November 26, 2024, 10:41:05 AM
Forum Rules: Read This Before Posting


Topic: Units for constant k in reaction rate laws.  (Read 3012 times)

0 Members and 1 Guest are viewing this topic.

Offline OTI

  • Regular Member
  • ***
  • Posts: 31
  • Mole Snacks: +0/-0
Units for constant k in reaction rate laws.
« on: February 21, 2016, 04:25:01 PM »
Basically, I want to know how you find out the units for the constant k in the reaction rate law thing.

This thing: RATE = k [A]m [ B]n

I know that for each order of reaction the units on k is different, but i don't know what they are.
It would really help if someone would explain them for me. Thanks.
« Last Edit: February 21, 2016, 04:53:57 PM by Borek »

Offline AdiDex

  • Full Member
  • ****
  • Posts: 305
  • Mole Snacks: +16/-12
  • Gender: Male
Re: Units for constant k in reaction rate laws.
« Reply #1 on: February 22, 2016, 02:29:21 AM »
Go and learn The Principle of Homogeneity of Dimensions .

It's a quite basic concept . You should know it . You can find in any High School Physics Book in starting . How do we find dimensions and units etc.

Offline Burner

  • Full Member
  • ****
  • Posts: 198
  • Mole Snacks: +15/-2
  • Gender: Male
  • Chem-is-try
Re: Units for constant k in reaction rate laws.
« Reply #2 on: February 22, 2016, 05:48:15 AM »
Unit of rate is mol dm-3 s-1
Unit of concentration(e.g. [A], [ B]) is mol dm-3
How do you use these units to derive the unit of rate constant k?
Year 1 science student in HKUST and a Chemistry geek.
If I make any mistakes in the forum, please don't hesitate to correct me as I want to learn.

Offline OTI

  • Regular Member
  • ***
  • Posts: 31
  • Mole Snacks: +0/-0
Re: Units for constant k in reaction rate laws.
« Reply #3 on: February 25, 2016, 09:08:18 PM »
Oh, I get it now! I supposed to balance the right side's units so it matches the rate's units right?

Wow. That was simple.

Offline Burner

  • Full Member
  • ****
  • Posts: 198
  • Mole Snacks: +15/-2
  • Gender: Male
  • Chem-is-try
Re: Units for constant k in reaction rate laws.
« Reply #4 on: February 25, 2016, 09:21:35 PM »
Yes
Year 1 science student in HKUST and a Chemistry geek.
If I make any mistakes in the forum, please don't hesitate to correct me as I want to learn.

Offline Vidya

  • Full Member
  • ****
  • Posts: 839
  • Mole Snacks: +46/-62
  • Gender: Female
  • Online Chemistry and Organic Chemistry tutor
    • Online Chemistry Tutor
Re: Units for constant k in reaction rate laws.
« Reply #5 on: February 27, 2016, 10:57:02 AM »
Basically, I want to know how you find out the units for the constant k in the reaction rate law thing.

This thing: RATE = k [A]m [ B]n

I know that for each order of reaction the units on k is different, but i don't know what they are.
It would really help if someone would explain them for me. Thanks.
Plug in the units of Rate and conc A and B with exponential coefficients m and n respectively.Do mathematics  to know units of k

Sponsored Links