# college: Chemistry

posted by .

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.

• college: Chemistry -

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.

• college: Chemistry -

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.

• college: Chemistry -

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.