The chemical reaction is:
S + O2 --> SO2
First, let's find out the mass of sulfur in grams.
Let's transform 9.8 x 10^6 tons into grams. Let's multiply by 10^6:
9.8 x 10^12 g of coal.
2% of it is sulfur, so:
9.8 x 10^12 g of coal --- 100%
x g of sulfur --- 2%
x = 1.96 x 10^11 g of Sulfur
Now let's transform it to moles using the following formula: moles = mass/molar mass
molar mass of S:
moles = 1.96 x 10^11/32
moles = 6.125 x 10^9 moles of S
The reaction ratio between S and SO2 is 1:1, so it is emitted 6.125 x 10^9 moles of SO2 as well.
Let's transform it to mass using the following formula:
mass = moles x molar mass
molar mass of SO2: 64 g/mol
mass = 6.125 x 10^9 x 64
mass = 3.92 x 10^11 g
Let's transform it to tons:
3.92 x 10^11/10^6 = 3.92 x 10^5 tons
Answer: 3.92 x 10^5 tons