Work out excess reagent instantly with clear inputs, formula shown and shareable results.
Once the limiting reagent is known, the excess reagent's fate is fixed: it is consumed in strict stoichiometric proportion to the limiter and whatever remains is unreacted. Charging 8 mol where 3 mol of limiter needs 2 mol each means 6 mol reacts and 2 mol is left, a 33% excess over requirement.
Amount required
required = limiting moles x ratio
Leftover
excess left = available - required
If it appears, the reagent you called excess is actually the limiter - the charge is below the stoichiometric requirement.
To push an equilibrium forward or to protect an expensive reagent by making the cheap one the excess.