10 atoms of aluminum reacts with 6 molecules of oxygen gas to produce aluminum oxide. 4 Al + 3 O2 - -> 2 Al2O3 What is the excess reactant?

Oxygen

Aluminum

Aluminum oxide

Cannot tell

The excess reactant is Aluminum.

Explanation:

We have to write the balanced equation as,

4 Al + 3 O₂ → 2 Al₂O₃

According to the molar ratio 4: 3, from the given balanced equation, we can say that 4 atoms of Al reacted with 3 molecules of oxygen.

Given that 10 atoms of aluminum reacts with 6 molecules of oxygen, as per the ratio only 8 atoms of Aluminum is required to react with 6 molecules of oxygen, so excess reactant is Aluminum.