Final answer:
The mass percent composition of Ca in CaCl₂ is 36.10%, and for Cl, it is 63.90%. This is calculated by dividing the molar mass of each element by the molar mass of the compound and multiplying by 100%.
Step-by-step explanation:
To find the mass percent composition of Ca (calcium) and Cl (chlorine) in calcium chloride (CaCl₂), you divide the mass of the individual element in 1 mole of the compound by the molar mass of the compound and multiply by 100%.
The molar mass of CaCl₂ is the sum of the molar masses of 1 mole of calcium and 2 moles of chlorine, which equals:
- 40.08 g/mol (Ca)
- + 35.45 g/mol (Cl) × 2 = 70.90 g/mol (Cl)
This gives us a molar mass of 110.98 g/mol for CaCl₂.
To calculate the mass percent of calcium, divide the molar mass of calcium by the molar mass of CaCl₂ and multiply by 100%:
(40.08 g/mol ÷ 110.98 g/mol) × 100% = 36.10%
For chlorine, divide the combined molar mass of chlorine by the molar mass of CaCl₂ and multiply by 100%:
(70.90 g/mol ÷ 110.98 g/mol) × 100% = 63.90%
The percent composition of CaCl₂ is therefore 36.10% Ca and 63.90% Cl.