Moles

Front

What is a mole?

Back

A mole is a unit of measurement in chemistry that represents 6.022 x 10²³ particles (atoms, molecules, ions, etc.). It is used to quantify the amount of substance.

Front

How do you calculate the mass of a substance in grams from moles?

Back

Mass (g) = Moles × Molar Mass (g/mol).

Front

What is the molar mass of B₂(Cr₂O₇)₃?

Back

The molar mass of B₂(Cr₂O₇)₃ is approximately 394.19 g/mol.

Front

How many moles are in 4.5 x 10²⁴ particles?

Back

0.747 moles.

Front

What is the empirical formula?

Back

The empirical formula is the simplest whole-number ratio of elements in a compound.

Front

How do you find the empirical formula from percentage composition?

Back

Convert the percentages to grams, then to moles, and find the simplest ratio.

Front

What is the empirical formula for a compound with 72.2% magnesium and 27.8% nitrogen?

Back

Mg₃N₂.

Front

How do you convert grams to moles?

Back

Moles = Mass (g) / Molar Mass (g/mol).

Front

How many molecules are in 69.0 moles of SrO?

Back

4.16 x 10²⁵ molecules.

Front

What is Avogadro's number?

Back

Avogadro's number is 6.022 x 10²³, the number of particles in one mole of a substance.