absorption at lmax 5 208 nm ( 5 8000). On treatment with a small amount of strong acid, isomerization occurs and a new substance with lmax 5 250 nm ( 5 15,800) is formed. Propose a structure for this isomer, and suggest a mechanism for its formation.

Propose structures for aromatic compounds that have the following 1H NMR spectra: (a) C8H9Br IR: 820 cm21

(b) C9H12 IR: 750 cm21 Intensity TMS 10 0123456789 ppm0123456789 ppm Chemical shift () Chem. shift 1.19 2.31 2.64 7.13 Rel. area 1.50 1.50 1.00 2.00 (c) C11H16 IR: 820 cm21 Intensity TMS 10 0123456789 ppm0123456789 ppm Chemical shift ()

Propose a structure for a molecule C14H12 that has the following 1H NMR spectrum and has IR absorptions at 700, 740, and 890 cm21: Intensity TMS 10 0123456789 ppm0123456789 ppm Chemical shift () Chem. shift 5.41 7.31 Rel. area 1.0

The proton NMR spectrum for a compound with formula C10H12O2 is shown below. The infrared spectrum has a strong band at 1711 cm21. The normal carbon-13 NMR spectral results are tabulated along with the DEPT-135 and DEPT-90 information. Draw the structure of this compound. Normal Carbon DEPT-135 DEPT-90 29 ppm Positive No peak 50 Negative No peak 55 Positive No peak 114 Positive Positive 126 No peak No peak 130 Positive Positive 159 No peak No peak 207 No peak No peak 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 C10H12O2 1.91 2.01 3.13 2.15 3.01 Chemical shift ()

The proton NMR spectrum of a compound with formula C6H5NCl2 is shown. The normal carbon-13 and DEPT experimental results are tabulated. The infrared spectrum shows peaks at 3432 and 3313 cm21 and a series of medium-sized peaks between 1618 and 1466 cm21. Draw the structure of this compound. Normal Carbon DEPT-135 DEPT-90 118.0 ppm Positive Positive 119.5 No peak No peak 128.0 Positive Positive 140.0 No peak No peak 7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 C6H5NCl2 Proton spectrum 1.96 0.99 2.13 Chemical shift ()

Aromatic substitution reactions occur by addition of an electrophile such as Br1 to an aromatic ring to yield an allylic carbocation intermediate, followed by loss of H1. Show the structure of the intermediate formed by reaction of benzene with Br

The substitution reaction of toluene with Br2 can, in principle, lead to the formation of three isomeric bromotoluene products. In practice, however, only o- and p-bromotoluene are formed in substantial amounts. The meta isomer is not formed. Draw the structures of the three possible carbocation intermediates (Problem 15-51), and explain why ortho and para products predominate over meta products.

Consider the aromatic anions below and their linear counterparts. Draw all of the resonance forms for each. What patterns emerge? (a) (b) H + + H2C CH2 H2C N NH

After the reaction below, the chemical shift of Ha moves downfield from 6.98 ppm to 7.30 ppm. Explain. Pd CH3O Ha Ha OCH3 N N CH3O Ha Ha OCH3 N N

The compound below is the product initially formed in a Claisen rearrangement (Section 18-4). This product is not isolated, but tautomerizes to its enol form. Give the structure of the enol and provide an explanation as to why the enol tautomer is favored. H ?

Azo dyes are the major source of artificial color in textiles and food. Part of the reason for their intense coloring is the conjugation from an electron-donating group through the diazo bridge (]N5N]) to an electron-withdrawing group on the other side. For the azo dyes below, draw a resonance form that shows how the electron-donating group is related to the electron-withdrawing group on the other side of the diazo bridge. Used curved arrows to show how the electrons are reorganized. (a) (b) NaO3S N Methyl Orange N N O2N H2N SO3Na N C.I. Acid Red 74