• Support PF! Buy your school textbooks, materials and every day products Here!

I need some freakin help with this half-life problem

  • #1
The uncoiling of DNA is a first order process with an activation energy of 430 kJ/mole. At 60oC, the half-life is estimated to be 2 minutes.
a. Write a chemical equation that represents this reaction. Then, write the rate law for this reaction.
b. Calculate the half-life at normal body temperature, 37 oC.
c. What is the chemical force that holds the DNA in its coiled state? Is the uncoiling of DNA favored by enthalpy or entropy or both? Give reasons.
d. Is the uncoiling of DNA spontaneous at 37 oC? Give reasons.
e. Draw a reaction energy diagram for the uncoiling of DNA.

here are some simple directions, b is the probelm im doing,
i got some formulas but i dont know which one ill use, im just confused with this, may u give me a hint or some information so i can figure this problem out, ill work and the problem and post it up in a bit
 

Answers and Replies

  • #2
what equation shall i use, .693/k or 1/k[A] with a little o at the bottom right
 
  • #3
ok i am suuppost to use the .693/k since this reaction is a first order reaction
 
  • #4
here's what i figured out, k = A e-Ea/RT

so i took the half life equation .693/k and changed it to .693/Ae -Ea/RT
 
  • #5
i plugged in my numbers which were .693/ Ae -430kj/mole / (8.1314 J / mole. K) ( 310 K)

i think im doing it right but how do i figure out Ae
 
  • #6
or what is Ae
 
  • #7
ok what is A because e is apart of the -Ea/RT
 

Related Threads on I need some freakin help with this half-life problem

  • Last Post
Replies
6
Views
3K
Replies
3
Views
10K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
2
Views
17K
  • Last Post
Replies
3
Views
2K
  • Last Post
Replies
12
Views
3K
  • Last Post
Replies
15
Views
9K
Replies
1
Views
18K
  • Last Post
Replies
6
Views
12K
Replies
5
Views
2K
Top