Question

When coal is burned, the sulfur it contains is converted into sulfur dioxide. This SO2 is a serious pollutant, so it needs to be removed before it escapes from the stack of a coal fired plant. One way to remove the SO2 is to add limestone, which contains calcium carbonate, CaCO3, to the coal before it is burned. The heat of the burning coal converts the CaCO3 to calcium oxide, CaO. The calcium oxide reacts with the sulfur dioxide in the following reaction:

2CaO + 2SO2 + O2 → 2CaSO4

a. The solid calcium sulfate does not escape from the stack as the gaseous sulfur dioxide would. What mass of calcium sulfate forms for each 1893 kg of SO2 removed by this technique?

Answer 1

2CaO + 2SO2 + O2 → 2CaSO4

In the above reaction equation:

   2 moles of SO2 produces 2 moles of CaSO4
or 1 moles of SO2 produces 1 moles of CaSO4

Mass of SO2 = 1893 Kg = 1893000 g
​Molar mass of SO2 = 64 g/mol
So, 64 g of SO2 = 1 mol
1 g of SO2 = (1/64) mol
1893000 g of SO2 = (1893000/64) mol = 29578.125​ mol

So, moles of CaSO4 produced = 29578.125 mol
Molar mass of CaSO4 = 136 g/mol
So, 1 mol of CaSO4 = 136 g
29578.125 mol of CaSO4 = 29578.125 x 136 g
​ = 4022625 g
   = 4022.625 Kg
= 4023 Kg