Limiting Reactants and Chemical Reactions

This video tutorial focuses on identifying limiting reactants in chemical reactions. It covers the concept of limiting reactants using examples involving zinc and hydrochloric acid, as well as ethane and oxygen. The tutorial explains how to determine the limiting reactant by comparing the quantity per coefficient ratio and converting grams to moles. It also discusses the theoretical yield of products based on the limiting reactant.

What is a limiting reactant?

• A reactant that is always in the smallest quantity

• A reactant that does not participate in the reaction

• A reactant that determines the amount of product formed

• A reactant that is present in excess

In the reaction between zinc and hydrochloric acid, what is the balanced chemical equation?

• Zn + HCl → H2 + ZnCl

• Zn + 2HCl → H2 + ZnCl2

• 2Zn + HCl → H2 + 2ZnCl2

• Zn + HCl2 → H2 + ZnCl

How do you determine the limiting reactant using the quantity per coefficient ratio?

• By finding the reactant with the highest quantity per coefficient ratio

• By comparing the volumes of the reactants

• By finding the reactant with the lowest quantity per coefficient ratio

• By comparing the masses of the reactants

If you have 3 moles of zinc and 4 moles of HCl, which is the limiting reactant?

• Both are limiting reactants

• HCl

• Neither is a limiting reactant

• Zinc

Why can't you determine the limiting reactant by just comparing the masses of the reactants?

• Because the densities of reactants are different

• Because the masses of reactants are always equal

• Because the molar masses of reactants are different

• Because the volumes of reactants are different

In the reaction between ethane and oxygen, what is the balanced chemical equation?

• C2H6 + O2 → CO2 + H2O

• C2H6 + 2O2 → 2CO2 + 3H2O

• 2C2H6 + 7O2 → 4CO2 + 6H2O

• 2C2H6 + 5O2 → 4CO2 + 6H2O

How do you identify the limiting reactant in a reaction involving ethane and oxygen?

• By comparing the initial masses of the reactants

• By converting the moles of each reactant to the moles of product

• By comparing the volumes of the reactants

• By comparing the densities of the reactants

What is the theoretical yield of CO2 if 5 moles of ethane react with 16 moles of oxygen?

• 10 moles

• 9.14 moles

• 8 moles

• 7.5 moles

When converting grams of reactants to grams of products, what is the first step?

• Use the mole ratio to convert between substances

• Compare the masses of the reactants

• Convert moles to grams using the molar mass

• Convert grams to moles using the molar mass

If you have 30 grams of ethane and 84 grams of oxygen, which reactant is limiting?

• Oxygen

• Neither is a limiting reactant

• Both are limiting reactants

• Ethane