Fundamentals of Chemistry
Fundamentals of Chemistry CHEM 116
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Acids Bases Electrol tes Net Ionic E nations Solnbili l CHEM 116 Dr Babb s Sections Lecture Problem Sheets and Molar39 o Ions in Soln De ne the following terms strong acid strong base weak acid weak base strong 39 39J weak 39 J soluble insoluble and solubility List the seven strong acids De ne the following types of solutions saturated unsaturated and supersaturated What types of substances can be classi ed as strong electrolytes weak electrolytes non electrolytes List the solubility rules and use them to determine whether the substances listed below are soluble or insoluble in water 14 4 AgNO3 BaI2 PbSO4 NaZCO3 SrNO32 FeOH3 CaCl2 AgOH PbC2H3022 NH43PO4 FeBr3 PbC1042 ngBr2 K3PO4 CaS 04 M gCO3 AgCl BaSO4 CuCl CaS FeZS3 What are the three types of equations that can be written for any chemical reaction Predict products and write Net Ionic Equations for the following aqueous reactions A FeBr3 AgC2H302 F HClO BaOH2 B NH4ZSO4 BaClz G Na2C03 H2804 C HNO3 CsC2H302 H NH42CO3NaOH D HN02 CsC2H302 1 FeNO33 NH3 H20 E HClO4 BaOH2 What is the concentration of each ion in a 025 M CaCl2 solution How many moles of acetate ion are present in 300mL 0f0 100 M PbC2H3022 How many grams of AlCl3 are needed to prepare 500mL ofa solution that is 075M in the chloride ion What volume in mL 0f0l5 M Na3PO4 will provide 0025 mol Na If 100g NaCl is added to 300 mL of 026 M Na3P04 what is the molarity of Na in the resulting solution When 250mL 0f020 M BaCl2 is mixed with 350 mL 0f020 M NaCl what is the molarity of chloride ion in the nal solution Properties of Solutions and Concentration Units 1 1 l2 l3 l4 De ne the followingterms homogeneous mixture heterogeneous mixture solution colloid and suspension Are the following mixtures solutions Identify the solute and solvent and the physical state of each 14 karat gold mixture of Au and Ag Brass mixture of Zn and Cu What types of substances dissolve in water more readily nonpolar 0r polar substances Why Which of the following would be more soluble in hexane C6H14 than in water C8H18 CH3OH CaBr2 Wax C20H42 NH3 HCl 6 6 HC2H3O2 Write the equations used to calculate the following concentration units for solutions A Molarity M Mole Fraction X A Seawater F Milk B CocaCola soda water G Paint C Air H Italian dressing D E B Weight Percent Wt D Molality m 1 Part per billion ppb E Normality 2 Part per million ppm 16 The values of which of the concentration units depend on temperature 17 A solution is made by dissolving 200 g of CaCl2 in 500 g of water Calculate the weight percent mole fraction molality and molarity of the solution Assume that the density of the solution is the same as the density of pure water 18 A A glycerolwater solution is 400 ww glycerol C3H803 and has a density of 1101 gmL Calculate the molality molarity and mole fraction of glycerol in this solution B A solution is 50 m NaCl What is the mole fraction of NaCl in the solution 19 A sample of hard water has 15 g Cal2 in every 500 ml of water Calculate the molarity molality and ppm of Cal2 in the hard water 20 What effect does temperature have on the solubility of a solid in liquid 21 The dissolution of CuSO4 in water is endothermic Will the solubility of CuSO4 increase or decrease as temperature is increased 22 The dissolution of SrSO4 in water is exothermic Will the solubility of SrSO4 increase or decrease as temperature is decreased 23 What effect does pressure have on the solubility of a solid in a liquid Why 24 What effect does temperature have on the solubility of a gas in a liquid 25 What effect does pressure have on the solubility of a gas in a liquid State Henry s Law What is the value of the Henry s law constant if 54 g of gaseous acetylene will dissolve in 10 L of liquid acetone at a pressure of 20 atm What is the solubility of acetylene in acetone at 12 atm Colligative Progerties 26 List the four colligative properties Does the value of a colligative property depend on the identity of the solute What does the value of the colligative property depend on 27 Which has a higher vapor pressure pure water or a sugar solution State the form of Raoult s Law used to calculate the vapor pressure of a solution State the form of Raoult s Law used to calculate the vapor pressure lowering of a solution 28 A Calculate the vapor pressure and the vapor pressure lowering of a solution made by dissolving 200g ofsolid glucose C6H1206 in 5000 g ofwater The vapor pressure of pure water at 37 C is 471 torr B Calculate the vapor pressure of a solution made by dissolving 50 g CaCl2 in 500 g water at 37 C 29 Ifboth the solute and solvent are volatile then both will contribute to the vapor pressure of the solution What form of Raoult s law must be used to calculate the vapor pressure of the solution 30 In a solution of ethanol and water the mole fraction of water is 025 Ifthe vapor pressure of water and ethanol at 25 C are 238 mm Hg and 612 mm Hg respectively what is the vapor pressure of the solution Would you expect this ethanolwater solution to display negative or positive deviations from Raoult s law 31 Which has the higher boiling point pure water or salt water State the equation used to calculate the change in the boiling point of a solution 32 Which has the higher freezing point pure water or salt water State the equation used to calculate the change in the freezing point of a solution 33 The molal boiling point elevation constant and the molal freezing point depression constant are properties of which substance solution solute or solvent What are the units of Kb and 40 41 42 43 44 45 46 47 What is the boiling point of a 0575 m sugar solution Kbwater052 kg Cmol What is the boiling point of a 0575 m hydrochloric acid solution A solution is made by dissolving 672 g sodium chloride in 200 g water Calculate both the freezing points and boiling points of this solution How does the liquid range of this solution compare to that of pure water Antifreeze primarily ethylene glycol C2H602 is added to car radiators to prevent freezing In 1994 the lowest winter temperature in Morgantown WV was 20 F What molality of ethylene glycol should have been present in car radiators to prevent freezing It is interesting to note that use of pure ethylene glycol would not have been sufficient since the freezing point of pure ethylene glycol is 174 C A 0100 g sample of PCB polychlorinated biphenyla known carcinogen was dissolved in 100 g carnphor The freezing point of the resulting solution was 17828 C Calculate the molecular weight of the PCB FPpure camphor17950 C Kfcamphor400 kg Cmol A Will the freezing points of the following aqueous solutions be equivalent If not which will have the highest and which the lowest freezing point Calculate the freezing point of each solution Kfwater186 kg Cmol i 050 m sugar iii 050 m AlCl3 ii 050 m NaCl iv 050 m CaCl2 B Which of the