1. Done By: Eric Seow

2. • Masses of particles are often numbers which are very
small and inconvenient
• Relative mass is used in practice by chemists

3. • Lightest atom is the hydrogen atom
• One nitrogen atom is 14 times heavier than a hydrogen
atom; nitrogen has a relative atomic mass of 14
• One iron atom is 56 times heavier than a hydrogen atom;
iron has a relative atomic mass of 56

4. • Molecules consist of atoms joined together
• Relative molecular mass is the average mass fo one
molecule of a substance when compared with 1/12 of the
mass of one atom of carbon-12
• Symbol is M1

5. • Is found by adding up the relative atomic masses of all
the atoms in the forumla

6. • Can be calculated from the formula of a compound
• Can be calculated from the relative atomic mass of the
elements of the compound

7. • Knowing the mass of an element in a compound, the
mass of the element in a sample of the compound can be
calculated

8. • Some compounds contain water
• Said to be hydrated
• Have H20 in their formula
• Formula is CuSO4.5H2O
• The mass of water in a compound can then be calculated
•