So, I am working on my chemistry post-lab report and I'm having some difficulty with the math portion. Here is a quick run down of the experiment. We performed 2 experiments, (Reaction 1 and Reaction 2).
Rxn 1: Mix 1mL dye, D.I. water and NaOCl into vile & measure absorption/time
Rxn 2: Mix 1mL dye, 1.5 mL D.I. water and .5 mL NaOCl into vile & measure abs/time
a) The amount of each reactant used and how you carried out each reaction.
(This I've already completed... pretty self explanatory)
b) The plots of 0th, 1st and 2d order reaction from each reaction.
(For this, I created one table for each reaction with values for t, A, lnA and 1/A derived from the data abs/time collected from the experiment. But, I'm not sure how to plot this)
Reaction 1 Reaction 2
t A lnA 1/A t A lnA 1/A
0 1.9098 0.6469 0.5246 0 1.6341 0.4910 0.6119
298.9 0.3271 -1.117 3.057 298.9 0.6461 -0.4368 1.5477
499.0 0.1260 -2.071 7.936 499.0 0.3703 -0.9934 2.7005
699.2 0.0591 -2.8285 16.920 699.2 0.2342 -1.4515 4.2698
c) The calculation of reaction orders with respect to bleach and dye.
(For this I assumed I would use the following equations:
x=0 [dye]=[dye]_0-k_obs(t)
x=1 ln[dye]=ln[dye]_0-k_obs(t)
x=2 (1/[dye])=(1/[dye]_0)+k_obs(t)
and that I would use the concentration of the dye for the value of dye and solve for k_obs. So, for example, in x=0 .3271=1.9098-k_obs(298.9) which gives me a k_obs value of -0.005295 and k_obs is m or the slope of the line.
Then, I would use
Rate=k_obs^1[dye]^x where k_obs^1=k[NaOCl]_1^y
Rate=k_obs^2[dye]^x where k_obs^2=k[NaOCl]_2^y
If we divide these two equations for k_obs^1 and k_obs^2 y can be algebraically determined:
y=(log(k^1_obs/k^2_obs))/(log(NaOCl_1/NaOCl_2))
where k_obs^1=k[NaOCl]_1^y
NaOCl = 1.0
where k_obs^2=k[NaOCl]_2^y
NaOCl = 0.5
and (log(NaOCl_1/NaOCl_2) is
(log[M_1*V_1=M_2*M_2]_1/[M_1*V_1=M_2*M_2]_2)
=(log((.24)(1mL)=M_2(3mL)/(.24)(.5mL)=M_2(3mL))
=(log(0.08/0.04))=0.30103
But how would I solve the top? Would it be:
(log(k(1)_1^y/k(.5)_2^y)) where k is the rate constant determined by (delta(concentration))/(delta(time))
which k would be
rxn 1: 1.90980164-0.05913865/0-699.22365=-0.002647=k
rxn 2: 1.63419018-0.23425606/0-699.22365=-0.002002=k
Or would I use a k derived from one of the orders? Also, how do I determine which order each reaction is? I hypothesized that Reaction 1 is 0th order and Reaction 2 is 1st order.
d) The determination of rate constant, k.
For this I assumed I would use the following equations
x=0 [A]=[A]_0-k_obs(t)
x=1 ln[A]=ln[A]_0-k_obs(t)
x=2 (1/[A])=(1/[A]_0)+k_obs(t)
But, isn't this the same as the one for the dye? Or would the dye be the concentration of the dye itself and this is the absorption of each equation?
Please help! I've been working on this for 2 days and this is the only part I'm stuck on. Thanks!
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