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Calculations for the molecular weight of Na ₂S ₂O ₅ and K ₂S ₂O ₅

Determination of the molecular weights of Na ₂S ₂O ₅ and K ₂S ₂O ₅ (sodium or potassium bisulphite) and SO ₂ (sulphur dioxide)

The atomic weight for the element sodium (Na) = 23
The atomic weight for the element sulphur (S) = 32
The atomic weight for the element oxygen (O) = 16

Since there are 2 atoms of Na (sodium), 2 atoms of S (sulphur) and 5 atoms of O (oxygen) in Na ₂S ₂O ₅,

the molecular weight of Na ₂S ₂O ₅ = (2 x 23) + (2 x 32) + (5 x 16) = 190

The atomic weight for the element potassium (K) is approximately 39

Therefore - the molecular weight of K ₂S ₂O ₅ = (2 x 39) + (2 x 32) + (5 x 16) = 222

Try to calculate the molecular weight of SO₂