1. Lecture 63 – Lecture 64 Limiting Reactants Ozgur Unal
NIS – CHEMISTRY
Lecture 63 – Lecture 64
Limiting Reactants
Ozgur Unal

2. Limiting Reactants
A soccer team can be formed from 1 goal keeper, 3 defense, 5 midfield and 2 offense players.
A school has:
4 goalkeepers
13 defense players
22 midfield players
6 offense players
How many football teams can be formed in this school?

3. Limiting Reactants Limiting players  Offense players
Excess players  1 goalkeeper, 4 defense players, 7 midfield players
In a chemical reaction, the limiting reactant limits the extent of the reaction and, thereby, determines the amount of product formed.
A portion of all the other reactants remains after the reaction stops  Reactants leftover when a reaction stops are excess reactants.
Consider the following chemical reaction:
S8 (l) + Cl2 (g)  4S2Cl2 (l)

4. Limiting Reactants
If 200 g of sulfur reacts with 100 g of chlorine, what mass of disulfur dichloride is produced?
Moles of Cl2 before the reaction = mol Cl2
Moles of S8 before the reaction = mol S8
Limiting reactant: Cl2
Excess reactant: S8
Amount of S2Cl2 formed = g
Moles of S8 reacted = mol S8
Mass of S8 reacted = g S8
Amount of S8 remaining = g

5. Limiting Reactants
Example: A tetraphosphorus trisulphide (P4S3) is used in the match heads of some matches. It is produced in the reaction 8P4 + 3S8  8P4S3. Determine which of the following statements are incorrect, and rewrite the incorrect statements to make them correct.
4 mol P4 reacts with 1.5 mol S8 to form 4 mol P4S3.
Sulfur is the limiting reactant when 4 mol P4 and 4 mol S8 react.
6 mol P4 reacts with 6 mol S8, forming 1320 g P4S3.