How do you calculate the formula mass from molar quantities?

To calculate the formula mass from molar quantities, you multiply the molar quantity by the molar mass of the substance.

In more detail, the formula mass (also known as molecular mass) of a substance is the sum of the atomic masses of all the atoms in its formula. The molar mass is the mass of one mole of a substance, and it is usually measured in grams per mole (g/mol). The molar quantity is the number of moles of a substance.

To calculate the formula mass from molar quantities, you need to know the molar mass of the substance. This can be found on the periodic table, where the molar mass of an element is given under its symbol. For a compound, you add up the molar masses of all the elements in its formula.

Once you have the molar mass, you multiply it by the molar quantity to get the formula mass. For example, if you have 2 moles of water (H2O), the molar mass of water is 18.015 g/mol (1.008 g/mol for hydrogen and 15.999 g/mol for oxygen). So, the formula mass of 2 moles of water is 2 * 18.015 g/mol = 36.03 g.

Remember, the formula mass is a measure of the amount of matter in a substance, while the molar quantity is a measure of the number of particles in a substance. By multiplying the molar quantity by the molar mass, you are effectively converting from a count of particles to a measure of mass.