Final answer:
To calculate the percent composition of BaCl₂, divide the molar mass of each element by the compound's total molar mass and multiply by 100%. The composition is 65.94% Ba and 34.06% Cl.
Step-by-step explanation:
The percent composition of a compound like BaCl2 (barium chloride) can be calculated by determining the mass of each element in the compound and then dividing by the total molecular mass. First, calculate the molar masses: Ba = 137.33 g/mol, Cl = 35.45 g/mol (x2 for two Cl atoms). Next, add these to get the molecular mass of BaCl2: 137.33 g/mol + 70.90 g/mol = 208.23 g/mol. Then, divide the mass of each element by the molecular mass and multiply by 100 to get the percent composition.
For Ba: (137.33 g/mol / 208.23 g/mol) x 100% = 65.94%
For Cl: (70.90 g/mol / 208.23 g/mol) x 100% = 34.06% (This is for both Cl atoms combined.)