Mole to Mole Problems

• Coefficients in balanced equations tell us the number of moles reacted or produced.
• They can also be used as conversion factors.
                                 3x + y -> 22
                                      2.0 mol
                                       1 : 2  <- ratio between y & z
  
  ratio between x & y -> 3:1
                                      6.0 mol
  
                             3x          +       y       ->    2z
                           [2.25 mol] [0.75 mol] I [1.5 mol]
                             3x          +      y        ->   2z
                           [1.2 mol]  x    [2/3]     =  [1.8 mol]
  
   
• Remember what you need over what you are given     

Example:

• Water decomposes into Hydrogen and Oxygen gas.
•  2H2O -> 2H2 = 1O2
• How many moles of Hydrogen gas are produced if 0.500 mol of water decompose?
• 0.500mol x 2/2 = 0.5000mol

Example:

• Sulphur reacts with Barium Oxide to produce Barium Sulphide and Oxygen gas.
• 1S8 + 8BaO -> 8Ba5 + 4O2
• How many moles of Sulphur are needed to completely react with 2.00 mol of Barium Oxide?
• 2.00mol x 1/8 = 0.250mol

Mole to Mole and Mass to Mass Conversions:

- George Spencer