Mole to Mass & Mass to Mole

ex How many grams of Bauxite (Al2O3) are required to produce 3.5mol of pure aluminum?

Step 1 - Write a balanced equation (2Al2O3 - > 4Al + 3O2)

Step 2 - Change moles of aluminum to moles of bauxite using "what you need over what you have" (2/4)

Step 3 - Multiply the moles of bauxite by the molar mass of bauxite (1.75mol * 102g/mol)

=1.8*10^2g of bauxite

How many moles of Lead(II)Nitrate are consumed when 4.5g of sodium sulphide completely react?

Step 1 - Write a balanced equation (Pb(NO3)2 + Na2S -> PbS + 2NaNO3)

Step 2 - Change grams of sodium sulphide to moles using molar mass ( 4.5/78.1)

Step 3 - Change moles of sodium sulphide to moles of Lead(II)Nitrate using "what you need over what you have" (1/1)

= 0.058mol of Lead(II)Nitrate


- JanCarlo Paysan