# Homework Help: First-Order Kinetics and Activation energy

1. Nov 12, 2009

### amcelroy13

1. The problem statement, all variables and given/known data
I already have an answer I'm just not sure if it's correct. This is done mostly graphically I just need to known if anyone else thinks it makes sense.

Given this data: what is the rate constant, K, for each reaction, half life of each reaction and activation of the reaction?

Time, Rxn@45C, @ 35C, @25C
0, 7.14E-5, 7.46E-5, 7.46E-5
5, 4.11E-5, 6.63E-5, 7.33E-5
10, 2.35E-5, 5.94E-5, 7.25E-5
15, 1.34E-5, 5.21E-5, 7.16E-5
20, 7.66E-6, 4.62E-5, 6.94E-5
25, 4.63E-6, 4.04E-5, 6.80E-5
30, 3.11E-6, 3.56E-5, 6.67E-5
25, 2.36E-6, 3.12E-5, 6.50E-5
40, 2.03E-6, 2.76E-5, 6.37E-5
45, 0 , 2.38E-5, 6.28E-5
50, “ “, 2.10E-5, 6.13E-5
55, “ “, 1.83E-5, 5.96E-5
60, “ “, 1.62E-5, 5.81E-5

K for reaction, 2.68mol-1, .570mol-1, .0675mol-1
Half-Life of Reaction, .259, 1.22, 10.3
Activation Energy of Reaction 145kJ/mol

I also don't know if half-life is supposed to be in minutes or hours or what?

2. Relevant equations

HL = ln(2)/K
ln(k) = -Ea/RT + ln(a)

3. The attempt at a solution