following aqueous solutions will have the highest boiling point Which will have the lowest boiling point i 040 m NaZSO4 iv ii 050 m KNO3 v iii 060 m C6H1206 sugar When 0750 mol ofsugar and 0700 mol ofNaCl are dissolved in 50X103 g ofa solvent the boiling point is elevated by 022 C Calculate the molal boiling point elevation constant Kb of the solvent A 494 g sample of K3FeCN6 was dissolved in 100 g ofwater and the freezing point ofthe resulting solution was 11 C How many ions result from the dissolution of K3FeCN6 in water Write the dissolution equation What is the freezing point of a 0500 m HF solution HF is a weak electrolyte and the percent dissociation of HF is 265 Calculate the percent dissociation of formic acid HCOZH if a 060 m solution of HCOZH freezes at 1 13 C This is problem 1420 in the Problem Book A solution of salt water is separated from pure water by a semipermeable membrane permeable to the solvent but not the solute In which direction will the solvent ow What causes solvent to stop owing from the pure solvent side to the solution side Write the equation that relates the solution molarity to the osmotic pressure The formula for a low molecular weight starch is C6H1005n where n is 200 on average If 0798 g of this starch is dissolved in 1000 mL of water what is the osmotic pressure of the solution at 25 C A 200 g sample ofa protein is dissolved in 0100 L of water The osmotic pressure ofthe resulting solution is 16 mm Hg at 25 C Calculate the molar mass of the protein A 00500 M FeCl3 solution exerts an osmotic pressure of 4 16 atm at 25 C Calculate the expected and observed van t Hoff Factors for this solution A quantity of seawater is separated from a quantity of pure water by a semipermeable membrane A piston applies pressure to the seawater side such that the applied pressure is greater than the osmotic pressure What happens Note This process is called Reverse 00 39 J v 050 m HF 035 m A1C2H3023 060 m HC2H302 48 Osmosis Ifmarooned at sea you should not drink seawater as this causes dehydration to occur more rapidly From your knowledge of osmosis explain Kinetics Rate Law Reaction Order and Determination of Rate Law 49 50 51 52 59 De ne the following terms chemical kinetics and reaction rate Do all reactions proceed at the same rate Can the reaction rate be predicted from the chemical equation What are the units of the reaction rate How would you measure the reaction rate Consider the following equation 2 N205g 7gt 4 N02g 02g From the following experimental data calculate the rate of disappearance of N205 and the rates of appearances ofNO2 and 02 over the time intervals 0500 sec 5001000 sec and 10001500 sec time sec 1 2951 0 500 500 352 1000 248 1500 175 Is the reaction rate constant Ifnot what does it depend on What is the difference between AN205At and dN205dt Consider the following reaction 4 NH3g 5 02g 7gt 4 NOg 6 H20g Ifthe rate of disappearance of NH3 is 024 M sec what is the rate of disappearance of O2 and rate of appearance of H20 and NO What is the rate law for the general reaction aA bB 7gt cC dD What does the specific rate constant k depend on What is the order of a reaction Can the order of the reaction with respect to each reactant be obtained from the net reaction The rate law for the reaction below is RatekN022CO What is the order of the reaction with respect to each substance and what is the overall reaction order What will happen to the reaction rate if N02 is doubled if CO is halved What are the units on k N02g COg igt C02g NOg at 200 C The rate law for the reaction below is RatekNO202 What is the order of the reaction with respect to each substance and what is the overall reaction order What will happen to the reaction rate if NO is tripled if 02 is halved What are the units on k 2 NOg 02g 7gt 2 Noxg The rate law for the reaction below is RatekSOZSO312 What is the order of the reaction with respect to each substance and what is the overall reaction order What will happen to the reaction rate if 02 is doubled if 03 is doubled What are the units on k 2 SOzg 02g 7gt 2 SO3g using a Pt catalyst What four factors affect the rate of a reaction How does the temperature affect the reaction rate What is a catalyst and does it undergo any net change A Use the method of initial rates to find the rate law for the following reaction 2 NOClg igt 2 NOg C12g at 27 C NOCl Initial Rate of Formation of NO 030M 360X10399 Ms 060M 144X10398 Ms 090M 324X10398 Ms B Calculate the value for the specific rate constant C How much will the reaction rate increase if the initial concentration of NOCl is increased from 030M to l2M 60 A Find the rate law for the following reaction given the initial rate data below BrO339aq 5 Br39 6 Haq 7gt 3 Br2aq 3 H20l Exp 1 E1 H1 d BrO339 dt 1 010M 010M 010M 00012 Ms 2 020 M 010 M 010 M 00024 Ms 3 010 M 030 M 010 M 00035 Ms 4 020 M 010 M 015 M 00054 Ms 5 030 M 030 M 030 M B What is the numerical value of the specific rate constant What are the units of k C Calculate the initial rate of disappearance of BrO339 for Exp 5 Kinetics Inte rated F arm of Rate Law 61 Give the integrated form of a zeroth order reaction De ne the halflife and nd the halflife for a general zeroth order reaction Is the half life constant For a zeroth order reaction what type of plot will yield a straight line 62 Give the integrated form of a first order reaction Find the halflife for a general first order reaction Is the halflife constant For a first order reaction what type of plot will yield a straight line A A certain first order reaction has the rate law Rate kA with k00068 sec39l If the initial concentration of A is 075 M what will be the concentration of A after 1 minute What is the halflife for this reaction How much time will it take for 75 of A to react How much A will be left after the passage of three halflives What is the initial rate of the reaction 63 Give the integrated form of a second order reaction Find the halflife for a general second order reaction Is the halflife constant For a second order reaction what type of plot will yield a straight line 64 The following data were collected for the reaction 2 HIg 7gt H2g 12g at 580K Time min ml 0 300M 167 0120M 333 0061M 500 0041M 667 0031M Determine the reaction order and form of the rate law HINT Plot HI vs t lnHI vs t and 1HI vs t Calculate the numerical values of the specific rate constant and the halflife of the reaction After how much time will only 20 of the original amount of H1 remain Kinetics 1739 n Catalvsis and A 39 F auatirm 65 Define the terms elementary step and reaction mechanism Can the rate law be written directly for an elementary reaction 66 A reaction mechanism that occurs in polluted air is the following NO2 03 7gt N03 02 SLOW NO3 N02 7gt N205 FAST Write the net reaction for this process define the molecularity of each elementary step and write the rate law for this process What is happening to the N03 67 A reaction mechanism for