How is the molecular weight of a compound calculated?

The molecular weight of a compound is determined by summing the atomic weights of all the atoms present in its chemical formula. Each element in the compound contributes its atomic weight, which is found on the periodic table. To calculate the molecular weight accurately, you multiply the atomic weight of each element by the number of times that element appears in the molecular formula and then add these values together.

For example, in water (H2O), you would take the atomic weight of hydrogen (approximately 1.01 g/mol), multiply it by 2 (since there are two hydrogen atoms), and then add the atomic weight of oxygen (approximately 16.00 g/mol). This results in a molecular weight of about 18.02 g/mol for water.

Other answer choices do touch upon concepts related to molecular weight but do not define it correctly. Averaging atomic weights or dividing molecular and empirical formulas does not directly relate to the process of calculating molecular weight as required by the question.