Stoichiometry and Limiting Reagent
A balanced equation fixes the mole ratio of reactants and products, and the limiting reagent is the one that is consumed first.
What is Stoichiometry and Limiting Reagent?
A balanced equation fixes the mole ratio of reactants and products, and the limiting reagent is the one that is consumed first.
Key formula / rule: Balance the equation before any ratio is used.
Key points
- Compute the limiting reagent for a given set of reactant amounts.
- Apply stoichiometry to determine theoretical and percentage yield.
Common exam trap
Choosing the reagent with the smaller mass as limiting.
Definitions
- Term
Stoichiometry and Limiting Reagent
- Meaning
A balanced equation fixes the mole ratio of reactants and products, and the limiting reagent is the one that is consumed first.
- Term
Stoichiometry and Limiting Reagent — explanation
- Meaning
Comparing available moles against the required ratio identifies which reactant runs out. Yield is then computed from that reagent alone, with the excess reagent left over.
Learning objectives
Compute the limiting reagent for a given set of reactant amounts.
Apply stoichiometry to determine theoretical and percentage yield.
Formulae
- Key point
Balance the equation before any ratio is used.
- Key point
Divide available moles by stoichiometric coefficients to find the limiting reagent.
- Key point
Percentage yield is actual divided by theoretical yield × 100.
Prerequisites
CHE-U1-BC-T1-S1-C1
Common mistakes
Choosing the reagent with the smaller mass as limiting.
Computing yield from the excess reagent.
Keywords
Stoichiometry
Limiting
Reagent
Practice preview
In the reaction 2H2(g) + O2(g) -> 2H2O(l), if 4 moles of H2 and 3 moles of O2 are mixed and allowed to react, which reactant is the limiting reagent?…
easy
Which of the following statements correctly defines a limiting reagent in a chemical reaction?…
easy
Methane (CH4) burns in oxygen according to the equation: CH4(g) + 2O2(g) -> CO2(g) + 2H2O(g). If 10 L of CH4 reacts with 30 L of O2 at the same temperature and pressure, what is the total volume of gaseous products forme…
medium