The Mole Concept

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 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.

Front

How do you calculate the number of atoms in a given number of moles?

Back

To calculate the number of atoms, multiply the number of moles by Avogadro's number (6.02 x 10^23).

Front

What is the relationship between moles and mass?

Back

The mass of a substance in grams is equal to the number of moles multiplied by the molar mass of the substance (mass = moles x molar mass).

Front

What is molar mass?

Back

Molar mass is the mass of one mole of a substance, usually expressed in grams per mole (g/mol).

Front

How many formula units are in one mole of a compound?

Back

One mole of a compound contains 6.02 x 10^23 formula units.

Front

What is the difference between atoms, molecules, and formula units?

Back

Atoms are the basic units of elements, molecules are two or more atoms bonded together, and formula units represent the simplest ratio of ions in ionic compounds.

Front

How many moles are in 12 grams of carbon-12?

Back

There is 1 mole of carbon-12 in 12 grams.

Front

If you have 3.01 x 10^22 atoms of magnesium, how many moles do you have?

Back

0.0500 moles of magnesium.

Front

What is the number of atoms in 1.50 moles of mercury (Hg)?

Back

9.03 x 10^23 atoms of mercury.