# Chem 430 – physical chemistry i

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1. Properties of Gases

2. Thermodynamics

3. Changes of State

4. Chemical Reactions

5. Electrochemistry

6. Kinetic Theory of Gases

7. Chemical Kinetics

8. Changes of State

9. Transport Properties

Chapter 1

1. What is the error in calculating the pressure of 3.00 moles CO2 gas in a 0.250 m3 container at 500.0 K using the ideal gas law instead of van der Waals equation?

2. True or False. At the critical point the first and second derivatives of the pressure with respect to the molar volume are equal to zero.

3. True of False. Virial Equations of state assume that molecules have no volume, but do interact with one another.

4. What is a system called when neither mass or energy is exchanged with the surroundings.

5. When work is done on the system by the surroundings its’ sign is ( + or – ). (Circle one)

6. A mixture of H2 and O2 is 10.0% by mass H2, what are the mole fractions of H2 and O2?

Chapter 2

1. If heat is release by a reaction the reaction is said to be

2. 2.00 moles of an ideal monatomic gas is adiabatically expanded against a constant external pressure of 0.02704 MPa from 0.0500 m3 at 298.15 K to 0.0750 m3. What is the work (w), heat (q), the change internal energy (ΔU) and change in enthalpy (ΔH) of the system for this expansion?

3. What is the work (w), heat (q), the change internal energy (ΔU) and change in enthalpy (ΔH) of the system if the gas in Problem 3 is compressed back to it initial volume isothermally and reversibly?

4. 1.00 mole of an ideal monatomic gas is adiabatically and reversibly expanded from 0.0500 m3 at 300.0 K to 0.150 m3. What is the work (w), heat (q), the change internal energy (ΔU) and change in enthalpy (ΔH) of the system for this expansion?

5. What is the work (w), heat (q), the change internal energy (ΔU) and change in enthalpy (ΔH) of the system if the gas in Problem 4 is compressed back to it initial volume isothermally against a constant pressure of 24.0 kPa?.

6. Determine the change in enthalpy (ΔH) for the reaction,

C3H8(g) + 5 O2 –> 3 CO2(g) + 4 H2O(l)

using the heat of formation data in Table C.2 in your book.

7. When 0.3213 g of glucose was burned in a bomb calorimeter the temperature rose 7.793 K. What is the molar internal energy of combustion of glucose if the heat capacity of the calorimeter is 641J/K?

8. True or False. If an expansion is done isothermally the change in internal energy of the system will be negative.

9. If a variable is only dependent on the initial and final conditions and not the pathway it is referred to as a

10. One mole of an carbon dioxide a real gas is isothermally expanded from 0.0500 m3 at 298.15 K to 0.0750 m3. What is w for the process if you assume van der Waals equation.

11. Derive the expression for reversible work of a isothermal expansion for a virial equation in volume. (Truncate the equation after 3 terms, PVm= RT ( 1+ B/Vm + C/Vm2) )

12. Given that Cp – Cv = α2TV/κT, determine the equation for the difference between Cp and Cv for a real gas that obeys the viral equation given in Problem 2.

Chapter 3

1. One mole of an carbon dioxide a real gas is isothermally expanded from 0.0500 m3 at 298.15 K to 0.0750 m3. What is w for the process if you assume van der Waals equation.

2. Derive the expression for reversible work of a isothermal expansion for a virial equation in volume. (Truncate the equation after 3 terms, PVm= RT ( 1+ B/Vm + C/Vm2) )

3. Given that Cp – Cv = α2TV/κT, determine the equation for the difference between Cp and Cv for a real gas that obeys the viral equation given in Problem 2.

Chapter 3a

1. One mole of an ideal monatomic gas is isothermally expanded against a constant pressure of 0.03305 MPa from 0.0500 m3 at 298.15 K to 0.0750 m3. What are the DSSYS, DSSURR, and DSUNIV? (R= 8.314 Pa m3 T-1 mol-1)

2. One mole of an ideal monatomic gas is reversibly heated at constant volume from 300.0K to 400.0K. What are the DSSYS, DSSURR, and DSUNIV?

