Chemicals & Chemical Change

Chemistry? Chemistry is the study of matter. Matter is anything that has mass and takes up space (volume). All matter is made up of tiny particles called atoms. (Atoms must have a mass and take up space.)

Classifying Matter

Pure Substance – A substance in which all of the particles are the same. –Element – Pure substance that is made of only one type of atom and it can’t be broken down into a simpler substance. –Compound – Pure substance that contains two or more different elements in a fixed ratio/proportion. Mixture – A substance that is made of two or more different types of particles. –Homogeneous mixture (AKA Solution) – A mixture that looks the same throughout – it has only one phase. –Heterogeneous mixture – A mixture that has a non-uniform composition. The different parts are easily identifiable and can usually be separated.

Properties of Matter Properties are characteristics that can be used to describe something. A physical property is a characteristic of a substance that can be described when the substance is by itself. –State, colour, hardness, odour, melting and boiling point are some physical properties. A chemical property is a characteristic behaviour that occurs when the substance is exposed to another substance. –Combustibility, reactivity with acids, corrosive and the ability to oxidize are chemical properties.

Chemical vs. Physical Change A physical change occurs when a substance undergoes a change in size or state. The substance does not change into another substance – it stays the same! H 2 O ( l )  H 2 O ( s ) A chemical change occurs when a substance undergoes a change and becomes a new substance with new properties. 2Na ( s ) + Cl 2 ( g )  2NaCl ( s )

Chemical Tests In your notes… –Indicate what a chemical test is used for in the lab. –Outline the chemical tests for oxygen, hydrogen, carbon dioxide and water.

Lab Safety Symbols Poison Flammable Explosive Corrosive Toxic Highly Reactive Oxidizing Agent Biohazard Radioactive

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