Unit 6-Review The Mole

Front

What is the percent by mass of oxygen in MgO?

Back

40%

Front

What is the percent by mass of potassium in KCl?

Back

52.7%

Front

What is an empirical formula?

Back

The simplest whole-number ratio of moles of elements in the compound.

Front

What is the mole used for?

Back

To measure the amount of atoms or molecules in a substance.

Front

How many moles are in 4.5x10^24 particles?

Back

7.48 mol.

Front

Define 'mole' in chemistry.

Back

A mole is a unit that measures the amount of substance, defined as containing exactly 6.022 x 10^23 particles.

Front

What is the formula to calculate percent by mass?

Back

(mass of element in 1 mole of compound / molar mass of compound) x 100.

Front

What is the molar mass of MgO?

Back

24.31 g/mol (Mg) + 16.00 g/mol (O) = 40.31 g/mol.

Front

How do you convert moles to particles?

Back

Multiply the number of moles by Avogadro's number (6.022 x 10^23).

Front

What is the significance of Avogadro's number?

Back

It defines the number of particles in one mole of a substance.