Question

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?

Answer 1

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

Explanation:

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

1. Write the balanced equation for the reaction.
2. Use the molar mass of `"O"_2` to convert grams of `"O"_2` to moles of `"O"_2`.
3. 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.