Limiting Reactants Flashcards
(12 cards)
Q: What is a limiting reactant?
A: The reactant that is completely consumed in a chemical reaction, limiting the amount of product formed.
Q: What is an excess reactant?
A: The reactant that remains after the limiting reactant is used up; it does not limit the reaction.
Q: What happens when the limiting reactant is used up?
A: The reaction stops and no more products can be formed.
Q: Does the limiting reactant always have the smallest mass?
A: No. It depends on the mole ratio, not mass.
Q: What are the steps to identify the limiting reactant?
Write a balanced chemical equation.
Convert masses of reactants to moles.
Use mole ratios to determine which reactant would be used up first.
That reactant is the limiting one.
Q: After finding the limiting reactant, how do you calculate the mass of product formed?
Use mole ratio to convert moles of limiting reactant to moles of product.
Convert moles of product to mass using molar mass.
Q: What is theoretical yield?
A: The maximum amount of product that could form from a reaction if everything goes perfectly.
Q: What is experimental (actual) yield?
A: The amount of product actually collected during an experiment.
Q: What causes the experimental yield to be lower than the theoretical yield?
Side reactions
Loss during transfer
Incomplete reactions
Measurement error
Q: What is the formula for percentage yield?
(Experimental yield / Theoretical yield) x 100
Q: What if the experimental yield is greater than the theoretical yield?
A: Likely a measurement error or product contamination.
Q: What are the steps to calculate percentage yield?
Calculate theoretical yield from the balanced equation.
Use the percentage yield formula.
Show all working with correct units.