3. One mole of an ideal monatomic gas is adiabatically and reversibly expanded from 0.500 dm3 at 298.15 K to 0.750 dm3. What are the DSSYS, DSSURR, and DSUNIV?

4. If the efficiency of a Carnot Heat Engine is 0.80 and the lower temperature reservoir is at 77.32K, what is the temperature of the high temperature reservoir?

5. What are the DU, DH, DSSYS, DSSURR, and DSUNIV for one cycle of the Carnot Heat Engine in Problem 4?

6. What would you expect the sign of DSSYS to be for the irreversible process of converting water (liquid) to ice at -10oC?

7. What is the DS of mixing 4.00 mol of N2 with 1.00 mol of O2 at 300.0 K if both gases are acting ideal?

8. What is the DSRXN for the following reaction?(Use Table C.2 in the text)

2 H2(g) + O2(g) ® 2 H2O (l) : DSRXN=?

9. What is the S298 for HCl given the following data?

a=0.0009521 J K-4mol-1 Cp(16®98.36K)=16.24 J K-1mol-1

DHtrns(I®II)=1.190kJ/mol Cp(98.36®158.91K)=44.00 J K-1mol-1

DHfus(158.91)=1.992kJ/mol Cp(158.91®188.07K)=58.76 J K-1mol-1

DHvap(188.07)=1.190kJ/mol Cp(188.07®298.15K)=29.30 J K-1mol-1

10. A sample of an ideal gas occupies 0.0150 m3 at 250.0 K and 0.100 MPa. To what volume must the gas be compressed isothermally in order to reduce its entropy by 5.00J/K? What is the ΔG and ΔA for this process?

11. What is the molar Gibbs free energy of reaction (ΔGRXN) for the following reaction at 398.15 K and 100.0 bar?

2 NO (g) + O2 (g) —> 2 NO2 (g),

ΔHo298= -228.28 kJ, ΔSo298= 117.20 J/K

12. What if the difference between the CP and CV for 0.100 m3 benzene at 273K if the values for a and k are 12.4×10-4 K-1 and 9.10×10-10 Pa-1 respectively?

13. What is the fugacity coefficient for Ar at 1000. bar and 273 K if the B’ and C’ (virial coefficients) are -8.24×10-3 bar-1 and 2.33×10-6 bar-2, respectively?

Chapter 4

1. One mole of an ideal monatomic gas is isothermally expanded against a constant pressure of 0.03305 MPa from 0.0500 m3 at 298.15 K to 0.0750 m3. What are the ΔSSYS, ΔSSURR, and ΔSUNIV? (R= 8.314 Pa m3 T-1 mol-1)

2. One mole of an ideal monatomic gas is reversibly heated at constant volume from 300.0K to 400.0K. What are the ΔSSYS, ΔSSURR, and ΔSUNIV?

3. One mole of an ideal monatomic gas is adiabatically and reversibly expanded from 0.500 dm3 at 298.15 K to 0.750 dm3. What are the ΔSSYS, ΔSSURR, and ΔSUNIV?

4. If the efficiency of a Carnot Heat Engine is 0.80 and the lower temperature reservoir is at 77.32K, what is the temperature of the high temperature reservoir?

5. What are the ΔU, ΔH, ΔSSYS, ΔSSURR, and ΔSUNIV for one cycle of the Carnot Heat Engine in Problem 4?

6. What would you expect the sign of ΔSSYS to be for the irreversible process of converting water (liquid) to ice at -10oC?

