Introducing Conversions of Masses, Moles, and Number of Particles (3.2.2)

Question 1

• The molar mass of a substance represents the mass of one mole of that substance.

Answer 1

• The molar mass of a substance represents the mass of one mole of that substance.

Question 2

• The molar mass of a substance can be used as a conversion factor between mass and moles.

Answer 2

• The molar mass of a substance can be used as a conversion factor between mass and moles.

Question 3

The molar mass of a substance represents the
mass of one mole of that substance. The molar
masses of elements can be found on the periodic
table.

For example, the molar mass of fluorine (F) is
18.998403 g/mol. One mole of fluorine has a mass
of 18.998403 g.

Molar masses are additive. To find the mass of one
mole of potassium fluoride (KF), simply add together
the masses of potassium and fluoride. The molar
mass of potassium fluoride is 58.0967 g/mol.

The molar mass of a more complex molecule such
as ethanol (C2H5OH) can be found by multiplying
the number of atoms of each element by the
element’s molar mass and summing these individual
masses. The molar mass of ethanol is 46.069 g/mol.

Answer 3

The molar mass of a substance represents the
mass of one mole of that substance. The molar
masses of elements can be found on the periodic
table.

For example, the molar mass of fluorine (F) is
18.998403 g/mol. One mole of fluorine has a mass
of 18.998403 g.

Molar masses are additive. To find the mass of one
mole of potassium fluoride (KF), simply add together
the masses of potassium and fluoride. The molar
mass of potassium fluoride is 58.0967 g/mol.

The molar mass of a more complex molecule such
as ethanol (C2H5OH) can be found by multiplying
the number of atoms of each element by the
element’s molar mass and summing these individual
masses. The molar mass of ethanol is 46.069 g/mol.

Question 4

The molar mass of a substance can be used as a
conversion factor between mass and moles.

For example, to find the mass of 0.9628 moles of
iron, simply multiply 0.9628 mol by the molar mass
of iron (55.845 g/mol).

Notice that the mass of 0.9628 moles of iron is
lower than the mass of one mole of iron. This
makes sense, because 0.9628 is less than one.

Answer 4

The molar mass of a substance can be used as a
conversion factor between mass and moles.

For example, to find the mass of 0.9628 moles of
iron, simply multiply 0.9628 mol by the molar mass
of iron (55.845 g/mol).

Notice that the mass of 0.9628 moles of iron is
lower than the mass of one mole of iron. This
makes sense, because 0.9628 is less than one.