Possibly Useful Physical Constants and Conversion Factors

Possibly Useful Equations
       
     
 
The Arhenius equation:        
Unimolec. gaseous or aqueous reaction;    
           
     
Bimolec. gas phase reaction ;
             
       
           
     
     
For a bubble:
For a droplet:
For                
     





1.
For an electrolyte the variation of the molar conductivity () with , where is the electrolyte molarity and , followed the relation,
Which of the following choices for the nature of the electrolyte and its molar conductivity at infinite dilution () is correct?
Electrolyte              
A.
strong          
B.
strong          
C.
weak            
D.
weak            
E.
strong            


2.
The solubility product of BaSO4 is . Assuming that the Debye-Huckel limiting law (DHLL) is obeyed find the solubility of BaSO4 in a 0.05 M KCl solution.
A.
B.
C.
D.
E.


3.
Which of the following would have the same ionic strength as a 1.0 M aqueous solution of Cs2SO4?
A.
3.00 M RbCl
B.
0.350 M K3PO4
C.
0.175 M Ti2(SO4)3
D.
0.125 M Ni(NO3)2
E.
0.01 M CuSO4


4.
Determine the voltage for the following cell
Zn (s), Hg ()| ZnCl2 ( 0.01m ) | AgCl (s) | Ag (s)
at 25.0 0C given E0 = 0.253 V and ZnCl2 (aq, 0.01m) has a mean activity coefficient of 0.112.
A.
0.495   V
B.
0.358   V
C.
0.267   V
D.
0.326   V
E.
0.891   V


5.
Determine the solubility product for AgI at 25.0 °C, given the following half- cells:

      AgI (s)   + e¯     Ag (s) + I- (aq)         E0 = - 0.15V
      Ag+ (aq) + e¯         Ag(s)                    E0 =   0.80V
A.
8.57 x 10-17
B.
9.73 x 10-17
C.
6.71 x 10-17
D.
2.31 x 10-17
E.
1.14 x 10-17


6.
The cell
Pt, H2 (1 bar)|H+ (1 m)||Fe3+, Fe2+|Pt      Eo = 0.771 V

has an EMF of 1.45 V at 25 oC. The [Fe3+] / [Fe2+] ratio is:
A.
3.05 x 10 11
B.
2.94 x 10 - 38
C.
3.40 x 10 - 37
D.
1.98 x 10 11
E.
1.12 x 10 - 23


7.
Given Eo = - 0.356 V and E = - 0.256 V for the following cell at 25oC:

Pt, H2 (1 bar)| H2SO4 (aq, a = ?) | PbSO4 (s) | Pb (s)        

calculate the mean activity of H2SO4.
A.
B.
C.
D.
E.
       


8.
The standard potential of the Cl | AgCl(s) |Ag(s) electrode over a range of temperatures has been found to fit the expression,
Eo /V = 0.23659 – 4.8564x 10- 4 T
calculate the entropy of the formation of Cl at 298 K.
A.
- 46.86 J K-1 mol-1
B.
+ 46.84 J K-1 mol-1
C.
+ 48.21 J K-1 mol-1
D.
- 48.21 J K-1 mol-1
E.
+ 21.11 J K-1 mol-1


9.
The thermal decomposition of acetone, (CH3)2CO, at 600 oC proceeds through the formation of the intermediate ketene CH2CO


If and determine the time in seconds at which the ketene intermediate reaches its maximum concentration.
A.
107
B.
20
C.
46
D.
10
E.
75


10.
The rate constant for the second-order reaction,
A → Products
is 0.13 M-1s-1. In how many seconds would the concentration of A drop from 0.26 mol L-1 to 0.13 mol/L?
A.
30
B.
4.4 x 10-3
C.
0.017
D.
0.50
E.
1.0


11.
The concentration gradient of ferrocene molecules in solution in aqueous ethanol, in an electrochemical cell at 25 oC, is . Calculate the value of the flux of ferrocene molecules towards the electrode given that the diffusion coefficient of ferrocene in dilute aqueous ethanol solution is .
A.
B.
C.
D.
E.


