Final answer:
It is true that the percent composition of a compound can be calculated from its chemical formula. This involves using atomic masses and subscripts from the formula to calculate the mass contribution of each element and dividing by the molar mass of the whole compound.
Step-by-step explanation:
True, you can calculate the percent composition of a compound if you know only the chemical formula. The calculation is based on the fact that the formula provides the number of atoms of each element present in the compound, known as subscripts. For instance, in water (H2O), there are two atoms of hydrogen and one atom of oxygen.
- To determine the percent composition, you first calculate the mass of each element in one mole of the compound using the atomic masses of the elements and the subscripts from the formula.
- Then, you divide the mass of each element by the molar mass of the whole compound.
- Finally, you multiply the result by 100% to obtain the percent composition.
This process can be applied to any compound, provided its chemical formula is known, allowing the determination of how much each element contributes to the total mass of the compound.