7. What is the ΔSRXN for the following reaction?(Use Table C.2 in the text)

2 H2(g) + O2(g) → 2 H2O (l) : ΔRXN=?

8. What is the S298 for HCl given the following data?

a=0.0009521 J K-4mol-1 Cp(16→98.36K)=16.24 J K-1mol-1

ΔHtrns(I→II)=1.190kJ/mol Cp(98.36→158.91K)=44.00 J K-1mol-1

ΔHfus(158.91)=1.992kJ/mol Cp(158.91→188.07K)=58.76 J K-1mol-1

ΔHvap(188.07)=1.190kJ/mol Cp(188.07→298.15K)=29.30 J K-1mol-1

Chapter 4a

1. The molar volume of a certain solid is 161.0 cm3 mol-1 at 1.00 atm and 350.75 K, its melting temperature. The molar volume of the liquid at this temperature and pressure is 163.3 cm3 mol-1. At 100 atm the melting temperature changes to 351.26 K. Calculate the molar enthalpy and entropy of fusion of the solid.

2. What is the vapor pressure of water at 90.0oC if the standard boiling is 99.6oC? The enthalpy of vaporization of water is 40.656 kJ/mol?

3. What is the vapor pressure of a sample of water at 298 K when a pressure of 10.0 bar is applied externally? The vapor pressure of water at 298 without external pressure is 0.0315 bar and the molar volume of the liquid at 298 is 18.07 cm3 mol-1?

4. What is the mole fraction of water in the vapor over a solution of 2.00 moles of water and 2.00 moles of methanol at 50.0oC, if the vapor pressure of methanol and water at this temperature are 100.0 torr and 92.51 torr respectively? (Assume an ideal solution)

Chapter 5

1. A sample of an ideal gas occupies 0.0150 m3 at 250.0 K and 0.100 MPa. To what volume must the gas be compressed isothermally in order to reduce its entropy by 5.00J/K? What is the ΔG and ΔA for this process?

2. What is the molar Gibbs free energy of reaction (ΔGRXN) for the following reaction at 398.15 K and 100.0 bar?

2 NO (g) + O2 (g) —> 2 NO2 (g),

ΔHo298= -228.28 kJ, ΔSo298= 117.20 J/K

3. What if the difference between the CP and CV for 0.100 m3 benzene at 273K if the values for a and k are 12.4×10-4 K-1 and 9.10×10-10 Pa-1 respectively?

4. What is the fugacity coefficient for Ar at 1000. bar and 273 K if the B’ and C’ (virial coefficients) are -8.24×10-3 bar-1 and 2.33×10-6 bar-2, respectively?

Chapter 5a

1. What is the chemical potential of H2O2(g) at 298.15 K and 10.00 atm if it is -105.57 kJ/mol at 1.00 atm?

2. What is the ΔG, ΔH, and ΔS of mixing 4.00 mol of N2 with 2.00 mol of O2 at 300.0 K if both gases are acting ideal?

3. What is the temperature at which an 0.100 molal aqueous solution of isopropanol(C3H8O) will boil? (ΔHVAP=44.0 kJ/mol)

4. What is the molar mass of a compound if its osmotic pressure at 298K is 34.0 torr when 0.2 grams is added to 0.500 liters?

5. What is the mean concentration, inoic Strenght, mean activity coefficient and mean activity of a 0.0100 molal solution of CaCl 2 (aq) at 25 ° C? (Assume Debye Hückel Theory)

6. What is the activity coefficient of water in a mixture of 10.0 moles of water and 0.5 moles of ethanol at 50.0 oC if the partial pressure of water in this mixture at this temperature is 90.0 torr? The vapor pressure of pure water at this temperature is 92.51 torr.

Chapter 6

1. The molar volume of a certain solid is 161.0 cm3 mol-1 at 1.00 atm and 350.75 K, its melting temperature. The molar volume of the liquid at this temperature and pressure is 163.3 cm3 mol-1. At 100 atm the melting temperature changes to 351.26 K. Calculate the molar enthalpy and entropy of fusion of the solid.

