(stoichiometry)
the annual production of sulfur dioxide from burning coal and fossil fuels, for auto exhaust, and from other activities is about 26 million tons. how much sulfur, present in the original materials, would result in that quantity of so2?
s+o2 --> so2

So the first thing that you need to do is to find the moles in 26 tons of SO2, which will be the same amount of mols as sulphur as it is a 1:1 molar ration so it might be expressed like this:
26x10^6 tons= 26000x10^6kg= 26000000x10^6g. 

26000000x10^6/(32+32.1)= 405616x10^6 mol of SO2 and thus sulfur. times the mol by the rmm (units of g/mol). 

405616x10^6mol*32.1g/mol = 13020273x10^6g = 13020x10^6 kg = 13.02x10^6tons 

the final answer is 13 million tons. The answer is in Tones because you need to convert g into moles with this idea 1 ton= 1000kg = 1000000g. I hope this helps a lot