Change in temperature/ rate

I recently did an experiment where I changed teh temperature from 24°C to 40°C then to 70°C.
The rate increased, as expected, but...

The difference in rate when i changed the temperature from 24°C to 40°C was much bigger than the change of rate between 40°C and 70°C, despite the temperature gap being smaller.

Is there any explanation fo this? Or is it anomalous?
Ta!

At 24°C the reaction took 200seconds
At 40°C the reaction took 140seconds
At 70°C the reaction took 120seconds

Reply 1

Chaoslord

16

bigger difference?

cause the rate was larger maybe? o.O

(elaborate please)

Reply 2

Kashya

13

That's extremely vague.

What was the experiment?

Reply 3

IChem

11

Reaction is exothermic, increased temperature leads to increased rate, temperature increases faster, rate increases.....etc.

Edit: Ahhh, misunderstood OPs question!

Reply 4

Reba1

OP

It was pottassium mangante and ethanedioic acid.
The thing that confused me:

At 24°C the reaction took 200seconds
At 40°C the reaction took 140seconds

So an increase of 16°C reduced the reaction by 1 minute

At 70°C the reaction took 120seconds

Here an increase of 30°C only reduced the reaction by 20 seconds
??

Surely a bigger rise in temperature would mean a bigger loss in time?

Reply 5

IChem

11

Halfth order reaction wrt temperature?

Reply 6

Creative

10

Isn't that reaction autocatalytic..both the Mn2+ ions produced in the reaction as well as the temperature increase the rate of reaction?

Reply 7

IChem

11

I think it is, which makes the OPs times somewhat....dubious

Reply 8

Chaoslord

16

isnt it simply cause its not a linear relationship between temperature and rate of reaction?

Reply 9

Robob

17

Reba1

It was pottassium mangante and ethanedioic acid.
The thing that confused me:

At 24°C the reaction took 200seconds
At 40°C the reaction took 140seconds

So an increase of 16°C reduced the reaction by 1 minute

At 70°C the reaction took 120seconds

Here an increase of 30°C only reduced the reaction by 20 seconds
??

Surely a bigger rise in temperature would mean a bigger loss in time?

According to you, if I carry the reaction out at a high enough temperature, it will take a negative amount of time.

Reply 10

DomAD

9

Chaoslord

isnt it simply cause its not a linear relationship between temperature and rate of reaction?

That's what I thought. Maybe the temperature vs. reaction rate graph is shaped like -x^2.

Reply 11

Chaoslord

16

DomAD

That's what I thought. Maybe the temperature vs. reaction rate graph is shaped like -x^2.

minus x^2? lol higher temps mean NO reaction =P

i reckon its a curve with a limit

kinda like root x graph but tending to a limit (y = something)

but i dont think op cares anymore ^_^

Reply 12

DomAD

9

Chaoslord

minus x^2? lol higher temps mean NO reaction =P

i reckon its a curve with a limit

kinda like root x graph but tending to a limit (y = something)

but i dont think op cares anymore ^_^

Haha, forgot about that. Basically i think we've established that the relationship between temperature and rate of reaction is not linear.