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Rate Law A dimer is a molecule composed of two identical molecules. Butadiene (C

ID: 984892 • Letter: R

Question

Rate Law

A dimer is a molecule composed of two identical molecules. Butadiene (C4H6) reacts to form its dimer according to 5. the equation: 2CAH (g) 8 (g) The following data were collected for this reaction at a given temperature: [C4H6] (M) Time (s) 0.01000 0.00625 1000 0.00476 1800 0.00370 2800 0.00313 3600 0.00270 4400 0.00241 5200 0.00208 6200 a) ls this reaction zero, first or second-order? (HINT: do a graphical analysis) b) What is the value of the rate constant for the reaction? c) What is the half-life for the reaction under the conditions of this experiment?

Explanation / Answer

a) to determine the order of reaction we will first plot a graph between concentration and time

If it is straght line then it must be zero order reaction .

If it is a curver then we wil draw a graph between ln of concentration and time

If it is straight line then it must be first order

If it s curve then we will draw a grpah between 1/ [Concentration ] and time

If it is a straight line then it must be second order

so let us check

It is a curve

b) first order anaylsis

Almost a straight line, so this is first order reaction

b) the rate constant = - Slope

the rate equation is

kt = ln [A0/lnAt]

kt = lnA0 - lnAt

lnAt = lnA0 - kt

the equation for graph is

y = -0.0002x - 4.8066

slope = -k = 0.0002

c) half life = 0.693 / K = 0.693 / 0.0002 = 3465 sec-1

cocnentration time 0.01 0 0.00625 1000 0.00476 1800 0.0037 2800 0.00313 3600 0.0027 4400 0.00241 5200 0.00208 6200