the destruction of ozone O3 in the stratosphere is 03 7gt 02 O FAST 03 O 7gt 2 O2 SLOW Write the net reaction define the molecularity of each elementary step and write the rate law for this process Identify the intermediate 68 69 70 71 72 A reaction mechanism for the destruction of ozone by high ying aircraft is the following 03 igt 02 O NO 03 7gt N02 02 N02O 7gtNO02 Write the net reaction and de ne the molecularity of each elementary step Identify any reaction intermediates and catalysts De ne the followingterms transition state and activation energy On amolecular level how does an increase in temperature lead to an increase in reaction rate Give the Arrhenius equation Show how the Arrhenius equation can be used to calculate the activation energy and preeXponential factor The specific rate constant for the formation of H1 was measured at two different temperatures Calculate the numerical values of the activation energy and preeXponential factor Calculate the value of the specific rate constant at 427 C H2 12 7gt 2 HI kglMs Temp K 27 X 104 600 35 X 10393 650 The following rate constants were found for the decomposition of N205 at four different temperatures kgls Temng 4 8 X 104 450 8 8 X 104 5 00 l 6 X 10393 5 50 2 8 X 10393 Make a plot of lnk vs 1 T Calculate the activation energy and preeXponential factor from the plot What is the value of the specific rate constant at 1000 C How does a catalyst increase the rate of a reaction Is the reaction mechanism the same in the presence of a catalyst Chemical Equilibrium Introduction to K and K E 73 74 75 76 77 78 79 Define the following terms equilibrium equilibrium constant expression and equilibrium constant Do all reactions go 100 to completion such that all reactants react to form products Are the concentrations of reactants and products changing at equilibrium In a chemical reaction once equilibrium is established it is referred to as a dynamic equilibrium What does this mean At equilibrium how are the rates of the forward and reverse reactions related For the general elementary reaction below write the rate law for the forward reaction Forward Rate and the rate law for the reverse reaction Reverse Rate Derive the equilibrium constant K and equilibrium constant expression K by setting the Forward Rate Reverse Rate aA bB lt7gt cC dD Does the numerical value of the equilibrium constant K depend on temperature Consider the equation below What does the value of Kc tell you about the relative values of kf and kT What does the value of Kc tell you about the concentrations of products and reactants at equilibrium COC12g lt7gt COg C12g Kc46X10393 Consider the equation below What does the value of Kc tell you about the relative values 80 81 82 83 84 85 86 87 88 89 of kf and kT What does the value of Kc tell you about the concentrations of products and reactants at equilibrium PC13g C12g lt7gt PC15g Kc41 When Kc is large Kgt103 how do the concentrations of reactants and products compare When Kc is small Klt10393 how do the concentrations of reactants and products compare When Kc is intermediate 10393ltKlt103 how do the concentrations of reactants and products compare Write the equilibrium constant expressions for the chemical reactions below A 4NH3g 502g lt7gt 4N0 g 6H20g K B 3Fes 4H20g lt7gt Fe3O4s 4H2g Kc C COC12g lt7gt COg C12g Kc D PCl3g Clzg lt7gt PC15g Kc E NH3aq H20l lt7gt NH4aq OH39aq Kc F H20s lt7gt H20g Kc G 2NaHCO3s lt7gt Na2C03s H20l C02g Kc Are pure solids pure liquids and solvents included in the equilibrium constant expression Why not Given the chemical reaction below calculate the numerical value of the equilibrium constant for the reactions in A B C and D N2g 3 H2g lt7gt 2 NH3g Kc 41X108 at 25 C 2 NH3g lt7gt N2g 3 H2g K5 3 we 9 H2g lt7gt 6 NH3g K5 12 N2g 32 H2g lt7gt NH3g NH3g lt7gt 12 N2g 32 H2g Kc Write the equilibrium constant expression K in terms of partial pressures for the general reaction aAg bBg 7gt cCg dDg where a b c d are coefficients Write the equilibrium constant expressions K for the reactions below A 2 302g 02g lt7gt 2 303g B we 3 H2g lt7gt 2 NH3g C 4 NH3g 5 02g lt7gt 4 NO g 6 H20g For the reaction in 85A Kc28X102 at atemperature of 727 C What is the numerical value of K What is the general mathematical equation that can be usedto calculate Kc from KP Kc from K Calculate the equilibrium constant in terms of partial pressures K for the reaction below COg 3 H2g lt7gt CH4g H20g Kc 391 at 927 C Calculate the equilibrium constant in terms of concentrations Kc for the reaction below COg H20g lt7gt C02g H2g KP 058 at 727 C Under what conditions will Kc and Kp be equal have the same value Kc U0wgt Chemical Equilibrium Reaction Quotient and Concentration Problems 90 91 What is the form of the reaction quotient QC What concentrations are used to calculate the numerical value of the reaction quotient Consider the reaction below with the given initial concentrations of products and reactants Is the reaction already at equilibrium Ifnot which way will it proceed to attain equilibrium HINT Calculate Qc and compare its value to Kc COg 3 H2g lt7gt CH4g H20g Kc 391 at 927 C 92 93 94 95 96 97 98 Initial 00200M 00200M 000100M 000100M If Qc is greater than Kc which way will the reaction proceed in order to attain equilibrium left to right or right to left If Qc is less than Kc which way will the reaction proceed in order to attain equilibrium left to right or right to left Ich is equal to Kc which way will the reaction proceed in order to attain equilibrium left to right or right to left A 100 Lvessel contains l5X10393 mol CO2 and 55X10392 mol ofCO Some solid carbon Cs is added and temperature is raised to 1000 C Will more COg form The reaction is shown below HINT Calculate Qc and compare it to Kc C02g Cs lt7gt 2 COg Kcl 17 at 1000 C Consider the reaction given below 2 NOBrg lt7gt 2 NOg Br2g Kc307X104 at 24 C For each of the following compositions describe in which direction the reaction will go to reach equilibrium NOBr00610 M C NO00151 M Brz00108 M B NOBr0 l 15 M NO00169 M Brz00142 M Calculate the missing concentrations and the numerical value of Kc for the following NOBr0500 M NO00170 M Brz00140 M 2IClg lt7gt 12g C12g Kc Initial 0 022M 022M Change At Eq 009M B H2g 12g lt7gt 2H1g K5 Initial 0 0 5000M Change 0730M At Eq C 3A 2B lt7gt C 2D Kc Initial 600M 200M 100M 0 Change 050M At Eq If 050 mol PCl5 is injected into a 20L vessel what will be the equilibrium concentrations of all species PC15g lt7gt PCl3g C12g Kcl8 at 250 C Initially a mixture contains 0850 mol each of N2 and O2 in an 800 L vessel Calculate the equilibrium concentration of gaseous NO N2g 02g lt7gt 2 NOg Kc00123 Consider the reaction below which is already at equilibrium Calculate the partial pressures of NO2 and N204 when the total pressure is increased to 20 atm 2 N02g ltigt N204g At Eq 025 atm 025 atm Ch emical E guilibrium Le Ch atelier s Princigle 99 State Le Chatelier s Principle List the types