Moles Review

Front

What is a mole in chemistry?

Back

A mole is a unit of measurement used to express the amount of a substance. It is defined as the amount of substance that contains as many entities (atoms, molecules, etc.) as there are in 12 grams of carbon-12.

Front

What is the formula to calculate molar mass?

Back

Molar mass is calculated by summing the atomic masses of all atoms in a molecule, expressed in grams per mole (g/mol).

Front

What is the empirical formula?

Back

The empirical formula is the simplest whole-number ratio of atoms of each element in a compound.

Front

How do you calculate the percentage composition of an element in a compound?

Back

Percentage composition is calculated by dividing the mass of the element in one mole of the compound by the molar mass of the compound, then multiplying by 100.

Front

What is Avogadro's Number?

Back

Avogadro's Number is 6.022 x 10^23, which is the number of atoms, molecules, or particles in one mole of a substance.

Front

What is the molar mass of water (H2O)?

Back

The molar mass of water is approximately 18.02 g/mol.

Front

How do you convert grams to moles?

Back

To convert grams to moles, divide the mass of the substance (in grams) by its molar mass (in g/mol).

Front

What is the significance of the molar volume of a gas at STP?

Back

At standard temperature and pressure (STP), one mole of an ideal gas occupies 22.4 liters.

Front

What is the difference between molecular formula and empirical formula?

Back

The molecular formula shows the actual number of atoms of each element in a molecule, while the empirical formula shows the simplest ratio of these atoms.

Front

How do you find the molar mass of a compound like CaCl2?

Back

To find the molar mass of CaCl2, add the molar mass of calcium (40.08 g/mol) and twice the molar mass of chlorine (35.45 g/mol), resulting in 110.98 g/mol.