# Calculating Ea through slope

1. Feb 13, 2005

### relativitydude

For some reason, this isnt working out.

The Arhennius equation, k = A*e^(-Ea/RT)

I have tables of temperature and k. The book says just calculate it by having the x axis be 1/T and y axis be ln(k)

Ok, take Ln of both sides
ln(k) = ln(A*e^(-Ea/RT))
ln(k) = -Ea/RT + ln(A)

Oh, that looks like y = mx + b

2. Feb 13, 2005

### dextercioby

So there's actually no problem.It's a standard way of linearizing exponential laws...

Daniel.

3. Feb 13, 2005

### relativitydude

Ya, I was just being stupid.

4. Feb 13, 2005

### Gokul43201

Staff Emeritus
Note that Ea will be the absolute value of the slope. The slope will be negative, Ea must be positive.

5. Feb 13, 2005

### dextercioby

Gokul,if you wanted to be strict,u should have mentioned that Ea is the absolute value of the slope TIMES THE GAS CONSTANT "R"...

Daniel.

6. Feb 13, 2005

### Gokul43201

Staff Emeritus
I should have.

It's common to make the x-axis 1/RT or $\beta$ (when dealing with numbers instead of moles).