Consider the following equation for a chemical reaction: 2H + O2 + 2H2O This can be interpreted as two molecules of hydrogen and one molecule of oxygen combining to form
two water molecules. But how often do chemists limit their reactions to one or two molecules? Usually a
reaction is done with an unimaginable number of molecules. How then do chemists know they have the
right mix? The molecules need to be quickly counted! How do we count molecules? The answer is the
unit called the mole. This activity will start by considering two egg farmers (a chicken farmer and a quail
farmer). They produce such large numbers of eggs that they can't count them all individually, so they
count in dozens of eggs in some cases, while in other cases they use mass. Weighing is often easier than
counting!
T
:
Model 1 - Eggs
Chicken
Number of eggs
Mass of the
in the sample sample
1
37.44 g
Ratio of
numbers
of eggs
Quail
Number of eggs Mass of the
in the sample
sample
1
2.34 g
10
Ratio of
masses
of eggs
1
1:1
16:1
10
438
438
61 40
1 dozen
1 dozen
1 million
1 million
1. Consider the data in Model 1.