of stresses that can be applied to a system at equilibrium 100 101 102 103 104 105 106 107 108 109 110 Why does the addition of a catalyst to an equilibrium mixture not change the equilibrium Why does an increase of pressure due to addition of an inert gas not change the equilibrium concentrations of reactants and products Ifthe temperature is changed does the value of Kc change Why Consider the reaction below 2M n At Eq 026M 009M 009M What will happen in which direction will the reaction proceed if the following changes occur A 074 M ICl is added B 074 M I2 is added C All of the C12 is removed Consider the reaction below which is at equilibrium BaSO4s lt7gt BaOs SO3g What will happen if more solid BaSO4 is added more solid BaO is added For a reaction at equilibrium the pressure is increased by decreasing the volume Will the equilibrium concentrations of species be altered Is the numerical value of Kc or Kp changed Consider the reaction below which has already attained equilibrium N20g N02g lt7gt 3 NOg Kc14X103910 at 200 C Which way will the reaction proceed to reach equilibrium if the pressure is increased by decreasing the volume For the reaction COg H20g lt7gt H2g C02g Will a decrease in pressure by increasing volume alter the equilibrium concentrations of all species A certain reaction is exothermic AH negative What happens to the numerical value of Kc if the temperature is increased if the temperature is decreased A certain reaction is endothermic AH positive What happens to the numerical value of Kc if the temperature is increased if the temperature is decreased Consider the reaction below which has already attained equilibrium N2H4g H2g lt7gt 2 NH3g AH1876 Id In which direction will the reaction proceed if the temperature is increased Consider the reaction below which has already attained equilibrium N2g 02g lt7gt 2 NOg AH181 k In which direction will the reaction proceed if the temperature is increased Kc0 12 AcidBase Theories and Coniugate AcidBase Pairs 111 112 113 De ne the following terms Arrhenius acid Arrhenius base Lewis acid Lewis base BronstedLowry acid and BronstedLowry base Identify the Lewis acids and bases in the following reactions BC13NH3 lt7gt Cl3BNH3 B H H20 lt7gt H3O C H OH39 lt7gt H20 D Ag 2NH3 lt7gt AgNH32 Identify the BronstedLowry acids and bases in the following reactions HCO339 H20 lt7gt HZCO3 OH39 HCO339 H20 lt7gt CO3392 H20 HPO4392 H2P0439 lt7gt PO4393 H3PO4 HCO339 NaOH lt7gt CO3392 H20 Nal cow 114 115 116 117 118 119 Does Hl exist alone in solution How is Hl usually written in acidbase equilibrium What is a conjugate acidbase pair How does an acid differ from its conjugate base How does a base differ from its conjugate acid For the reaction below identify the conjugate acidbase pairs HC2H302aq H20 lt gt C2H302aq l H3Oaq Give the conjugate acid and conjugate base of each of the following species NH3 HSO439 CO3392 and H20 Does a strong acid have a strong or weak conjugate base Does a weak acid have a strong or weak conjugate base Does a strong base have a strong or weak conjugate acid Does a weak base have a strong or weak conjugate acid In an acidbase reaction to tell which way the equilibrium lies we look at the relative strengths of the two bases involved Which base gets the H1 the stronger or the weaker base Which way does the equilibrium lie for the following two reactions A HCl H20 lt7gt H3O Cl39 B HC2H302aq H20 lt7gt C2H30239aq H3Oaq Km 2H 20H K j and K 5 Calculation of 2H for Strong and Weak Acids and Bases 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 Write the reaction for the dissociation of water Write the form for the ion product constant of water KW What does the value of KW depend on What are the equilibrium concentrations of H301 and OH39 in pure water Define an acidic basic and neutral solution in terms of the concentrations of H301 and OH39 If H3O5X10392 M what is the OH39 If OH395X10395 M what is the H3O Write the equations used to calculate pH pOH and pKW Write the equation that relates pH pOH and pKW ApHgt7 indicates what type of solution acidic basic or neutral A pHlt7 indicates what type of solution acidic basic or neutral A pH7 indicates what type of solution A A pH5 17 indicates what type of solution acidic basic or neutral A pOH89 indicates what type of solution acidic basic or neutral A pH7 indicates what type of solution B Which ofthe solutions shown below is basic A solution with i pH65 iii H3O1X10399 ii pOH55 iv OH391X10399 What is K A Write the equation that goes along with K A for HCl and HC2H302 What does KA tell us about the strength of an acid If KA is small 103 is the acid weak or strong What is KB Write the equation that goes along with KB for NH3 What does KB tell us about the strength ofa base If KB is small 103 is the base weak or strong Calculate the H3O OH39 pH and pOH for a 025 M HClO4 solution Calculate the H301 OH39 pH and pOH for a 00050 M BaOH2 solution Calculate the pH ofa 10X10399 M HCl solution Calculate the pH ofa 50X103910 M CaOH2 solution Calculate the H301 OH39 pH pOH and percent ionization for a 0025 M HF solution K AHF3 5 X104 The weak acid formic acid HCOOH has a pH of 2 14 when the concentration of HCOOH is 030 M What is the value for the aciddissociation constant KA and what is the percent dissociation of the HCOOH Calculate the H3O OH39 pH pOH and percent ionization for a 075 M NH3 solution KBNH318X10395 A Write all of the equilibrium equations established in a solution of 025 M HZSO3 and calculate the pH ofthe solution KA115X10392 KA263X10398 B Write all of the equilibrium equations established in a solution of 025 M H3PO4 and calculate the pH ofthe solution KA175X10393 KA262X10398 KA348X103913 H lgdrollgsis 0t Salts 136 When a salt is dissolved in water this process is called hydrolysis of the salt is the pH of the resulting solution always neutral 137 The general formula for formation of the salt is ACID BASE 7gt SALT H20 Where does the anion of the salt come from the acid or the base Where does the cation of the salt come from the acid or the base 138 A salt that contains the cation from a strong base and the anion from a strong acid will dissolve in water to give a neutral solution Explain why using NaCl 139 A salt that contains the cation of a weak base and the anion from a strong acid will dissolve in water to give an acidic solution Explain why using chemical equations for NH4Cl 140 A salt that contains the cation of a strong base and the anion from a weak acid will dissolve in water to give a basic solution Explain why using chemical equations for KNOZ 41 A salt that contains a small highly charged metal cation and the anion from a strong acid will dissolve in waterto give an acidic solution Explain why using chemical equations for AlCl3 142 When the following salts are dissolved in water will the resulting solutions be acidic basic or neutral A KC2H302 D NaF G ZnNO32 B NH4Br E K2C03 H FeClz C KCIO4 F AlBr3 