2. What is the vapor pressure of water at 90.0oC if the standard boiling is 99.6oC? The enthalpy of vaporization of water is 40.656 kJ/mol?

3. What is the vapor pressure of a sample of water at 298 K when a pressure of 10.0 bar is applied externally? The vapor pressure of water at 298 without external pressure is 0.0315 bar and the molar volume of the liquid at 298 is 18.07 cm3 mol-1?

4. What is the mole fraction of water in the vapor over a solution of 2.00 moles of water and 2.00 moles of methanol at 50.0oC, if the vapor pressure of methanol and water at this temperature are 100.0 torr and 92.51 torr respectively?

Chapter 6a

1. What is the point called on a 2 component phase diagram where both compounents freeze out at the same time?

2. What is the critical point in a three component phase diagram called?

3. What are the degrees of freedom in a system that contains CO2, H2O, and H2CO3 added independently, with only the liquid and gaseous phases present?

( Note: CO2 (g) + H2O (l) —> H2CO3 (aq) )

4. What is the mole fraction of water in the vapor over a solution of 2.00 moles of water and 2.00 moles of methanol at 50.0oC, if the vapor pressure of methanol and water at this temperature are 100.0 torr and 92.51 torr respectively?

Chapter 7

1. What is the chemical potential of H2O2(g) at 298.15 K and 10.00 atm if it is -105.57 kJ/mol at 1.00 atm?

2. What is the ΔG, ΔH, and ΔS of mixing 4.00 mol of N2 with 2.00 mol of O2 at 300.0 K if both gases are acting ideal?

3. What is the temperature at which an 0.100 molal aqueous solution of isopropanol(C3H8O) will boil? (ΔHVAP=44.0 kJ/mol)

4. What is the molar mass of a compound if its osmotic pressure at 298K is 34.0 torr when 0.2 grams is added to 0.500 liters?

Chapter 7a

1. What is the equilibrium constant for the following reaction at 298 and 400.0 K?

C2H5OH (g) → H2O(g) + C2H4 (g)

ΔHo298= -45.54 kJ/mol, ΔGo298= -8.068 kJ/mol

2. What is the ΔG for the reaction ( at 298K) in 1. if the partial pressures of C2H5OH, C2H4, and H2O are 1.00 bar, 0.100 bar and 0.100 bar respectively? What are the equilibrium partial pressures if the total pressure is 1.00 bar at 298 K?

3. What would be the effect of pressure on the equilibrium constant in 1. above?

4. What would the degree of dissociation be for the reaction are equilibrium in question 1. above at 1 bar and 298 K, 20 bar and 298 K

5. What are the degrees of freedom in a system that contains CO2, H2O, and H2CO3 added independently, with only the liquid and gaseous phases present?

( Note: CO2 (g) + H2O (l) → H2CO3 (aq) )

6. What is the pKa of an acid if the pH of a solution of the acid and its’ conjugate base at concentrations of 0.0500 m and 0.500 m, respectively is 5.00?

7. For the following electrochemical cell, what is the Eo, ΔGo, ΔHo, ΔSo and ΔCpo if the (dEo/dT) and (d2Eo/dT2) are 5.86 x 10-4 V/K and -4.74 x 10-6 V/K2 respectively at 298.15K?

Pt(s) | H2(g) | H+(aq) || Cl-(aq) | Cl2(g) | Pt(s)

8. What is the half reaction for the cathode in the following electrochemical cell? What kind of electrode is the cathode?

Pt(s) | H2(g) | H+(aq) || Cl-(aq) | Hg2Cl2(s) | Hg(s)

Chapter 8

1. What is the point called on a 2 component phase diagram where both compounents freeze out at the same time?

2. What is the critical point in a three component phase diagram called?

Chapter 8a

1. What is the pKa of an acid if the pH of a solution of the acid and its’ conjugate base at concentrations of 0.0500 m and 0.500 m, respectively is 5.00?

