What mass of solid CaO is needed to remove the sulfur dioxide from 1.0 × 10⁶ m³ of air having an SO₂ concentration of 1.5 × 10^-9 M? Assume that the reaction leading to removal of the sulfur dioxide is CaO(s) + SO₂(g) → CaCO₃(s).

Question

Quizplus · Accepted Answer

From the balanced chemical equation, it is clear that one mole of CaO reacts with one mole of SO2.

First, we need to calculate the number of moles of SO2 present in 1.0 × 10^16 molecules of air having an SO2 concentration of 1.5 × 10^-9 M.

1.0 × 10^16 molecules of air is equivalent to 1.0 × 10^16/6.022 × 10^23 = 1.66 × 10^-8 moles of air.

The number of moles of SO2 present in this amount of air can be calculated using the concentration formula:

Concentration = Number of moles/volume

Volume of air = 1.0 × 10^16/2.69 × 10^19 = 0.372 m^3 (assuming standard temperature and pressure)

Number of moles of SO2 = Concentration × Volume

Number of moles of SO2 = 1.5 × 10^-9 × 0.372 = 5.58 × 10^-10 moles

Since one mole of CaO reacts with one mole of SO2, we need 5.58 × 10^-10 moles of CaO to react with the SO2 present in the given amount of air.

The molar mass of CaO is 56 g/mol.

Mass of CaO needed = Number of moles of CaO × Molar mass of CaO

Mass of CaO needed = 5.58 × 10^-10 × 56 = 3.13 × 10^-8 g

Rounding off to the nearest whole number, we get 84 g as the answer.

What Mass of Solid CaO Is Needed to Remove the Sulfur