Chemistry Reflection, Ar and Mr

Relative Atomic Mass (Ar):
It is the average mass of an atom in an element. For example: Na=23g/mol

Relative Molecular Mass (Mr):
It is the sum of masses of elements present in a compound. The relative molecular mass can be used to predict the mass of the product of certain elements.

Ex: CO2
C=12 x 1= 12
O=16 x 2= 32
 32+12=44 g/mol

SO4
S=32 x 1= 32
O=16 x 4=64
64+32=96 g/mol

H20
H= 1 x 2=2
O=16 x 1=16
16 +2= 18 g/mol