2. What is the fraction of free carbonate ion in a solution of 0.100M carbonic acid at 25oC if the pH of the solution is 10.000 and the pK2 amd pK1 of carbonic acid are 6.352 and 10.329 respectively?

3. At 25.0oC the molar conductance of dilute solution (0.0100 M) of acidic acid (CH3COOH), a weak acid, is 16.5 S cm2/mol. If the limiting molar conductance of acetic acid is 390.71 S cm2/mol, what is the Ka for acetic acid?

4. What is limiting molar conductance and the coefficient to Kohlrausch’s equation if the molar conductances of 0.0062 and 0.0150 M solutions are 109.9 and 106.1 S cm2 mol-1 respectively?

5. What is the specific conductivity and molar conductivity of a 0.100M KCl solution if the cell constant for the cell is 1.10 cm-1 and the resistance of the solution is 85.56 W?

Chapter 9

1. What is the equilibrium constant for the following reaction at 298 and 400.0 K?

C2H5OH (g) → H2O(g) + C2H4 (g)

ΔHo298= -45.54 kJ, ΔGo298= -8.068 kJ

2. What is the ΔG for the reaction ( at 298K) in 1. if the partial pressures of C2H5OH, C2H4, and H2O are 1.00 bar, 0.100 bar and 0.100 bar respectively? What are the equilibrium partial pressures if the total pressure is 1.00 bar at 298 K?

3. What would be the effect of pressure on the equilibrium constant in 1. above?

4. What would the degree of dissociation be for the reaction are equilibrium in question 1. above at 1 bar and 298 K, 20 bar and 298 K

5. What are the degrees of freedom in a system that contains CO2, H2O, and H2CO3 added independently, with only the liquid and gaseous phases present?

( Note: CO2 (g) + H2O (l) → H2CO3 (aq) )

6. What is the pKa of an acid if the pH of a solution of the acid and its’ conjugate base at concentrations of 0.0500 m and 0.500 m, respectively is 5.00?

Chapter 10

1. For the following electrochemical cell, what is the Eo, ΔGo, ΔHo, ΔSo and ΔCpo if the (dEo/dT) and (d2Eo/dT2) are 5.86 x 10-4 V/K and -4.74 x 10-6 V/K2 respectively at 298.15K?

Pt(s) | H2(g) | H+(aq) || Cl-(aq) | Cl2(g) | Pt(s)

2. What is the half reaction for the cathode in the following electrochemical cell? What kind of electrode is the cathode?

Pt(s) | H2(g) | H+(aq) || Cl-(aq) | Hg2Cl2(s) | Hg(s)

3. What is the mean activity coefficient of PbCO3 at an ionic strength of 0.1 m, if its solubility in pure water and 0.100 m KCl are 4.12 x 10-7 and 3.52 x 10-5 moles per Kg of water, respectively?

4. What is the solubility of AgBr in pure water based on the half reactions given in your book on page 1091?

5. What is the γ±of HCl if the E of a 0.100 molal solution is 0.3524 V? Use the half cell reactions from your book to determine the Eo.

Pt(s) | H2(g) | H+(aq) : Cl-(aq) | AgCl(s) | Ag(s)

6. What are the mean activity, mean activity coefficient, and mean molality of a 0.0200 molal solution of MgCl2 using the Debye Huckel Theory? Using the extended Debye Huckel Theory?

Chapter 17

1. What happens to the pressure of a gas when the speed of the gas molecules double?

2. What is the nRMS, most probale speed and mean speed for Ar at 300K?

3. A sample of H2 excapes through a pin hole in a container at a rate of 2.65 mmol/s. How long will it take Ar to effuse from the same container at the same temperature and pressure?

4. What is the collision frequency, collision density and mean free path of Ar at 300K and 1 bar if the diameter of argon is 0.300nm?

Chapter 18

1. The rate of the reaction A + 2B ® 3C + D was reported as 1.00 M/s. State the rates of formation and consumption of the reactants and products.

