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

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?

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)

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 = 1.410 mol Cl2 Moles of S8 before the reaction = 0.7797 mol S8 Limiting reactant: Cl2 Excess reactant: S8 Amount of S2Cl2 formed = 190.4 g Moles of S8 reacted = 0.3525 mol S8 Mass of S8 reacted = 90.42 g S8 Amount of S8 remaining = 109.6 g

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.