FINDING OUT HOW MUCH OF A CHEMICAL REACTS

I When the definite proportions fora given reaction are known, unit conversion (see the Calculation Comer on page 12) can help you determin e the amount of a chemical that takes part in the reaction. For instance, we can express the law of definite proportions for the formation of water as 

From this relationship, we can derive two conversion factors  

If you are given a certain amount of one element and want to know how much of the other element is needed for a complete reaction, you need only multiply by the appropriate conversion factor to find the answer. 

How much hydrogen is needed in order for 64 grams of oxygen to react completely in the formation of water  

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