Types of reactions

• combustion: a chemical reaction that occurs when a fuel is burned in oxygen
• decomposition: the breaking down of a compound into simpler substances, usually by heat or light.
• reversible reactions: a reaction that can be reversed by the same process that caused it to happen
• irreversible reactions: a reaction that cannot be reversed by the same process that caused it to happen
• neutralisation: a type of exothermic reaction where an acid reacts with an alkali to form salt and water
• lime: a white caustic alkaline substance consisting of calcium oxide, which is obtained by heating limestone and which combines with water with the production of much heat; quicklime.
• solid calcium hydroxide(slaked lime): white solid, insoluble in water, melts at 100 degrees
• calcium oxide is made from the thermal decomposition of marble
• displacement reactions: when a reactive metal reacts with a compound of a less reactive metal the metals swap places - and the less metal is produced
• law of conservation of mass: mass of the product is equal to the mass of the reactants
• How does the mass change when a reactant or product is a gas?

  If a gas escapes, the total mass will look as if it has decreased. If a gas is gained, the total mass will look as if it has increased. However, the total mass stays the same if the mass of the gas is included.