It takes 348 to break a carbon-carbon single bond. calculate the maximum wavelength of light for which a carbon-carbon single bond could be broken by absorbing a single photon. round your answer to significant digits.

As given it takes 348 kJ of energy to break one mole of C-C bond

So energy required to break one C-C bond will be = 348 X 1000 / 6.023 X 10^23

Energy required = 5.78 X 10^-19 Joules

The relation between energy and wavelength is

E = hc / λ

where λ = wavelength

h = planck's constant

c= speed of light

5.78 X 10^-19 Joules = 6.62 X 10^-34 X 3 X 10^8 / λ

λ = 3.44 X 10^-7 m = the maximum wavelength of light for which a carbon-carbon single bond could be broken by absorbing a single photon

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)