Topic 6 Chemical Reactions

Rate of reaction

Change in amount of reactant or product per unit time

Collision theory

Particles must collide with enough energy and correct orientation

Effect of temperature on rate

Higher temperature increases frequency and energy of collisions

Effect of concentration on rate

Higher concentration increases collision frequency

Effect of surface area on rate

Larger surface area increases collision frequency

Effect of catalyst on rate

Lowers activation energy

Reversible reaction

Reaction that can proceed in both directions

Dynamic equilibrium

Forward and reverse reactions occur at equal rates

Conditions for equilibrium

Closed system constant temperature

Le Chatelier principle

Equilibrium shifts to oppose change

Effect of increasing temperature on exothermic equilibrium

Shifts left

Effect of increasing pressure on equilibrium

Favours side with fewer gas molecules

Redox reaction

Reaction involving electron transfer

Oxidising agent

Substance that gains electrons

Reducing agent

Substance that loses electrons

Precipitation reaction

Reaction producing insoluble solid

Neutralisation reaction

Acid reacts with base to form salt and water

Thermal decomposition

Breakdown by heat

Electrolytic decomposition

Breakdown using electricity