143 To do problem 144 KB ofF39 the conjugate base ofHF is needed Show how KA for HF and KB for F39 can be related by KW 144 Calculate the pH ofa 045 M NaF solution KAHF35X10394 HINT First predict whether this solution should be acidic basic or neutral Second write the equations for dissociation of the salt and any equilibrium established Third calculate either K A or KB for the equilibrium 145 Calculate the pH of 075 M NH4ClO4 KBNH318X10395 HINT First predict whether this solution should be acidic basic or neutral Second write the equations for dissociation of the salt and any equilibrium established Third calculate either K A or KB for the equilibrium Stren th 0 Acids 146 How does the strength of binary acids consisting of H and some other nonmetal element vary within a group Why Arrange the following in order of increasing acid strength HCl HF HI and HBr Arrange the following in order of increasing acid strength HZS H2Te and H20 147 How does the strength of binary acids vary within a row Why Arrange the following in order of increasing acid strength HF H20 NH3 and CH4 148 How does the strength of oxyacids consisting of H O and some other element vary within a series Arrange the following in order of increasing acid strength HClO HClO3 HClOZ and HClO4 How does the strength of an oxyacid vary with the electronegativity of the central atom Arrange the following in order of increasing acid strength HOBr HOCl and H01 149 Which of the following equilibria lie mostly on the product side ie in an equilibrium mixture which one has product concentrations gt reactant concentrations A HF Br39 lt7gt HBr F39 D H20 H20 lt7gt OH39 H3O B NHZ39 H20 lt7gt NH3 OH39 R HBrO3 10339 lt7gt BrO339 HIO3 C HClO C10239 lt7gt ClO39 HClO2 Neutralization Common I on E tect and Bu Zen 1 50 151 152 153 154 155 156 157 158 159 160 161 When a strong acid is neutralized by a strong base is the neutralization complete Write the neutralization reaction for HNO3 and KOH What is the value of Kn equilibrium constant for neutralization Ifstoichiometric amounts of acid and base are reacted will the resulting solution be acidic basic or neutral When a weak acid is neutralized by a strong base is the neutralization complete Write the neutralization reaction for HF and KOH What is the value of Kn equilibrium constant for neutralization K AHF35X 104 If stoichiometric amounts of acid and base are reacted will the resulting solution be acidic basic or neutral When a strong acid is neutralized by a weak base is the neutralization complete Write the neutralization reaction for HClO4 and NH3 What is the value of Kn equilibrium constant for neutralization KBNH318X10395 If stoichiometric amounts of acid and base are reacted will the resulting solution be acidic basic or neutral When a weak acid is neutralized by a weak base is the neutralization complete Write the neutralization reaction for HF and NH3 What is the value of Kn equilibrium constant for neutralization K AHF3 5x 104 KBNH318X10395Ifstoichiometric amounts of acid and base are reacted will the resulting solution be acidic basic or neutral What happens to the pH of a solution of 0500 M HC2H3O2 if a strong electrolyte like NaC2H3O2 is added NOTE Addition of NaC2H3O2 adds a common ion Use Le Chatelier s principle to predict the direction of the reaction What will happen to the pH of 0500 M HC2H3O2 if NaCl is added What happens to the pH of a solution of 0500 M NH3 if a strong electrolyte like NH4Cl is added NOTE Addition of NH4Cl adds a common ion Use Le Chatelier s principle to predict the direction of the reaction What will happen to the pH of 0500 M NH3 if KNO3 is added Calculate the pH and ionization of a solution which is 0500 M HC2H3O2 and 0250 M NaC2H302 How does the pH of this solution compare to that of 0500 M HC2H302 K AHC2H30218X10395 What is a buffer solution and what is its function Ifthe following substances are mixed in equimolar amounts will a buffer solution be formed A HF and NaF NH3 and NH4C1 G HF and NaOH B HC2H3O2 and NaC2H3O2 13 HCl and KCl H NH3 and HCl C HCN and NaCN F NaOH and NaCl If equal volumes of the following solutions are mixed will a buffer solution result A 02 M HF and 01 M NaOH E 05 M NH3 and 10 M HCl B 02 M HF and 03 M NaOH F 02 M HCN and 02 M KOH C 02 M HF and 02 M NaOH G 03 M HOCl and 015 M BaOH2 D 02 M NaF and 01 M HCl H 03 M HOCl and 01 M BaOH2 Explain using the HC2H3OZNaC2H3O2 buffer system how a buffer maintains a relatively constant pH when small quantity of acid HCl or base NaOH is added A buffer solution consists of 0500 M HC2H3O2 and 0250 M NaC2H302 Calculate the pH of the resulting solution if 25x 10393 mol HClO4 is added to 500 mL of the buffer The pH of the buffer solution before addition of the HClO4 was 444 A buffer solution consists of 0500 M HC2H3O2 and 0250 M NaC2H302 Calculate the pH of the resulting solution if 0025 mol NaOH is added to 500 mL of the buffer The pH of the buffer solution before addition of the NaOH was 444 Derive the HendersonHasselbach equation for a buffer solution consisting of weak acid conjugate base HFNaF and for a buffer solution consisting of weak baseconjugate 162 163 164 165 166 167 acid NH3N H41 If the concentrations of acid and conjugate base are equal what is the pH of the buffer solution equal to A buffer solution is 025 M HNO2 and 015 M NaNOZ What is the pH of the buffer K AHNOZ4 5X 10394 A buffer solution with apH of 40 is needed in an experiment Which of the following buffer systems should be used For the chosen buffer system what concentration ratio of conjugate baseacid should be used to attain pH40 A HNOZNaNOZ KA45x104 B HC2H302NaC2H302 KA18X10395 C HCOOHNaCOOH KA18X10394 D C6H5COOHNaC6H5COO KA65X10395 E HCNNaCN IltA49x1010 F NH3NH4C1 KB18x10395 A buffer with a pH of95 is to be prepared from NH3 and NH4Cl What ratio ofbase to salt would you use KBNH3 1 8 X10395 Explain why dilution of a buffer solution does not change the pH Does a buffer work best when it s solution is dilute or concentrated ie Which has a better buffer capacity a dilute or concentrated solution What concentration ratio of acidsalt or basesalt works best for buffers A buffer solution is 010 M HC2H3O2 and 020 M NaC2H302 What is the pH of this buffer solution Calculate the pH after the addition of 00040 mol HCl to 100 ml of the buffer Calculate the pH after the addition of 00060 mol NaOH to the buffer T itratitms Titration Curves and Indicators 169 170 171 172 What is the shape of the titration curve plot of pH vs mL of added base for titration of a strong acid by a strong base In a titration 25 mL of 050 M HNO3 was titrated with 025 M KOH Calculate the pH of the resulting solution after the addition of the following volumes of base 0 mL 25 mL 50 mL and 60 mL What volume of base is needed to reach the equivalence point What species is present at the equivalence point and what is the pH at the equivalence point What is the shape of the titration curve plot