Bauxite ore contains aluminum oxide, which is decomposed using electricity to produce aluminum metal. How many moles of aluminum metal can be produced if 100 g of oxygen is released?

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Answer 1 · 2016-04-01T22:22:54

You can produce #"8.33 mol of Al"# from #"100 g of O"_2#.

There are three steps to answering this type of stoichiometry problem.

Write the balanced equation for the reaction.
Use the molar mass of #"O"_2# to convert grams of #"O"_2# to moles of #"O"_2#.
Use the molar ratio from the balanced equation to convert moles of #"O"_2# to moles of #"Al"#.

Step 1. Write the balanced equation.

#"2Al"_2"O"_3 → "4Al" + "3O"_2#

Step 2. Convert grams of #"O"_2# to moles of #"O"_2#.

The molar mass of #"O"_2# is 16.00 g/mol.

#100 cancel("g O"_2) × ("1 mol O"_2)/(16.00 cancel("g O"_2)) = "6.250 mol O"_2#

Step 3. Use the molar ratio to calculate the moles of #"Al"#.

From the balanced equation, the molar ratio is #"4 mol Al":"3 mol O"_2#.

#6.250 cancel("mol O"_2) × ("4 mol Al")/(3 cancel("mol O"_2)) = "8.33 mol Al"#

You can produce #"8.33 mol of Al"#.

Here's an interesting video on stoichiometry involving grams-to moles calculations.