Effect of catalyst on the rate of reactionWhat is catalyst ?A catalyst is a substance which alters the rate of chemical reaction while it remains chemically unchanged at the end of the reaction

Types of catalyst2 Types :a) Positive catalyst : Increase the rate of reactionb) Negative catalyst : lower the rate of reaction

Special characteristics of catalystIt alters the rate of chemical reaction,The amount of product remains unchanged with or without catalyst,It remains chemically unchanged during the reaction( the mass and chemical composition of the catalyst remain the same )It is specific in its action ( only catalyse a particular reaction )

Special characteristics of catalystOnly a small amount of catalyst is needed to change in the rate of reaction but increasing the amount will increase the rate,Powdered catalyst is more effective than lump catalyst,Catalyst may undergo physical changes ( crystal powder ) Most catalyst are transition elements or compound of transition element

Effect of pressure on the rate of reactionThe reaction involves gaseous reactantsHigh rate at a higher pressure

Application of the factors affecting the rate of reaction in daily lifeBurning smaller pieces of charcoal,Storing of food in a refrigerator,Cooking of food in a pressure cookerCooking of solid food in small size

Application of the factors affecting the rate of reaction in industrial processesChoosing optimum conditions to achieveShorter time of production,Higher yieldLower cost of production Costly at high temperature and high pressure , catalyst are used to increase the rate of reaction.

The use of catalyst Enables the processes to be run in a shorter time, at an optimum temperature and pressure,The cost of production is lower.

ExamplesHaber process - Manufacture ammonia N2 + 3H2 2NH3 - Mixture of nitrogen gas and hydrogen gas in the ratio 1 : 3 - Condition : Catalyst : Iron powder Temperature : 4500C-5500C Pressure : 200-300 atm