Science 9 Unit 2 Chemistry

Particle Theory of Matter Matter is made up of tiny particles Each pure substance has its own kind of particle. Particles attract each other Particles are always moving Particle move faster when heated

Properties of Matter State (solid, liquid or gas) Solubility (do they mix well) Luster ( are they dull or shiny) Density

Lesson 921 Matter Mixture Solution/ Homogeneous mixture Mechanical Mixture Heterogeneous Ordinary Mech. Mixture SuspensionsColloids Emulsions Pure Substance Element One Atom E.g.. Oxygen Compounds Two or more atoms E.g.. Water

Types of Matter Matter is a solid, liquid or gas There are mixtures and pure substances A pure substance is an element-one atom (eg.O 2) or a compound-two or more atoms together (eg.H 2 O) A mixture is either Homogeneous (solution) or Heterogeneous (mechanical) Homogeneous mixtures (solutions) appear as one and are usually clear e.g.. Pure Apple juice Heterogeneous mixtures (mechanical mixtures) have parts that you can see. E.g.. Iced tea or Kool Aid

Heterogeneous Mixtures Heterogeneous mixtures is a mechanical mixture where you can see the parts There are three types of heterogeneous mixtures based on the size of the particles. Ordinary mechanical mixtures have parts big enough to see and they stay mixed. E.g. granite Suspensions are large mixed particles but separate if left or by filtering. E.g. liquid medications Colloids are fine particles evenly distributed through a second substance. E.g. hair gel and clouds. Emulsions are a type of colloid that are liquids in liquids. E.g. Milk, Mayonnaise, Jell-O

Changes in Matter Physical Change Chemical Change Change in form/ change from solid, liquid or gas Always reversible! E.G. Ice changing to water (melting) One kind of matter is changed to a different kind of matter E.G. Iron changing to rust with the addition of oxygen. Identifiers: Color change Gas bubbles Temp. increase Irreversible Form a precipitate (solid)

Chemical Reactions Substances that go into a chemical reaction are the reactants and the products 2 Types of Chemical Reactions Endothermic – where energy is absorbed Exothermic- where energy is released e.g. an explosion or fire

Types of Chemical Reactions Corrosion is the oxidation of metals or rocks in the presence of air and moisture E.g. Iron + O 2  rust Combustion is an exothermic combination of a substance with oxygen. This requires heat, oxygen and fuel e.g. a barbeque Neutralization is when an acid and a base are added together.

Conservation of Reaction During a chemical reaction the reactants are used up During a chemical reaction the products are created or produced Law of conservation of mass states that in a chemical change the total mass of the new substance is the same as the total mass of the original. Mass of reactants = Mass of products Therefore 2H 2 + O 2  H 2 O

Factors Affecting The Rate of Chemical Reactions Heat – the more heat added the faster the reaction. E.g. burning dinner Concentration – the higher the concentration of reactants the faster the reaction Surface area – the more surface area the faster the reaction. E.g. a sugar cube takes longer to dissolve than regular refined sugar Energy – the type of energy used will determine how fast the reaction occurs. E.g. if you use electrical energy from a battery the reaction will be faster