The relationship between the number of moles of a

substance with its mass

Relate to Avogadro Constant

Molar Mass

Meaning

2 kg of mangosteen

50 g of flower

3 kg of papaya

Amount of substanceMass

Mass of one mole of element or compound in gram

Molar mass

Unit

Gram per mol (g/mol)

MOLAR MASS OF AN ELEMENT

is found by looking at the atomic mass of the element on the periodic table

Molar mass = (RAM) Relative Atomic Mass= (RMM) Relative Molecular

Mass

Calcium = 40 g

Cobalt = 59g

Iron = 56 g

Bromine = 80g1 mole element

MOLAR MASS OF A CHEMICAL COMPOUND

Molar masses of chemical compounds are equal to the sums of the molar masses of all the atoms in one molecule of that compound

example : NaCl

molar mass = molar mass of one atom of sodium + molar mass of one atom of chlorine Answer : 58.5 g

EXAMPLE OF CHEMICAL COMPOUND

23g of sodium + 35g of chloride

=58 g

Water, H2O

Sodium Chloride, NaCl

2g hydrogen + 16g oxygen

= 18g

MOLAR MASS RELATION TO AVOGADRO CONSTANT

Molar mass = mass of 6.02 X 1023

1 mol = 6.02 X 1023

Molar mass = 1 mol mass

EXAMPLE

1 mol Aluminum has a mass of 27 g

1 mol of Aluminum contain 6.02 X 1023 atoms 6.02 X 1023 Atom of Aluminum has mass of 27g

Relative atomic mass

1 mole Aluminum

copper

watersulfur

1 mole - 18 g1 mole - 32 g

1 mole - 64 g

All this substance contain 6.02 X 1023

One mole of nails contains 6.022 x 1023 nails

One mole of screws contains 6.022 x 1023 screws

One mole of woods contains 6.022 x 1023 woods

Building of a house

SUBSTANCE

mol

Mass (g)

NA

He H2O NaCl

1 2

4.0 18.0 58.5

6.02 X 1023 6.02 X 1023

6.02 X 1023

1 Mol = 6.02 X 10 23

3

x 1 x 2 x 3

x 1 x 2 x 3