Chemical Changes

Physical change

No new substance form. Involves a change in physical properties

Chemical change

New substance formed

Element

any of the basic substances on the periodic table, such as oxygen (O2), iron (Fe) and gold (Au). They are made up of only one type of atom

Compounds

made up of two or more different types of atoms bonded together, such as carbon dioxide (CO2) and sodium chloride (NaCl). The chemical formula of a compound shows the relative number of atoms of each element.

Reactants

The substances that react with each other

Products

The new substances formed by a reaction

Coefficient

multiplies the entire chemical formula

Subscripts

The number of atoms

Solution

A mixture formed when one substance is dissolved in another

React

To undergo a chemical change

Corrosive

Able to break down or destroy substance by reacting with them

Sour

Having a sharp, tangy or unpleasant taste or smell

Soluble

Able to be dissolved, especially in water

Caustic

Able to burn or corrode organic tissue by chemical action

Alkali

A base in solution or one that can dissolve

Acid

A substance that releases H+ ions in a solution

Base

A substance that release OH- ions in a solution

Hydrogen ion

A positive ion formed when a hydrogen atom loses it one electron, with symbol H+

Hydroxide ion

A negative ion formed when a oxygen atom bonds with a hydrogen atom, with symbol OH-

Neutralisation

A chemical reaction where an acid and a base react to produce water and salt

Collision theory

The idea that this re-arrangement requires collisions between the reactant particles. It's only when the particles are in contact that new bonds can form to make the products.