I am having trouble incorporating the 1 kg of Carbon to the percent weight of CO2 in the atmosphere. I know that the percent weight formula for CO2 is 0.046 = [mass of CO2/Total mass in atmosphere(Nitrogen + oxygen + dioxide)] X 100, but that does not relate to the weight of Carbon at all.

I know that I will have to use the ideal gas law and the unknown will be "n". I'm assuming that "n" is the moles of Carbon and that to get that, I have to somehow use the weight percent of Carbon Dioxide(0.046%) and through stoichiometry, convert it to the moles of carbon. The problem is that I do not know how to go from the weight percent to moles of carbon.