2. A reaction of 2A ® P follows second order rate law. If 30.0 minutes are required for the concentration A to change from 0.260 M to 0.110 M, what is the rate constant?

3. Carbon-14 is used to determine how long it has been since a plant died. This is done assuming the fraction of carbon as 14C of all living plants is the same. A sample of wood from a dead tree has 72.0% of the 14C of a living tree, how long has the tree been dead, if the half-life of 14C is 5730 years?

4. What is the rate constant for the first order conversion of cyclopropane to propene at 298 K, if the energy of activation and pre-exponential factor are 272 kJ/mol and 1.58 x 1015 s-1, respectively?

5. What is the Energy of Activation (Ea) and the pre-exponential factor(A) for the following 2nd order reaction if the rate constant at 307 and 273K are 2.71 x 10-9 and 1.43 x 10-9 M-1s-1?

C10H8- + C10H8 ® C10H8 + C10H8-

6. Given the following consecutive reactions

k1 k2

2A ® B + C ® D

and that the second reaction is the rate determining step, what must be true about the comparison of the concentration of A & k1 and the concentration of B, C & k2 ?

7. The reaction A ® 2 B , has a forward rate constant of 1.00 x 10-3 s-1 at 298 K. If the K for this reaction is 2.2 x 10-6 , what are the rate constant for the reverse reactions?

Chapter 19

1. What is the pre-exponential factor for a reaction A + B ® C at 400. K, if the collision diameter and reduced mass are 1.00 nm and 5.0 x 10-26kg ? (kB=1.38 x 10-23J/K)

2. The pre-exponential factor for the gas-phase decomposition of ozone at low pressures is 4.6 x 1012 s-1 and its activation energy is 10.0kJ mol-1. What are the entropy of activation, the enthalpy of activation and the gibbs free energy of activation at 298K

Chapter 20

1. What is the viscosity of a polymer solution in toluene if the viscosity of pure toluene is 0.590 x 10-4 kg poise and it takes the solution 10 times as long to drain as the pure toluene in the viscometer at the same temperature (20.0oC)? (rsolution=0.8787g/mL , rtoluene=0.8660g/mL)

2. A macromolecule has a diffusion coefficient of 4.0 x 10-11 m2s-1 in water at 20.0oC . A cylinder with pure solvent is placed on a second cylinder with a solution of macromolecule at a concentration of 0.0100 M. The macromolecule is allowed to diffuse into a second container of pure solvent for 3600 s. What is the mean square distance (standard deviation s ) the macromolecule will travel in this time?

3. A cylinder with pure solvent is placed on a second cylinder with an aqueous solution of macromolecule at a concentration of 0.0100 M. The macromolecule is allowed to diffuse into a second container of pure solvent for 3600 s. What is the diffusion coefficient if the solvent column is 20.0 cm tall and the final concentration in the solvent column is 8.00 x 10-5 M?

4. Given the following reaction and its expression for rate, what is the catalysis?

S + B <=> P, n = k[S][B][HA]

5. The A <=> B , equilibrium is disturbed by a shock but returns with a realtion time (t) of 100.0 ms at 298 K. If the K for this reaction is 3.3 x 10-6 , what are the rate constants for the forward and reverse reactions?

6. An enzyme having a Km of 3.9 x 10-5 M is studied at an initial substrate concentration of 0.035 M. After 1 min, it is found that 6.2 mmol L-1 of product has been produced. Calculate the turnover number (k2) and the amount of product formed at 4.5 min if the initial enzyme concentration is 1.00 x 10-6M.

7. A and B, are neutral species with equal radii and diffusion coefficients of 6.50 x 10-10 m and 2.50 x 10-10 m2 s-1, respectively. These molecules undergo a diffusion controlled reaction A + B ® P, at 40oC. Calculate the rate constant & initial rate of reaction if the concentration of A and B are 0.0150M and 0.0330M respectively.

