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WorksheetsLimiting and Excess Reagents Challenge
Total questions: 15
Worksheet time: 8mins
What is a limiting reagent in a chemical reaction?
The limiting reagent is the reactant that is never used up.
The limiting reagent is the product formed in excess.
The limiting reagent is the reactant that is entirely used up first in a chemical reaction.
The limiting reagent is the catalyst that speeds up the reaction.
Given the reaction 2H2 + O2 -> 2H2O, identify the limiting reagent if you have 4 moles of H2 and 2 moles of O2.
O2
2H2O
O2 and H2
H2
How do you calculate the amount of excess reagent remaining after a reaction?
Remaining excess reagent = Initial moles of excess reagent + Moles of excess reagent that reacted
Remaining excess reagent = Initial moles of excess reagent - Moles of excess reagent that reacted
Remaining excess reagent = Moles of excess reagent that reacted
Remaining excess reagent = Initial moles of all reagents - Moles of product formed
In the reaction 3A + 2B -> 4C, if you start with 6 moles of A and 5 moles of B, which is the limiting reagent?
B
C
A and B
A
Calculate the theoretical yield of product C in the previous reaction if 4 moles of B are completely consumed.
4 moles of C
8 moles of C
2 moles of C
6 moles of C
What is the formula for calculating percent yield?
Percent Yield = (Theoretical Yield / Actual Yield) x 100
Percent Yield = (Actual Yield / Theoretical Yield) x 100
Percent Yield = (Actual Yield + Theoretical Yield) x 100
Percent Yield = (Actual Yield - Theoretical Yield) x 100
If the theoretical yield of a reaction is 10 grams and the actual yield is 8 grams, what is the percent yield?
70%
50%
90%
80%
In a reaction where 5 moles of X react with 3 moles of Y to produce 4 moles of Z, how many moles of Y are in excess if X is the limiting reagent?
1 mole of Y in excess
2 moles of Y in excess
3 moles of Y in excess
0 moles of Y in excess
How do you determine the stoichiometric coefficients in a balanced chemical equation?
Use the same number of molecules on both sides.
Ignore the coefficients and focus on the products.
Count only the reactants for balancing.
Adjust coefficients to balance the number of atoms of each element on both sides of the equation.
For the reaction 2Fe + 3Cl2 -> 2FeCl3, if you start with 2 moles of Fe and 4 moles of Cl2, how many moles of FeCl3 can be produced?
2 moles of FeCl3
1 mole of FeCl3
4 moles of FeCl3
3 moles of FeCl3
What is the excess amount of Cl2 after the reaction in the previous question?
Z moles of Cl2 used up
Y moles of Cl2 consumed
X moles of Cl2 remaining
A moles of Cl2 reacted
If 10 grams of reactant A produces 8 grams of product B, what is the percent yield if the theoretical yield is 12 grams?
100%
75%
66.67%
50%
Explain how to identify the limiting reagent using mole ratios.
The limiting reagent is always the reactant with the highest mass.
The limiting reagent can be identified by the color change during the reaction.
The limiting reagent is the one that is present in excess.
The limiting reagent is the reactant that produces the least amount of product based on mole ratios.
In a reaction where 1 mole of A reacts with 2 moles of B to produce 1 mole of C, if you have 3 moles of A and 5 moles of B, which reagent is limiting?
C
None
B
A
Calculate the excess amount of B remaining after the reaction in the previous question.
X grams
W grams
Z grams
Y grams