of pH vs mL of added base for titration of a weak acid by a strong base In a titration 10 mL of 010 M HF was titrated with 020 M KOH Calculate the pH of the resulting solution after the addition of the following volumes ofbase 0 mL 25 mL 50 mL and 60 mL What volume of base is needed to reach the equivalence point What species is present at the equivalence point and what is the pH at the equivalence point When enough base has been added to neutralize half of the weak acid what type of system is present What is the pH halfway to the equivalence point K AHF3 5 X104 What is the shape of the titration curve plot of pH vs mL of added acid for titration of a weak base by a strong acid In a titration 20 mL of0 10 M NH3 was titrated with 020 M HCl Calculate the pH of the resulting solution after the addition of the following volumes ofacid 0 mL 50 mL 100 mL and 150 mL What volume ofacid is needed to reach the equivalence point What species is present at the equivalence point and what is the pH at the equivalence point When enough acid has been added to neutralize half of the weak base what type of system is present What is the pH halfway to the equivalence point KBNH318X10395 What is the difference between the equivalence point and the end point in a titration An indicator itself is a weak acid or base that has one color in acidic solution and a different 173 174 color in basic solution The general equilibria for an indicator can be written as follows HInaq H20 lt7gt In39aq H30aq K For phenolphthalein HIn is colorless whereas In39 is pink What is the color of the indicator in basic solution In acidic solution For phenolphthalein K A79X 1039 Around what pH will phenolphthalein change color Could phenolphthalein be used as an indicator during the titration of a strong acid with a strong base eg HCl with NaOH strong base with a weak acid eg NaOH with HC2H302 strong acid with a weak base eg HBr with NH3 Three titrations were to be carried out with the acids and bases indicated below Choose the best indicator for each titration from the following phenolphthalein K A79X 103910 methyl orange KA16 X 104 and bromothymol blue KA16 X 107 A HNO3 with NH3 B HNO3 with KOH C HClO3 with NaOH Solubilgl39 3 Product Factors A tecting Solubility and Ion Product 1 75 176 177 178 179 180 181 182 183 184 185 186 187 188 What is Ksp Write the chemical equation for dissolution of Ca3PO42 Write the solubility product constant expression for this equation How is the numerical value of KSp determined What does its value depend on A sample of PbCl2 was dissolved in water until a saturated solution was obtained until some solid PbCl2 was present The concentration of Pb2 in the solution was found to be 144X10392M Calculate the numerical value of Ksp A saturated solution of Ca3PO42 was prepared and the concentration of Cal2 was found to be 343X 10397 M Calculate the numerical value of Ksp Calculate the solubility in g L and in mol L of AgBr in water KspAgBr54X103913 Calculate the solubility in g L and in mol L of Mg3AsO42 in water KspMg3AsO4221X103920 If AgZSO4 is mixed with water to obtain a saturated solution what is the concentration of each ion in the resulting solution KspAgZSO412X10395 Calculate the solubility of BaF2 in pure water and in 030 M KF NOTE KF adds a common ion BaSO4 is only sparingly soluble with Ksp11X10391 Will addition of KZSO4 or BaCl2 change the solubility ofBaSO4 Ifso how Calculate the solubility ofBaSO4 in 010 M KZSO4 and in 025 M BaClz Will addition of an acid or a decrease in pH change the solubility of the following salts How and why A 0an D ngBrz B AgCl E MnS C PbI2 F cho3 Show using equations how addition of an acid increases the solubility of ZnCO3 Show using equations how addition of an acid increases the solubility of MnS Will addition of an acid like HCl or a decrease in pH change the solubility of FeOH3 AgOH AlOH3 and MgOH2 Show using equations how addition of an acid increases the solubility of MgOH2 A Calculate the pH of a solution saturated with MgOH2 KspMgOH256X103912 B Calculate the molar solubility of MgOH2 in pure water and in water buffered at a pH 0f 800 Will aprecipitate form if 100 mL of0075 M MgNO32 is mixed with 200 mL of0010 M Na2C03 KspMgCO368X10396 HINT Calculate the ion product or reaction quotient IP 189 190 Separations via 1 191 192 193 194 195 196 AlOH3 Metal Comglexes and Isomertsm 197 198 199 or Qsp and compare to Ksp If IPQSPKSp will a precipitate form and what type of solution is present saturated unsaturated or supersaturated If IPQSPgtKSp will a precipitate form and what type of solution is present If IPQspltKSp will a precipitate form and what type of solution is present Will a precipitate form if 500 mL of 0050 M AgC2H3O2 is mixed with 300 mL of 0010M K2S04 KspAg2SO412X10395 39 39 39 and f quot Analvviv A solution is 00015 M in each of the cations Agl Pb and ng What concentration of chloride ion must be present to precipitate as much of the ng as ngClz as possible without precipitating the chlorides of Ag and Pb KspHg2C1214X103918 KspPbC1212X10395 KspAgCl18X10391 Consider question 191 What concentration of Cl39 is needed to precipitate all of the ions but Pb What is the concentration of ng ions in the solution at this concentration of Cl39 A solution with a pH of 052 is 00010 M in each of the cations Pb Hg Mn Ni and Zn and 010 M in HZS Which of the cations will precipitate as the sul de The general equilibrium established for divalent metal cations 2 charge is MSs 2 H3Oaq lt7gt H2Saq M 2 H20 HgS Kspa2X103932 PbS K3353 X 10397 MnS K3353 X 1010 NiS Kspa8X10391 ZnS K3353 X 10392 What pH is needed to precipitate all of the Group III cations as the sul de A solution is 0500 M in each ofthe ions Ni and Crl3 and has a pH of 400 Solid NaOH is added to precipitate the hydroxides Can these two ions be separated from each other by adjusting the pH of the solution What pH is needed to precipitate as much of the Crl3 as possible without precipitating the Ni NiOH2 Ksp2 X 103915 Cr0H3 Kaf63X1039 A solutlon 1s 10X10393 M 1n each of the metal catlons Cul Pb ng and Ag Solld NaBr is added to this solution In what order will the bromides precipitate CuBr Ksp63X10399 AgBr Ksp54x103913 PbBr2 Ksp66X10396 ngBrz Ksp64X103923 A solution is 00050M in Sn and All3 and has a pH100 Solid NaOH is added to make the solution more basic Which of these metal cations will precipitate rst SnOH2 Ksp3 X 103927 Ksp20X103932 What is a coordination compound also called a metal complex What type of bonds are present between the ligands and the metal cation The ligand acts as a Lewis Base toward the metal cation so what must be present on the ligand For the following metal complex salts identify the ions or molecules within the coordination sphere of the metal cation those bonded with a coordinate covalent bond and those bonded ionically to the complex Calculate the charge on the complex ion and on the metal cation AgNH32Cl CONH36 013 K2NiCN4 