I need these answered with step by step solutions so I can teach myself to do themConsider the...

Question

I need these answered with step by step solutions so I can teach myself to do them
Consider the following mechanism
step 1: AB + C —> A+ BC step 2: AB + BC --> AB2 + C
overall: 2AB --> A+ AB1
Which species is an intermediate?
r A .Q BC O AB • C o AB2
Which species is a catalyst?
The rate constant for this first-order reaction is 0250 s at 400 C. A products How long (in seconds) would it take for the concentration of A to decrease from 0.920 M to 0.330 M?
Number
The half-lives of different medical radioisotopes are given in the table below.. If the initial amount of phosphorus-32 is 2.0 mCi, how much phosphorus-32 is left in the body after 42 days?
Radioisotope : Half-life (days) arsenic-74 18 iodine-131 8 phosphorus-32 14 chromium-51 28
Number
mCi

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Robert · Accepted Answer

SolutionTTs070913_111312_1
1. BC is the intermediate because it is produced in one step and consumed in another step. It 
does not appear in the overall reaction. 
      C is catalyst because it has the characteristic of catalyst. It is added in step 1 and 
regenerated in step 2 i.e. it is neither consumed in the reaction nor transformed to another 
species.
2. Given,  
Rate constant = 0.250 s
-1
 
Initial concentration = 0.920M 
Final concentration = 0.330M 
We know, equation for the first order reaction, t  = (1/k) ln ([A0]/[A])
Putting the values in the equation for the first order reaction, we have 
t  = (1/k) log (0.920/0.330) 
Solving, t = 0.004 s
3. Decay of radioactive elements follow first order kinetics. 
Disintegration constant or Decay constant ( λ ) of a radioactive element is related to its 
half life (t1/2)  as: 
 λ =  0.693/ t1/2 
Therefore, λ (Phosphorus-32) =  0.693/ 14 = 0.4095
We know, λ = (1/t) ln ([N0]/[N])       N0 = Initial number of atoms 
                                                             N = Number of atoms after time t 
Inserting the values in the above equation, we have 
0.4095 = (1/42) ln ( 2.0/N) 
 N = 0.250 mCi.
4. If there is a change in molar concentration of reactant A,  ∆A = [A]final – [A]initial during 
time interval ∆t, then 
Average rate of reaction = - ∆A/∆t
Interval : 0 sec to 205 sec 
∆A = (1.76 -2.00) = -0.24 
∆t =  (205-0)s = 205s 
 Average rate of reaction = - (-0.24)/ 205 = 0.00117 M/s
Interval : 205 sec to 496 sec 
∆A = (1.46-1.76) = -0.30 
∆t =  (496-205) s = 291 s 
 Average rate of reaction = - (-0.30)/ 291 = 0.00103 M/s
Interval : 496 sec to 825  sec 
∆A = (1.19-1.46) = -0.

I need these answered with step by step solutions so I can teach myself to do them Consider the following mechanism step 1: AB + C —> A+ BC step 2: AB + BC --> AB2 + C overall: 2AB --> A+ AB1 Which...

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