Chapter 21

1. What is the viscosity of a polymer solution in toluene if the viscosity of pure toluene is 0.590 x 10-4 kg poise and it takes the solution 10 times as long to drain as the pure toluene in the viscometer at the same temperature (20.0oC)? (ρsolution=0.8787g/mL , ρtoluene=0.8660g/mL)

2. A macromolecule has a diffusion coefficient of 4.0 x 10-11 m2s-1 in water at 20.0oC . A cylinder with pure solvent is placed on a second cylinder with a solution of macromolecule at a concentration of 0.0100 M. The macromolecule is allowed to diffuse into a second container of pure solvent for 3600 s. What is the mean square distance (standard deviation s ) the macromolecule will travel in this time?

3. A cylinder with pure solvent is placed on a second cylinder with an aqueous solution of macromolecule at a concentration of 0.0100 M. The macromolecule is allowed to diffuse into a second container of pure solvent for 3600 s. What is the diffusion coefficient if the solvent column is 20.0 cm tall and the final concentration in the solvent column is 8.00 x 10-5 M?

4. What happens to the pressure of a gas when the speed of the gas molecules double?

5 . What is the ν RMS, most probale speed and mean speed for Ar at 300K?

6. A sample of H2 excapes through a pin hole in a container at a rate of 2.65 mmol/s. How long will it take Ar to effuse from the same container at the same temperature and pressure?

7. What is the collision frequency, and mean free path of Ar at 300K and 1 bar if the diameter of argon is 0.300nm?

8. At 25.0oC the molar conductance of dilute solution (0.0100 M) of acidic acid (CH3COOH), a weak acid, is 16.5 S cm2/mol. If the limiting molar conductance of acetic acid is 390.71 S cm2/mol, what is the Ka for acetic acid?

9. What is limiting molar conductance and the coefficient to Kohlrausch’s equation if the molar conductances of 0.0062 and 0.0150 M solutions are 109.9 and 106.1 S cm2 mol-1 respectively?

10. What is the specific conductivity and molar conductivity of a 0.100M KCl solution if the cell constant for the cell is 1.10 cm-1 and the resistance of the solution is 85.56 Ω?

Chapter 22

1. The rate of the reaction A + 2B → 3C + D was reported as 1.00 M/s. State the rates of formation and consumption of the reactants and products.

2. A reaction of 2A → P follows second order rate law. If 30.0 minutes are required for the concentration A to change from 0.260 M to 0.110 M, what is the rate constant?

3. Carbon-14 is used to determine how long it has been since a plant died. This is done assuming the fraction of carbon as 14C of all living plants is the same. A sample of wood from a dead tree has 72.0% of the 14C of a living tree, how long has the tree been dead, if the half-life of 14C is 5730 years?

4. What is the rate constant for the first order conversion of cyclopropane to propene at 298 K, if the energy of activation and pre-exponential factor are 272 kJ/mol and 1.58 x 1015 s-1, respectively?

5. What is the Energy of Activation (Ea) and the pre-exponential factor(A) for the following 2nd order reaction if the rate constant at 307 and 273K are 2.71 x 10-9 and 1.43 x 10-9 M-1s-1?

C10H8- + C10H8 → C10H8 + C10H8-

6. Given the following consecutive reactions

k1 k2

2A → B + C → D

and that the second reaction is the rate determining step, what must be true about the comparison of the concentration of A & k1 and the concentration of B, C & k2 ?

7. The reaction A → 2 B , has a forward rate constant of 1.00 x 10-3 s-1 at 298 K. If the K for this reaction is 2.2 x 10-6 , what are the rate constant for the reverse reactions?

8 . The A <=> B , equilibrium is disturbed by a shock but returns with a realtion time (t) of 100.0 ms at 298 K. If the K for this reaction is 3.3 x 10-6 , what are the rate constants for the forward and reverse reactions?