NaAgCN2 CoNH35C1C12 CrH206SO4 CoNH34C12C1 Three different metal complexes consisting of C0 C139 and NH3 with the chemical formulas 200 201 202 203 204 205 206 207 208 209 210 211 212 213 CoNH36Cl3 CoNH35Cl3 and CoNH34Cl3 were isolated experimentally Reaction of the first complex with AgNO3 caused precipitation of 3 mol AgClmole complex the second two mole AgClmole complex and the third one mole AgClmole complex For each complex identify how the chloride ions are bonded Write the reaction between the complex and AgNO3 and give the best designation for the chemical formula of the complex Which of the following CoIII complexes would yield two moles of watermole of complex upon heating 1 CoNH34H20ClC12H20 III CoNH34H202 C13 11 CoNH34H202C13 IV CoNH34C122H20 De ne the following terms coordination number monodentate ligand bidentate ligand polydentate ligand and ligand donor atom What coordination numbers are possible for metal complexes Iftwo ligands are bonded to a metal cation CN2 what is the shape of the complex If four ligands are bonded to a metal cation CN4 what is the shape of the complex Ifsix ligands are bonded to a metal cation CN6 what is the shape of the complex Give some examples of monodentate ligands and identifythe ligand donor atom in each case The SCN39 and N0239 ligands have two different donor atoms Why aren t SCN39 and N0239 considered bidentate ligands Give some examples of bidentate ligands and identify the two ligand donor atoms Draw a threedimensional picture of the Coen33 complex ion Give an example of a hexadentate ligand and identify the six ligand donor atoms Draw a threedimensional picture of the CoEDTA39 complex ion What is an ionization isomer Two different complexes have the same chemical formula PtNH34C12Br2 When reacted with AgNO3 one complex precipitates 2 mole AgClmole complex while the second precipitates two mole AgBrmole complex Give the best designation for the chemical formula of each complex Are ionization isomers possible for NaAgCN2 What is a linkage isomer What ligands when present will produce linkage isomers Two different complex ions have the same chemical formula CoNH35N022 One complex ion is yellow while the other is red Account for the difference in colors What are geometric isomers diastereomers How many different geometric isomers are possible for CoNH34C12 for CoNH33Cl3 for CoNH35Cl2 In each case draw all possible geometric isomers and decide whether the resulting complex ion is polar or nonpolar The metal complex PtNH32Cl2 is square planar Are geometric isomers possible for this complex Ifso draw all possible geometric isomers identify whether the each form is trans or cis and decide whether the complex is polar or nonpolar Are geometric isomers possible for a metal complex with CN2 or for a metal complex with CN4 with a tetrahedral arrangement of ligands What are optical isomers enantiomers Define the terms chiral and achiral Consider the complex ion Coen2NH323 Are geometric isomers possible for this complex ion Ifso draw each diastereomer Are optical isomers possible for both the cis form and trans form of this complex ion Draw each enantiomer Are optical isomers possible for a metal complex with CN6 with the general formula MX3ABC where X A B and C are ligands Are optical isomers possible for the followingtetrahedral complex ions of Mn MnClzBr2392 MnCl3Br392 and MnClBrIF392 Crystal Field T heor and Colors of Metal Coleexes 214 Consider the Crystal Field Theory description of the bonding between ligand and metal 215 216 217 218 219 220 221 222 cation in metal complexes What type of attractions are presentbetween the ligand and metal cation For a metal complex with CN6 how do the incoming ligands affect the energy of the metal cation dorbitals Is the energy of all of the dorbitals affected to the same extent Which dorbitals are destabilized the most by the presence of the ligands Why For ametal complex with CN4 tetrahedral how do the incoming ligands affect the energy of the metal cation dorbitals Is the energy of all of the dorbitals affected to the same extent Which dorbitals are destabilized the most by the presence of the ligands Why For a metal complex with CN4 square planar how do the incoming ligands affect the energy of the metal cation dorbitals Is the energy of all of the dorbitals affected to the same extent Which dorbitals are destabilized the most by the presence of the ligands Why Define the crystal field splitting A0 for an octahedral complex What is meant by the following terms Weak field ligand strong field ligand high spin complex and low spin complex Give the spectrochemical series and identify weak field high spin and strong field low spin ligands Draw a crystal field energy level diagram and predict the number of unpaired electrons for the following complexes A CrH2063 G Few B CoF6393 HI FeCN6393 c CoCN6393 1 NiNH362 D TiH2063 J CrCN6393 E VH2063 K MnCN6393 F M11016 393 L NiH062 Show that for the systems d1 d2 d3 d8 d9 and d10 two different spin states high spin and low spin are not possible Show that for the systems d4d7 two different spin states are possible dependent on the field strength of the ligand What type of electronic configurations for metal cations always leads to colorless compounds For transition metal complexes to be colored how many electrons must occupy the dorbitals Predict whether or not a solution of the following compounds would be colored NaBr CuNO3 BiNO33 AsCl3 CuN032 FeC2H3023 HgCl2 KNO3 PbClO42 ZnN032 NiH206Clz SbCl3 MnNO33 39 39 nmnlovm39 andfV 39 39 i r 39 Complex Formation 223 224 225 226 Does formation of a metal complex usually increase or decrease the solubility of a salt Write the equations for the formation of the following metal complexes AgNH322 Iltf17x107 AIEOHH Kf21x1034 CuNH34 Kf11X1013 Cr OH 4 2 Kf8X1029 AgCN2l39 K 1 x 1021 ZHOH439 Kf2 8 x1015 Is AgCl more solfuble in pure water or a solution of aqueous ammonia Why Write the NET equation that shows how solid AgCl can be dissolved by aqueous ammonia to form an ammonia complex Calculate the value of the equilibrium constant for this equation KspAgCl18X10391 KfAgNH3217X107 The metal cations Cd Zn Cu Ag and Nil2 form soluble ammonia complexes of 227 228 229 230 231 232 CdNH34 ZnNH34 CuNH34 AgNH32 and NiNH36 The test for formation of an ammonia complex is to add a limited amount of ammonia and then toadd an excess of ammonia to a solution containing one of these ions Give equations for the reaction that occurs with each of these metal cations in limited and excess ammonia Amphoteric hydroxides are soluble in both acidic and basic solutions but insoluble in neutral solutions The metal cations Al Zn Pb Cr3 and Sn are amphoteric and form soluble complexes of AlOH439 ZnOH4392 PbOH4392 CrOH439 and SnOH339 at high pH pHgt10 The test for amphoteric nature is to add a limited amount of NaOH and then to add an excess of NaOH to a solution containing one of these ions