Limiting and Excess Reactants in Reactions

This video tutorial introduces students to stoichiometric and non-stoichiometric mixtures in chemistry. It explains the concepts of limiting and excess reactants and demonstrates how to determine if a reaction mixture is stoichiometric through examples. The session concludes with an assignment for further practice.

What is a characteristic of a stoichiometric mixture?

• The reaction never stops.

• There is always an excess reactant.

• The reactants are totally consumed.

• The reactants are partially consumed.

In a non-stoichiometric mixture, what happens to the limiting reactant?

• It remains unchanged.

• It is totally consumed.

• It is partially consumed.

• It increases in quantity.

How do you determine if a reaction mixture is stoichiometric?

• By observing the color change.

• By measuring the temperature change.

• By checking if the reactants are in excess.

• By comparing the ratios of the reactants.

What is the ratio of C2H2 to O2 in a stoichiometric mixture for the given reaction?

• 1:5

• 2:5

• 4:10

• 2:2

How many moles of CO2 are produced from 4 moles of C2H2 in a stoichiometric reaction?

• 10 moles

• 2 moles

• 8 moles

• 4 moles

In a non-stoichiometric mixture, which reactant is the limiting reactant?

• The one that is not consumed.

• The one that is in excess.

• The one with the lower initial moles.

• The one with the higher initial moles.

How many moles of O2 are reacted in the non-stoichiometric example?

• 3 moles

• 0.5 moles

• 1 mole

• 2.5 moles

What is the remaining amount of O2 in the non-stoichiometric reaction?

• 3 moles

• 1 mole

• 2 moles

• 0.5 moles

What is the molar mass of Cl as given in the assignment?

• 56

• 35.5

• 16

• 40

What is the chemical equation provided in the assignment for further practice?

• N2 + 3H2 → 2NH3

• C + O2 → CO2

• 2H2 + O2 → 2H2O

• CaO + 3C → CaC2 + CO