6. Chemical Reactions

Physical Changes A physical change is a change in which no new substance is formed - only the physical appearance or state changes. No new substances are formed…

What is Rate of Reaction? The rate of reaction is how quickly reactants are converted into products. rate of reaction = amount of reactant used (or product…

What is Collision Theory? Collision theory explains reaction rates at a particle level. For a reaction to happen, particles must: Collide with each other…

Explaining Each Factor Using Collision Theory Exam answers should explain the effect of a factor in terms of collisions: state what happens to the particles,…

Method 1: Change in Mass Used when a gas escapes from the reaction flask. The flask sits on a balance, and mass is recorded at regular time intervals - mass…

Reading a Rate of Reaction Graph A typical rate graph plots the amount of product formed (e.g. volume of gas, cm³) on the y-axis against time on the x-axis.…

What is a Reversible Reaction? A reversible reaction is one where the products can react together to reform the original reactants - the reaction can go in both…

Dynamic Equilibrium A reversible reaction in a closed system reaches equilibrium when: the rate of the forward reaction equals the rate of the reverse reaction,…

The Haber Process The Haber Process is the industrial, reversible synthesis of ammonia, mainly for fertiliser production. N₂(g) + 3H₂(g) ⇌ 2NH₃(g) ΔH = −92…

The Contact Process The Contact Process manufactures sulfuric acid (H₂SO₄). Its key reversible step converts sulfur dioxide to sulfur trioxide: 2SO₂(g) + O₂(g)…

What is a Redox Reaction? A redox reaction is a reaction involving oxidation and reduction happening simultaneously - the term combines "reduction" and…

Oxidation and Reduction in Terms of Electrons Oxidation is the loss of electrons Reduction is the gain of electrons OIL RIG: Oxidation Is Loss, Reduction Is…