Give equations for the reaction that occurs for each of these ions in limited and excess NaOH Calculate the solubility of AgBr Ksp54x 1013 in 075 M NH3 Compare the solubility of AgBr in pure water and in 075 M NH3 leAgNH32r17x107 A solution is 060 M in CuNH34 Kfl IX 1013 Calculate the concentration of free Cu and NH3 in this solution Calculate the solubility of CuOH2 in a solution of 12 M NH3 KspCuOH2l6X103919 KfCuNH34 l l X 1013 Calculate the equilibrium concentrations of Ni and NH3 in the solution when 0050 mol NiNO32 is added to 1000 mL of 10 M NH3 K NiNH36 56X108 The complex ion AgNH32Kfl7X107 is formed from a solution that is 010 M Ag and 10 M NH3 After the complex is formed the solution is made 0030 M in NaCl Will any AgCl precipitate KspAgCll8X103910 Sgontaneitlg Enth 1121 Entromg and Gibbs Free Energy 233 234 235 236 237 238 239 240 241 De ne the following terms spontaneous process and nonspontaneous process Ifa reaction is exothermic does that automatically mean that it is spontaneous in the forward direction If a reaction is endothermic does that automatically mean that it is nonspontaneous in the forward direction Given the standard heats of formation below calculate the standard enthalpy of the reaction 4 NH3g 5 02g 7gt 4 we 6 H20g AHf NOg9037 kJmol AHf H20g24l8 kJmol AHf NH3g46 l9 ldmol Define entropy S Can S have a negative value Can AS have a negative value IfAS is positive during a reaction or process is entropy increasing or decreasing during the process IfAS is negative during a reaction or process is entropy increasing or decreasing during the process Arrange the phases liquid solid and gas according to decreasing entropy Predict the sign of AS the change in entropy for the following processes H20s 7gt H20l H200 igt H20g H20g igt H20s NaCls 7gt Naaq Cl39aq FeSO4s 7gt Fe aq SO4392aq 12s igt 12aq For the reaction given in question 235 predict the sign for the entropy change AS For the reaction 2 H20g N2g 7gt N2H4l 02g predict the sign for the entropy change AS Show how the entropy of a substance depends on temperature What is the entropy of a perfectly ordered crystalline solid at absolute zero State the third law of thermodynamics Calculate the change in entropy from tabulated values of the standard molar entropies forthe mpopj 242 243 244 245 246 reaction given in Question 235 S NH3gl923 JKmol S NOg2107 JKmol S 02g2050 JKmol S H20g1887 JKmol State the second law of thermodynamics Show how the expression for Gibbs Free Energy is obtained from the second law of thermodynamics If during a reaction the total entropy of the system and surroundings ASwm is increasing what is the sign of AG and is the reaction spontaneous in the forward direction Give the equation used to calculate the Gibbs Free Energy change AG for a reaction or process What values of AG lead to spontaneous processes nonspontaneous processes For the following signs of AH and AS predict the sign of AG and decide whether or not the sign of AG will depend on temperature CASEl AH AS CASE2 AH AS CASE3 AH AS CASE4 AH AS What is the crossover temperature and how is it calculated Can a crossover temperature be calculated for CASE 2 and CASE 3 Why or why not For the reaction C2H50Hl 3 02g 7gt 2 C02g 3 H20l Calculate the standard Gibbs free energy change Decide whether the reaction is spontaneous in the forward direction Calculate at what temperature the reaction will change in behavior from spontaneous to nonspontaneous or from nonspontaneous to spontaneous ie calculate the crossover temperature kJmoll S JKmol C2H50Hl 2777 1 02g 2050 C02g 3935 2136 H20l 2858 699 Calculate the standard Gibbs Free energy AG from tabulated values of the standard Gibbs Free energy of formation AGE for the reactions below and decide whether the reaction is spontaneous or nonspontaneous in the forward direction A CH4g 4 C12g igt CCl4l 4 HClg B 2 CH3OH1 igt 2 CH4g 02g AGF kJmol AHF kJmol S JKmol CH4g 5075 00141 6063 HClg 9530 CH3OH1 1663 COg 1372 1105 1976 H20g 2286 2418 1887 H2g 0 0 1306 Csgr 0 0 57 Gibbs Free Enerng and Equilibrium 247 248 AG is the Gibbs Free Energy under nonstandard conditions How is AG different from AG Give the equation used to calculate AG from AG and Q the reaction quotient NOTE If a reaction consists of primarily gas phase reactants and products Qp should be used If a reaction consists of primarily solution phase reactant and products Qc should be used Consider the reaction below Initially a vessel contained 0500 atm COg 0150 atm H20 g and 425X10392 atm H2g Is the reaction spontaneous in the forward direction at 249 250 251 252 253 25 C at 800 C HINT Calculate the value of AG Values of AG are given in question 246 00 H20g lt7gt 00g H2g Use the facts that 139 when a reaction is at equilibrium AG0 and ii when a reaction is at equilibrium QK to derive the relationship between AG and K Consider the reaction forthe formation of the cobalt ammonia complex CoNH363 below Co3aq 6 NH3aq lt7gt CoNH363 aq Kf20X107 at 25 C A Calculate the Gibbs Free Energy under standard conditions for this reaction B IfCo3000500M NH30 10 M and CoNH363l00 M initially is the reaction spontaneous in the forward direction For the reaction PC15g lt7gt PCl3g C12g AG 372 kJ Calculate the equilibrium constant at 25 C Calculate the equilibrium constant at 200 C kJmoll S JKmol PC15g 3749 3646 PC13g 2870 3118 Clzg 2230 Forthe reaction C2H4g 3 02g 7gt 2 C02g 2 H20g AH i1323 1d Decide whether or not the reaction is spontaneous in the forward direction under the following conditions pC2H420 atm p020020 atm pC020010 atm and pH200010 atm at 25 C Under the same conditions is the reaction spontaneous in the forward direction at 750 C S JKmol C02g 2136 H20g 1887 C2H4g 2196 02g 2050 The substance P4010s is often used to adsorb water vapor in dry boxes by the following reaction 6 H20g P4010s 7gt 4 H3PO4s A Calculate AG and K at 25 C and decide whether the reaction is spontaneous in the forward direction kJmoll S JKmol H3PO4s 1279 1105 P4010s 2984 2289 H20g 2418 1887 B The P4010 is regenerated by heating the H3PO4 and removing the water To what temperature should the H3PO4 be heated ie at what temperature does the reaction become spontaneous in the reverse direction What is the value of K at this temperature C The vapor pressure ofwater at 25 C is 175 mm Hg Will the P4010 spontaneously adsorb the water vapor at 25 C Electrochemistrlg Galvanic Cells and Standard Reduction Potentials 254 255 256 Define the following terms electrochemistry electrochemical cell galvanic cell and electrolytic cell Are batteries considered to be galvanic or electrolytic cells When a copper wire is placed in an aqueous solution of AgNO3 what happens Write the Net Ionic equation for this redox reaction and decide which of the substances are being oxidized and which reduced Write the halfreactions for this redox reaction If a silver wire were placed in an aqueous solution of CuNO32 would a reaction occur Why or why not