Define (i) rate of reaction, (ii) catalyst - Leaving Cert Chemistry - Question 9 - 2013

A catalyst is a substance that alters the speed of a reaction without being chemically changed at the end of the reaction.

Manganese(IV) oxide (MnO₂) is commonly used as a catalyst in the breakdown of hydrogen peroxide (H₂O₂) to produce oxygen (O₂).

The term used for catalysts produced by living cells is 'enzymes.' An example of an enzyme is catalase, which facilitates the conversion of hydrogen peroxide into water and oxygen.

The rate of oxygen production in flask B, which contains powdered catalyst, would be expected to be faster than in flask A, which contains the solid block of catalyst. This is due to the larger surface area available for reaction in the powdered form.

An increase in temperature is expected to increase the rate of the reaction in flask A. As temperature rises, the kinetic energy of the particles increases, leading to more frequent and effective collisions between the catalyst and hydrogen peroxide.

Two common catalysts found in catalytic converters are platinum and palladium.

The use of a catalytic converter benefits the environment by converting harmful gases, such as carbon monoxide and nitrogen oxides, into less harmful substances, such as carbon dioxide and nitrogen, thus reducing air pollution.