Year 10 Science Chemical Reactions

Covalent Compound

A substance formed when atoms share pairs of electrons to create bonds, typically between non-metal atoms

Ionic Compound

A substance formed when positive ions (cations) and negative ions (anions) are held together by strong electrostatic forces, usually between metals and non-metals

Atom

The smallest unit of an element that has the properties of that element

Element

A pure substance made of only one kind of atom

Compound

A substance made up of atoms of two or more different elements joined by chemical bonds

Acid

A chemical substance which produces hydrogen ions in solutions, and reacts with bases to form ionic salt compounds

Base

Compounds that form hydroxyl ions (OH-) when dissolved in water, and reacts with acids to form salts

Indicator

Substances that change colour when they are added to acidic or alkaline solutions

pH scale

A scale from 0-14 where 0 is very acidic, 7 is neutral, and 14 is very basic

Valency

The number of electrons that each atom needs to gain, lose, or share to fill its outer shell

Chemical reaction

The process in which chemical bonds between atoms and ions break and reform, producing products that are different from the reactants

Law of conservation of mass/matter

In a chemical reaction, matter is neither created nor destroyed, nor is mass lost, but atoms are rearranged to form new chemicals

Reactants

The substances at the beginning of a reaction

Products

The substances that form as a result of a reaction

Endothermic reaction

Energy is absorbed from the environment, resulting in a drop in the surrounding temperature

Exothermic reaction

Energy is emitted into the environment, resulting in a rise in surrounding temperature

Naming chemical products

The metal is named first. The non-metal ends in -ide. Radicals end in -ate. For covalent compounds, mon, di, tri, tetra, and penta are used as prefixes.

Reactants: Acid and Metal

Products: Salt and Hydrogen

Reactants: Acid and Base

Products: Salt and Water

Reactants: Acid and Carbonate

Products: Salt and Water and Carbon Dioxide

Corrosion

A slow, exothermic reaction where metals (like iron) react with oxygen and moisture to form rust or tarnish.

Metal + Oxygen (+ sometimes water) → Metal oxide

Complete combustion

A quick, exothermic reaction of a substance with oxygen, producing heat and light.

Fuel + Oxygen → Carbon dioxide + Water

Incomplete combustion

A reaction with limited oxygen, producing toxic carbon monoxide. 

Fuel + Limited Oxygen → Carbon monoxide + Carbon + Water

Decomposition

Breaking down of a compound into simpler substances. Usually endothermic

Compound → Two or more simpler substances

Precipitation

A reaction in which two aqueous solutions react to form an insoluble solid and insoluble salt

Soluble salt A + Soluble salt B → Insoluble salt (precipitate) + Soluble salt

Aqueous

A solution where water is the solvent

Solubility

The ability of a substance to dissolve into a solvent

Solute

A substance dissolved into another substance

Solvent

A substance that dissolves another substance

Solution

A homogeneous mixture of one or more solutes dissolved in a solvent

Catalyst

A substance that speeds up a chemical reaction without being consumed or permanently changed in the process