how many grams of chloride are found in 72.03mg of magnesium chlorate?

26.73 mg.

Explanation:

no. of moles of magnesium chlorate (Mg(ClO₃)₂) = mass/molar mass = (72.03 mg)/(191.21 g/mol) = 0.377 mmol.

Every 1.0 mole of magnesium chlorate (Mg(ClO₃)₂) contains 2.0 moles of Cl.

∴ The no. of moles of Cl in magnesium chlorate (Mg(ClO₃)₂) = 2(0.377 mmol) = 0.754 mmol.

∴ The mass of Cl are found in 72.03 mg of magnesium chlorate (Mg(ClO₃)₂) = (no. of moles of Cl)(atomic mass of Cl) = (0.754 mmol)(35.453 g/mol) = 26.73 mg.