Chapter 23

1. Given the following reaction and its expression for rate, what is the catalysis?

S + B <=> P, ν = k[S][B][HA]

2 . Identify the following reactions in accordance with the step in a chain reaction that they represent for th efollowing reaction H2 + Br2 –> 2 HBr

R2 —> 2 R ·

Br · + H2 —> HBr + H ·

Br · + H · —> HBr

HBr + H · —> H2 + Br ·

3 . An enzyme having a Km of 3.9 x 10-5 M is studied at an initial substrate concentration of 0.035 M. After 1 min, it is found that 6.2 mmol L-1 of product has been produced. Calculate the turnover number (k2) and the amount of product formed at 4.5 min if the initial enzyme concentration is 1.00 x 10-6M.

4. The reactant 1,3-cyclohexadiene can be photochemically converted to cis-hexatriene. In an experiment, 2.5 mmo; of cyclohexadiene are converted to cis-hexatriene when irradiated with 100 W of 1.068 x 1015 Hz light for 27s. All of the light is absorbed by the sample. What is the overall quantum yield for this photochemical process?

Chapter 24

1. What is the pre-exponential factor for a reaction A + B → C at 400. K, if the collision diameter and reduced mass are 1.00 nm and 5.0 x 10-26kg ? (kB=1.38 x 10-23J/K)

2. In an aqueous solution at 25 Cand a pH of 7.4 the diffusion coefficient for hemoglobin is 7.6 x 10-7 cm2 s-1 (r = 3.5nm) and the diffusion coefficient for O2 is 2.2 x 10-5 cm2 s-1 (r = 0.20 nm). The rate constant for the binding of O to hemoglobin is 4 x 107 M -1s-1. Is this a diffusion controlled reaction?

Chapter 25

1. The rate of the reaction A + 2B → 3C + D was reported as 1.00 M/s. State the rates of formation and consumption of the reactants and products.

2. A reaction of 2A → P follows second order rate law. If 30.0 minutes are required for the concentration A to change from 0.260 M to 0.110 M, what is the rate constant?

3. Carbon-14 is used to determine how long it has been since a plant died. This is done assuming the fraction of carbon as 14C of all living plants is the same. A sample of wood from a dead tree has 72.0% of the 14C of a living tree, how long has the tree been dead, if the half-life of 14C is 5730 years?

4. What is the rate constant for the first order conversion of cyclopropane to propene at 298 K, if the energy of activation and pre-exponential factor are 272 kJ/mol and 1.58 x 1015 s-1, respectively?

5. What is the Energy of Activation (Ea) and the pre-exponential factor(A) for the following 2nd order reaction if the rate constant at 307 and 273K are 2.71 x 10-9 and 1.43 x 10-9 M-1s-1?

C10H8- + C10H8 → C10H8 + C10H8-

6. Given the following consecutive reactions

k1 k2

2A → B + C → D

and that the second reaction is the rate determining step, what must be true about the comparison of the concentration of A & k1 and the concentration of B, C & k2 ?

7. The reaction A → 2 B , has a forward rate constant of 1.00 x 10-3 s-1 at 298 K. If the K for this reaction is 2.2 x 10-6 , what are the rate constant for the reverse reactions?

Chapter 26

1. Given the following reaction and its expression for rate, what is the catalysis?

S + B <=> P, n = k[S][B][HA]

2 . The A <=> B , equilibrium is disturbed by a shock but returns with a realtion time (t) of 100.0 ms at 298 K. If the K for this reaction is 3.3 x 10-6 , what are the rate constants for the forward and reverse reactions?

3 . An enzyme having a Km of 3.9 x 10-5 M is studied at an initial substrate concentration of 0.035 M. After 1 min, it is found that 6.2 mmol L-1 of product has been produced. Calculate the turnover number (k2) and the amount of product formed at 4.5 min if the initial enzyme concentration is 1.00 x 10-6M.

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