Stoichiometry

Which of the following BEST describe the limiting reactant?

• The reactant that is used in excess.
• The reactant that is completely consumed first.
• The reactant that determines the rate of reaction.
• The reactant that is present in the smallest amount.

What is the primary purpose of identifying the limiting reactant in a chemical reaction?

• To calculate the theoretical yield of products.

• To determine the temperature of the reaction.

• To measure the pressure of the reactants.

• To identify the catalyst used in the reaction.

Which of the following statements is TRUE regarding excess reactants?

• They are completely consumed in the reaction.

• They do not affect the amount of product formed.

• They are present in greater quantities than the limiting reactant.

• They are always the most expensive reactants.

• Sodium (Na)

• Chlorine (Cl₂)

• Sodium chloride (NaCl)

• None of these

• 5 moles

• 10 moles

• 15 moles

• 20 moles

In a chemical reaction, what happens to the limiting reactant once it is completely consumed?

• The reaction stops.

• The reaction continues with excess reactants.

• More limiting reactant is produced.

• It becomes the excess reactant.

What is the effect of increasing the amount of the limiting reactant in a chemical reaction?

• It increases the yield of products.

• It has no effect on the yield of products.

• It decreases the rate of reaction.

• It changes the reaction to a different type.

How can you determine the theoretical yield of a product in a chemical reaction?

• By measuring the mass of the limiting reactant.

• By calculating the total mass of all reactants.

• By observing the color change during the reaction.

• By using the amount of excess reactant available.

What is the significance of the stoichiometric coefficients in a balanced chemical equation?

• They indicate the physical state of the reactants.

• They represent the ratio of moles of reactants and products.

• They determine the temperature at which the reaction occurs.

• They show the energy changes during the reaction.

You are a chemist in a food processing plant tasked with producing a specific amount of citric acid from citrus fruits. The theoretical yield of citric acid from your batch of fruits is calculated to be 100 grams. After completing the extraction process, you weigh the actual amount of citric acid obtained and find that you produced 85 grams. What is the percent yield of citric acid for this extraction process?

• 75%
• 90%
• 85%
• 100%