Which reactant runs out first?
"Which reactant runs out first?" is a free, interactive Class 11 Chemistry simulation for NEET and JEE, built on the lesson "Stoichiometry and the limiting reagent" in Some Basic Concepts of Chemistry. It is an interactive picture of stoichiometry and the limiting reagent. Divide each reactant's moles by its coefficient in the balanced equation; the smallest quotient marks the limiting reagent, and it alone fixes how much product forms. Having fewer moles does not make a reactant limiting. JEE Main asked 45 questions from this chapter across the 42 shifts Lumi has analysed (2017–2026).
From the lesson Stoichiometry and the limiting reagent in Some Basic Concepts of Chemistry. Change the values and watch what happens.
In JEE Main
42 shifts analysed
45 questions from Some Basic Concepts of Chemistry across the 42 JEE Main shifts Lumi has analysed (2017–2026).
The idea behind it
NCERT § "Stoichiometry and Stoichiometric Calculations"
- Stoichiometry is the calculation of the masses and, for gases, volumes of reactants and products from a balanced equation.
- The coefficients in a balanced equation give mole ratios (and, for gases at the same temperature and pressure, volume ratios), not mass ratios.
- Balancing an equation means making the count of every element match on the left and right sides; this is conservation of mass written in symbols.
- The limiting reagent is the reactant that is used up first; it alone decides how much product forms, and the other reactant is left in excess.
- To find it, divide the available moles of each reactant by its coefficient; the smallest quotient marks the limiting reagent.
- When a sample is impure, first find the mass of the pure reacting substance from its percentage purity, then do the mole calculation.
Questions
3 answers
- What does the "Which reactant runs out first?" simulation show?
- It is an interactive picture of stoichiometry and the limiting reagent.
- Does JEE Main ask questions from Some Basic Concepts of Chemistry?
- Yes. JEE Main asked 45 questions from this chapter across the 42 shifts Lumi has analysed (2017–2026).
- Is this simulation free?
- Yes. It is free and runs in the browser on a phone or a laptop. It belongs to the lesson "Stoichiometry and the limiting reagent" in Some Basic Concepts of Chemistry (Class 11 Chemistry).
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