Moles Calculations

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 the same number of entities (atoms, molecules, ions, etc.) as there are in 12 grams of carbon-12.

Front

How do you calculate the number of formula units in a sample?

Back

To calculate the number of formula units, use the formula: Number of formula units = moles × Avogadro's number (6.022 x 10^23).

Front

What is Avogadro's number?

Back

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

Front

How do you convert grams to moles?

Back

To convert grams to moles, use the formula: Moles = mass (g) / molar mass (g/mol).

Front

What is the molar mass of C8H18 (octane)?

Back

The molar mass of C8H18 is approximately 114.22 g/mol.

Front

How do you find the mass of a substance from moles?

Back

To find the mass from moles, use the formula: Mass (g) = moles × molar mass (g/mol).

Front

What is the mass of 5.90 moles of C8H18?

Back

The mass is 673 g.

Front

How do you calculate the mass of a certain number of atoms?

Back

To calculate the mass of a certain number of atoms, first convert atoms to moles using: Moles = number of atoms / Avogadro's number, then use: Mass = moles × molar mass.

Front

What is the molar mass of carbon (C)?

Back

The molar mass of carbon is approximately 12.01 g/mol.

Front

How many formula units are in 2.5 moles of NaCl?

Back

There are 1.5 x 10^24 formula units in 2.5 moles of NaCl.