If 5.3 g of gallium reactions with 5.3 g of oxygen according to the following reaction, how
many grams of gallium oxide can be produced?

Word equation:
Formula equation:
(Must be balanced!)

7.5g

Explanation:

Given parameters:

Mass of gallium = 5.3g

Mass of oxygen  = 5.3g

Unknown:

Mass of gallium oxide produced  = ?

Solution:

To solve this problem, let us write the reaction equation:

   Gallium reacts with oxygen to produce gallium oxide

                     4Ga     +   3O₂     →   2Ga₂O₃

Let us determine the limiting reactant from the equation. This reactant is the one in short supply and it determines the extent of the reaction.

        Number of moles  =

  Number of moles of Ga  =   = 0.08mole

   Number of moles of O₂ =   = 0.17mole

From the balance reaction equation;

                4 moles of Ga reacted with 3 moles of O₂

               0.08 moles of Ga will require     = 0.06 moles of O₂

But we were given 0.17 moles. This implies that oxygen gas is in excess

  If :

             4 moles of Ga gives 2 moles of Ga₂O₃

           0.08 moles of Ga will produce   = 0.04moles

Mass of Ga₂O₃ = number of moles x  molar mass

         Molar mass of Ga₂O₃ = 2(69.7)  + 3(16)  = 187.4g/mol

     Mass of Ga₂O₃ = 0.04 x 187.4 = 7.5g

< > according to newton's third law of motion, forces always act in equal but opposite pairs. another way of saying this is for every action, there is an equal but opposite reaction.< >