The world burns 4000 million tons (oil equivalent) of coal per year. Assuming that oil equivalent coal is 78% carbon by mass, how many moles of CO2 are emitted to the atmosphere each year from burning...

The world burns 4000 million tons (oil equivalent) of coal per year. Assuming that oil equivalent coal is 78% carbon by mass, how many moles of CO2 are emitted to the atmosphere each year from burning coal? 6.9 Natural uranium consists of 0.7% of fissile 235U isotope, with the balance being the fertile 238U isotope. Conventional light water reactors are typically refueled every 12 to 18 months by replacement of used fuel by fresh fuel enriched in the fissile isotope to 3% to 5%. How much natural uranium needs to be processed for refueling the reactor with 25 tons of uranium oxide (UO2 ) fresh fuel enriched to 3.5% in 235U, assuming that all the fissile isotope present in the natural uranium can be recovered in the enriched fuel? How does the answer change if the enrichment process also results in the formation of a reject (tailings) stream containing 0.1% 235U? All concentrations are on a mass basis.