In a chemical reaction, an insufficient quantity of any of the reactants will limit the amount of product that forms. The determines the amount of product that can be formed. The reactant that is not completely used up in a reaction is called the:.

EXCESS or NON-LIMITING REAGENTS

Explanation:

Reagents not completely used up in a chemical reaction are said to be in excess or non-limiting.

They are said to be excess because the amount of reactants present in the reaction doesn't in any way affect OT limit the products formed.

While reactants that are completely used up in a chemical reaction are said to be limiting reactants. The reactants have a definite amount of moles called stoichiometric amount and once the amount is used up, the formation of products is hindered.

altitude, density, pressure

air gets less dense the higher the altitude and also the air pressure is less as altitude rises.