Unit 5: moles

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

How do you calculate the number of moles from grams?

Back

To calculate the number of moles from grams, use the formula: Moles = Mass (g) / Molar Mass (g/mol).

Front

What is Avogadro's number?

Back

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

Front

How many moles are in 19.5 grams of Sodium (Na)?

Back

0.85 moles (using the molar mass of Sodium, which is approximately 22.99 g/mol).

Front

How many molecules are in 9.44 moles of AlCl3?

Back

5.68 x 10^24 molecules of AlCl3 (calculated using Avogadro's number).

Front

What is the molar mass of AuCl3?

Back

303.3 g (calculated from the atomic masses of gold and chlorine).

Front

How many moles are in 32.3 grams of carbon dioxide (CO2)?

Back

0.734 moles (using the molar mass of CO2, which is approximately 44.01 g/mol).

Front

What is the conversion factor for moles to particles?

Back

1 mole = 6.02 x 10^23 particles.

Front

How do you find the molar mass of a compound?

Back

To find the molar mass, sum the atomic masses of all the atoms in the compound's formula.

Front

What is the relationship between moles and volume at STP?

Back

At standard temperature and pressure (STP), 1 mole of an ideal gas occupies 22.4 liters.