Presentation on theme: "Chemicals & Chemical Change. Chemistry? Chemistry is the study of matter. Matter is anything that has mass and takes up space (volume). All matter is."— Presentation transcript:
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.)
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.