How do you determine the mass of a mole of a substance?

The mass of a mole of a substance is determined by its molar mass, which is the mass of one mole of that substance.

The molar mass of a substance is a fundamental concept in chemistry. It is defined as the mass of one mole of a substance and is usually expressed in grams per mole (g/mol). The molar mass is numerically equal to the relative atomic mass (for elements) or the relative formula mass (for compounds) of the substance, but it is important to remember that while the relative atomic or formula mass is a dimensionless quantity (it has no units), the molar mass is a measure of mass and therefore has units (g/mol).

To determine the molar mass of an element, you simply look at the atomic mass of the element on the periodic table. For example, the atomic mass of carbon is approximately 12.01, so the molar mass of carbon is 12.01 g/mol.

For a compound, you add up the molar masses of all the atoms in its formula. For example, to find the molar mass of water (H2O), you would add the molar mass of hydrogen (approximately 1.01 g/mol) times 2 (because there are two hydrogen atoms in water) to the molar mass of oxygen (approximately 16.00 g/mol). So, the molar mass of water is approximately (2*1.01) + 16.00 = 18.02 g/mol.

In summary, the molar mass of a substance, which is the mass of one mole of that substance, can be determined from the atomic or formula mass of the substance. This is a key concept in chemistry, as it allows us to convert between the mass of a substance and the number of moles of that substance, which is often more useful in chemical calculations.