The mole

Front

What is the mole?

Back

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

Front

Why is the mole used to measure atoms?

Back

Atoms are extremely tiny particles, and their size varies from element to element.

Front

What is molar mass?

Back

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

Front

How do you calculate the molar mass of a compound?

Back

To calculate the molar mass, add together the atomic masses of all the atoms in the compound's formula.

Front

What is the molar mass of CO2?

Back

The molar mass of CO2 (carbon dioxide) is 44 grams/mol (12 g/mol for carbon + 16 g/mol for each oxygen x 2).

Front

What is the molar mass of NaCl?

Back

The molar mass of NaCl (sodium chloride) is 58 grams/mol (22.99 g/mol for sodium + 35.45 g/mol for chlorine).

Front

What is the molar mass of H2O?

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The molar mass of H2O (water) is 18 grams/mol (2 x 1.01 g/mol for hydrogen + 16 g/mol for oxygen).

Front

How many moles are in 200 grams of Iodine (I)?

Back

To find the number of moles, divide the mass by the molar mass of iodine (126.90 g/mol). 200 g / 126.90 g/mol = 1.57 moles.

Front

How many atoms are in one mole of a substance?

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One mole of any substance contains approximately 6.02 x 10^23 entities, known as Avogadro's number.

Front

What is Avogadro's number?

Back

Avogadro's number is 6.02 x 10^23, which is the number of atoms, molecules, or particles in one mole of a substance.