ChemistryGrade 11Chemical Reactions and Stoichiometry

Reaction Lab: Stoichiometry and Limiting Reactants

Choose a balanced reaction, vary reactant amounts and yield efficiency, then identify the limiting reactant, leftover excess, and product mass.

Textbook unitChemical Reactions and StoichiometryGrade 11 Chemistry Unit 1

Keywordschemical reaction, stoichiometry, limiting reactant, mole, yieldMapped to available textbook headings

Practice modeManipulate, measure, explainUse the controls, then read the live evidence

Chemistry · Grade 10

Balance reactants and predict product yield

Choose a reaction, set starting moles, then use the balanced equation to identify the limiting reactant and expected product.

LimitingH2

Mole ratio: set equal moles of both reactants. Which is limiting? How do balanced equation coefficients determine this?

Limiting reagent: double reactant A, keep B constant. Does yield double? Identify the bottleneck and explain.

Theoretical yield: compute expected product mass for ammonia synthesis. Calculate percent yield and record.

2H2+1O2→2H2O

H24.00 mol

O22.20 mol

Product3.44 mol

Leftover H20.00 mol

Leftover O20.20 mol

Stoichiometry insight

H2 is limiting — runs out first, capping product at 3.440 mol (86% yield). Excess reactant is unused. Reaction: Hydrogen combustion.

Balanced ratio2:1:2

Reactant quotient2.00:2.20

Theoretical yield72.06 g

Actual yield61.97 g

Mass conversion79%

Find a setup with no leftover reactant, then reduce one reactant until it becomes limiting. Record both trials and compare product mass.

The limiting reactant is found by dividing available moles by the balanced coefficient. The smallest value controls product amount.

Mission

Use balanced coefficients to compare mole ratios and find the limiting reactant.
Calculate theoretical yield, actual yield, excess reactant, and product mass.
Explain how changing one reactant changes the final amount of product.