the percent composition of potassium chloride, KCl, can be calculated from the atomic weights of potassium and chlorine and the formula weight of KCl.
Formula weight of KCl: 39.10 g + 35.45 g = 74.55 g
Percent potassium: 39.10 g K
74.55 g KCl X 100% = 52.45% potassium
Percent chlorine: 35.45 g Cl
74.55 g KCl X 100% = 47.55% chlorine
