Stoichiometry-using the ratios-part 3
So if we know the mole of any species in a chemical equation we can find the mole of all the others, simply by applying the ratio.

Consider the problem given below.

How many mole of AlCl3 are formed if 4 mole of NaNO3 are also formed?

From the equation we see that for every 3 mole of NaNO3 formed 1 mole of AlCl3 is formed.

So we take the 4 mole of NaNO3 and multiply it by 1/3 to get the mole of AlCl3

 

Consider the problem given below.
From the reaction:
B2H6 + 3O2 => 2HBO2 + 2H2O

What mass of O2 will be needed to burn 55.2 g of B2H6?

Play the video on the right for solution.

Consider the problem given below.
From the reaction:
B2H6 + 3O2 => 2HBO2 + 2H2O

Calculate the number of O2 molecules that are needed to produce will be needed to burn 20.5 g of H2O.

Play the video on the right for solution.

 

 
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