college: Chemistry
posted by Shylo .
Hi can someone help me with this other problem from my homework,
The thermochemical equation is
C6H12O6(s)+ 6O2(g)> 6CO2(g)+ 6H2O(g)
reaction is 2539.01 kJ/mol
Part B) What is the minimum number of photons with wavelength of 645nm needed to prepare 135 grams of glucose?
Please give me some good information so, I will know how to do it on my own.

1) calculate the energy in a photon in 645 nm (Planck's equation).
2) determine the moles in 135g glucose.
3) determine the energy required: molesglucose*Reactionenergy/mole
4) divide the energy required by the energy in one photon. 
Work out the energy associated with each photon of wavelength 645 nm using
E=hf (you will need to convert 645 nm to a frequency first)
Calculate the molecular mass of glucose
Calculate the number of moles of glucose in 135 g
Multiply 2539.01 kJ/mol by the number of moles to get the kJ required.
divide the energy required by the energy of each photon to get the minimum number of photons. 
Don't you go back and read your posts? I solved this problem for you the first time you posted. This is a duplicate post and you took the time of THREE volunteers to answer the same one question.