How should i read chemistry ?

It takes 945.kj/mol to break a nitrogen-nitrogen triple bond. calculate the maximum wavelength of light for which a nitrogen-nitrogen triple bond could be broken by absorbing a single photon.

Which of the following is true for the actual yield of a reaction? it is always calculated as a ratio. it is the yield from the excess reactant. it is the yield from the limiting reactant. it is always less than the theoretical yield.

What is a difference between a mixture of elements and a mixture of compounds