# Math Help - science question!

1. ## science question!

a) The activation energy needed to convert cis-retinal to trans-retinal is 4 × 10–19 J. What is the reaction rate for one molecule at body temperature (310 K)? In the absence of light, how long would you have to wait for a reaction to take place?

b) What wavelength of light is required to convert cis-retinal to trans-retinal? If the molecule were exposed to a blackbody at 310 K, should we expect a lot of photons with this wavelength?

Any idea how to start these?

Thanks

2. I guess that you know about the Arrhenius equation which I just came to know using google... which is:

$k = Ae^{-E_a/RT}$

But apart from the first part in part (b), I don't know how to tackle the problem.

For (b) use $E = \dfrac{hc}{\lambda}$

$E = 4\times 10^{-19} J$

$h = 6.63 \times 10 ^{-34}Js$

$c = 3.0\times 10^8 ms^{-1}$

Lambda is what you are looking for.