January 16, 2025, 08:45:49 AM
Forum Rules: Read This Before Posting


« previous next »
Pages: [1]   Go Down

Topic: Half life/ instantaneous rate problem  (Read 3602 times)

0 Members and 1 Guest are viewing this topic.

Offline Korokian

  • Regular Member
  • ***
  • Posts: 90
  • Mole Snacks: +3/-2
Half life/ instantaneous rate problem
« on: March 06, 2007, 06:10:53 PM »
The half-life of a first order reaction is 140s.  What is the instantaneous rate of the reaction when the reactant concentration is 0.19M?

I am clueless on how to start this.... help would be appreciated.
Logged

Offline Yggdrasil

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 3215
  • Mole Snacks: +485/-21
  • Gender: Male
  • Physical Biochemist
Re: Half life/ instantaneous rate problem
« Reply #1 on: March 07, 2007, 01:12:25 AM »
Can you write an expression for the concentration of your reactant as a function of time?
Logged

Offline Korokian

  • Regular Member
  • ***
  • Posts: 90
  • Mole Snacks: +3/-2
Re: Half life/ instantaneous rate problem
« Reply #2 on: March 07, 2007, 03:45:55 PM »
i don't know how to write the function but what i do know is the initial concentration is halved after 140 seconds

i figured out k in t1/2=ln2/k

140s=ln2/k
k=.00495

and rate=k[A]

rate=.00495 x .19
rate= 9.41 x 10-4?
« Last Edit: March 07, 2007, 04:02:58 PM by Korokian »
Logged

Offline Yggdrasil

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 3215
  • Mole Snacks: +485/-21
  • Gender: Male
  • Physical Biochemist
Re: Half life/ instantaneous rate problem
« Reply #3 on: March 07, 2007, 04:33:43 PM »
Looks right to me.  Good job.
Logged

Offline Korokian

  • Regular Member
  • ***
  • Posts: 90
  • Mole Snacks: +3/-2
Re: Half life/ instantaneous rate problem
« Reply #4 on: March 07, 2007, 05:22:39 PM »
Thank You!
Logged
Pages: [1]   Go Up
« previous next »
Sponsored Links