Final answer:
To find the percent composition of a compound, divide the mass of each element by the total mass of the compound. In CuBr, the percent composition of Cu is 44.30% and the percent composition of Br is 55.70%. In (NH₄)₂S, the percent composition of N is 41.06%, the percent composition of H is 11.81%, and the percent composition of S is 47.13%.
Step-by-step explanation:
To find the percent composition of a compound, we need to determine the mass of each element in the compound and divide it by the total mass of the compound. Let's calculate the percent compositions of the given compounds:
a) CuBr:
- The molar mass of Cu is 63.55 g/mol and the molar mass of Br is 79.90 g/mol.
- The total mass of CuBr is 63.55 g/mol + 79.90 g/mol = 143.45 g/mol.
- The percent composition of Cu in CuBr is (63.55 g/mol / 143.45 g/mol) * 100% = 44.30%.
- The percent composition of Br in CuBr is (79.90 g/mol / 143.45 g/mol) * 100% = 55.70%.
b) (NH₄)₂S:
- The molar mass of N is 14.01 g/mol, the molar mass of H is 1.01 g/mol, and the molar mass of S is 32.07 g/mol.
- The total mass of (NH₄)₂S is (2 * 14.01 g/mol + 8 * 1.01 g/mol + 1 * 32.07 g/mol) = 68.14 g/mol.
- The percent composition of N in (NH₄)₂S is (2 * 14.01 g/mol / 68.14 g/mol) * 100% = 41.06%.
- The percent composition of H in (NH₄)₂S is (8 * 1.01 g/mol / 68.14 g/mol) * 100% = 11.81%.
- The percent composition of S in (NH₄)₂S is (1 * 32.07 g/mol / 68.14 g/mol) * 100% = 47.13%.