Chemistry Unit 4: Chemical Reactions

Rates of reactions, reversible reactions, equilibrium, Le Chatelier's principle, Haber/contact process, Oxidation/Reduction, Oxidation Numbers

Reversible reactions vs. irreversible reactions

(name the differences)

Reversible: have a forwards & backward reaction (where the reactants form products and products form the reactants). Reversible.

Irreversible: go in one way only, hard to reverse

Examples of irreversible reactions

Burning, boiling, combustion, rusting

Examples of reversible processes

Haber process, hydration and dehydration of copper(ii)sulfate and cobalt(ii)chloride

Rates of reactions

The ‘speed’ of the reaction: how fats or how slow it goes/how much product is produced per unit time

How can you increase the rate of reactions?

1) Increase temperature

2) Increase surface area

3) Increase concentration

4) Use a catalyst

Collision theory

The Collision Theory states that reactions occur when particles collide with each other successfully. The more the collisions, the more the successful collisions. You can increase the rate of a reaction by increasing temperature, for instance, as this would increase the KE of particles (leading to more successful collisions).

The hydration and dehydration of copper(II) sulfate colour changes

White —> Blue

The hydration and dehydration of cobalt(ii)chloride colour changes

Blue —> pink

A closed system is where ____

A closed system is where matter cannot enter or leave BUT energy can

Equilibrium

At equilibrium, the rate of the forward reaction is equal to the rate of the reverse reaction.

RULE about Equilibrium

The concentrations of the reactants and products are unchanging at equilibrium but are not necessarily the same!