Limiting Reactants and Percent Yield

This video tutorial covers the concept of limiting reactants in chemistry, using a peanut butter and jelly sandwich analogy to explain how the amount of product is limited by the reactant that is used up first. It also discusses how to identify limiting and excess reactants through example problems. The tutorial introduces the concept of percent yield, explaining how it compares actual yield to theoretical yield, and provides an example problem to illustrate the calculation of percent yield.

What is the limiting reactant in a chemical reaction?

• The reactant that is present in the largest amount

• The reactant that is left over after the reaction

• The reactant that does not participate in the reaction

• The reactant that is completely used up first

In the sandwich analogy, what does the bread represent?

• The excess reactant

• The limiting reactant

• The catalyst

• The product

How do you determine the limiting reactant in a chemical equation?

• By using the reactant that appears first in the equation

• By identifying the reactant with the highest molar mass

• By calculating the amount of product each reactant can produce

• By comparing the initial amounts of reactants

What is the excess reactant in a chemical reaction?

• The reactant that speeds up the reaction

• The reactant that is left over after the reaction

• The reactant that is completely used up first

• The reactant that is present in the smallest amount

If you have 6 moles of dinitrogen tetrahydride and 4.5 moles of hydrogen peroxide, which is the limiting reactant?

• Both are limiting

• Neither is limiting

• Hydrogen peroxide

• Dinitrogen tetrahydride

What is the percent yield in a chemical reaction?

• The ratio of actual yield to theoretical yield, multiplied by 100

• The ratio of theoretical yield to actual yield, multiplied by 100

• The amount of reactant used in moles

• The amount of product formed in grams

What does a percent yield of 50% indicate?

• The reaction was 50% complete

• Half of the theoretical yield was achieved

• Half of the reactants were used

• The product was 50% pure

In the photosynthesis example, what is the limiting reactant?

• Glucose

• Water

• Oxygen

• Carbon dioxide

How do you calculate the theoretical yield in a chemical reaction?

• By measuring the actual yield in the lab

• By using the balanced chemical equation and molar ratios

• By estimating based on reactant amounts

• By using the smallest reactant amount

What is the first step in calculating percent yield?

• Measure the excess reactant

• Find the limiting reactant

• Calculate the theoretical yield

• Determine the actual yield