What is the relationship between temperature and reaction rate?

[i_love_science]

Homework Statement

In general, if the temperature of a reaction is raised from 300 K to 320 K, the reaction rate will increase by a factor of approximately
A) 320 K/300 K
B) 22°C/2°C
C) 4
D) 2

Relevant Equations

Arrhenius equation

I think I should use ln(K2/K1)=Ea/R(1/T1 - 1/T2), and find K2/K1. I am given T1 and T2, but not Ea. I'm not sure how to continue.
Thanks.

(note: the answer is C)

 

[Borek]

That's only a rule of thumb, but for many reactions Ea is such that increasing temperature by 10 deg increases the rate about twice.