12.
If for the following reaction:
3A → 2B,
The rate of appearance of B, , is related to the rate of disappearance of A is given by,
Then the factor is:
A.
- 2/3
B.
+1/2
C.
- 3/2
D.
+1
E.
- 1/3


13.
The half-lives for a first order reaction in solution are 2.00 hours at 25.0 oC and 1.00 hours at 35.0 oC. The activation enthalpy of the reaction at 35.0 oC is:
A.
50.3 kJ mol-1
B.
52.9 kJ mol-1
C.
23.1 kJ mol-1
D.
76.1 kJ mol-1
E.
29.1 kJ mol-1


14.
For the reaction,
2N2O5 → 4 NO2 + O2
The following mechanism was proposed

 
N2O5
 
NO2 + NO3           (Fast Equilibrium;   K =k1/k-1)
               NO2 + NO3       NO + O2 + NO2      (slow step)
               NO + NO3     2NO2               (fast)

The rate law predicted by this mechanism is:
A.
B.
C.
D.
E.


15.
The quantum yield for the photolysis of HI (g) to H2 (g) + I2 (g) by light of wavelength 253.7 nm is 1.00. Calculate the amount of HI that will be decomposed if 300 J of light at this wavelength is absorbed.
A.
0.636 mmol
B.
0.123 mmol
C.
6.29   mmol
D.
1.22   mol
E.
11.6   mol


16.
For the reaction:
A (g) → B (g)   +   C (g)
the following data are obtained:

        Time / hours           0                 6
        Ptotal / kPa            11.07          17.26  

Calculate the rate constant given that
[Hint: ]
A.
3.79 x 10-5 s -1
B.
1.24 x 10-2 s -1
C.
2.21 x 10-3 s -1
D.
4.11 x 10-4 s -1
E.
3.21 x 10-7 s -1


17.
The viscosity of blood at the body temperature of 310 K is 3.95 cP. If blood flow through a vein 2.20 cm in length and 1.40 mm in radius results in a pressure drop of 45.0 torr, the rate of flow of the blood is:
A.
B.
C.
D.
E.


18.
The sedimentation coefficient of cytochrome in water at 22 oC was determined by centrifuging at 40,000 revolutions per minute (rpm). The locations of the boundary were measured at and at different times . A plot of versus was linear with a slope of . The sedimentation coefficient, , of cytochrome is:
A.
B.
C.
D.
E.


19.
The collisional cross section of a molecule 0.20 nm in radius is:
A.
0.50 nm2
B.
1.26 nm2
C.
2.51 nm2
D.
0.40 nm2
E.
0.63 nm2


20.
On average the distance travelled in 1000 s in one dimension by a particle with a diffusion coefficient of is close to:
A.
0.23 m
B.
0.16 m
C.
0.39 m
D.
26     m
E.
0.51 m


21.
The atomic mass of Krypton gas is and a Krypton molecule has a collisional cross section of . Calculate the diffusion coefficient for Krypton at 30 oC and 1.5 atm.
A.
B.
C.
D.
E.


22.
Which of the following statements on the thermal conductivity for a gas is FALSE?
A.
At moderate temperaturesis independent of temperature.
B.
generally increases as the temperature increases.
C.
At high temperatures experimental values are higher than theoretical hard sphere model values.
D.
At moderate pressures is independent of pressure.
E.
At high pressures increases sharply as pressure increases because of increase in molecular interactions.


23.
The diffusion coefficient of collagen in water at 20 oC was found to be . Calculate the effective radius of the collagen molecule given that the viscosity of water at 20 oC is .
A.
52     nm
B.
24     nm
C.
0.017 nm
D.
40     nm
E.
17     nm


24.
The pressure inside a soap bubble 50.0 mm in diameter is three times an external pressure of 1.00 atm. Calculate the surface tension in the soap film.
A.
B.
C.
D.
E.


25.
At 298 K a standard solution of KCl with resulted in a resistance of . At the same temperature and using the same conductivity cell an HCl solution resulted in a resistance of . The conductivity of the HCl solution is:
A.
B.
C.
D.
E.


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