Determine the mass fraction of the element K2SO and N2O.

The mass of K2SO4 (potassium sulfate) = 174 grams, the mass of the compound is obtained from the sum of the masses of potassium, sulfur and oxygen 39 * 2 + 32 + 16 * 4 = 174. The compound has 174 grams and this is 100%, and the mass of potassium 78 is X%, hence X = 78 * 100/174 = 44, 82% is the mass fraction of potassium in the compound. In this way we are looking for sulfur: 174 – 100%, 32 – X; X = 32 * 100/174 = 18.39% – mass fraction of sulfur. Mass fraction of oxygen: 174 – 100%, 64 – X; X = 64 * 100/174 = 36.78%. We check our calculations: 44.82 + 18.39 + 36.78 = 100%. Mass fraction of nitrogen in N2O: 44 grams – 100%, and 28 grams – X, hence X = 63.63%. Mass fraction of oxygen: 100% – 63.63 = 36.37%.