# chem kinetics help urgent!!

The rate constant, k, for a reaction varies with temperature as shown by the equation
k = Ae–EaIRT
For this reaction, at 25 °C, k = 3.46 × 10−8 s−1
The activation energy Ea = 96.2 kJ mol−1
The gas constant R = 8.31 J K−1 mol−1
Calculate a value for the Arrhenius constant, A, for this reaction.
Give the units for A

can someone show the working out for this question pls?
Original post by idk__21
The rate constant, k, for a reaction varies with temperature as shown by the equation
k = Ae–EaIRT
For this reaction, at 25 °C, k = 3.46 × 10−8 s−1
The activation energy Ea = 96.2 kJ mol−1
The gas constant R = 8.31 J K−1 mol−1
Calculate a value for the Arrhenius constant, A, for this reaction.
Give the units for A

can someone show the working out for this question pls?

Take the natural log of both sides (which spec. do you do? Both forms of the equation are on our datasheet), this will allow you to rearrange the equation to make A the subject.

Units wise: looking at the version of the equation you have, e to the power of anything is unitless, hence k = A x unitless. Go figure.
Ea value should be changed to J (x1000)Then take e^-Ea/RT (T inK =298)So units cancel out and A = 2.57x10^9 s^-1
Original post by Pigster
Take the natural log of both sides (which spec. do you do? Both forms of the equation are on our datasheet), this will allow you to rearrange the equation to make A the subject.

Units wise: looking at the version of the equation you have, e to the power of anything is unitless, hence k = A x unitless. Go figure.

hi i know it's been a year but i'm also doing this question as well. I've gotten a value for lnA, how would I convert that into A?
Original post by doka13
hi i know it's been a year but i'm also doing this question as well. I've gotten a value for lnA, how would I convert that into A?

no clue sorry lmao
Original post by doka13
hi i know it's been a year but i'm also doing this question as well. I've gotten a value for lnA, how would I convert that into A?

A = e^(lnA)
Original post by Pigster
A = e^(lnA)

hey guys I got the answer
but the mark scheme says that the question had a typographical error?
does anyone know what it was?
Original post by Lebkuchen
hey guys I got the answer
but the mark scheme says that the question had a typographical error?
does anyone know what it was?

nvm lol it was a misprint of the quotient and they got awarded full marks lucky them!