1. Science 9 Unit 2 Chemistry

2. Properties of Matter Matter is anything that has mass and occupies space. Matter can be identified by its physical properties (melting point, density, colour and state) Matter can also be identified by its chemical properties (how a substance reacts with others. Ways to Describe or classify matter: –State (solid, liquid or gas) –Solubility (do they mix well) –Luster ( are they dull or shiny) –Density

3. Lesson 921 Matter Mixture Solution/ Homogeneous Mixture eg. Apple juice Appear as one usually clear Mechanical Mixture Heterogeneous e.g sand and gravel Ordinary Mech. Mixture Lg parts can see them Stay mixed Suspensions Lg.particles evenly Mixed but settle Colloids Liquid in liquid Milk, mayo, jelly Emulsions Quickly separate to form layers Pure Substance Element One Atom E.g.. Oxygen Compounds Two or more atoms E.g.. Water

4. Types of Matter Pure Substance –Material that contains one kind of particle –Either an element or compound Mixture –Combination of two or more pure substances such that each one’s properties are not lost but may be hidden

5. Types of Mixtures Homogeneous mixture (solution) –Particles are uniformly scattered; has a uniform composition –Usually clear and cannot be separated by filtering –Eg. Apple juice Heterogeneous mixture (mechanical) –Particles are not uniformly scattered and not a uniform composition. –Can see the parts –Can be filtered and separated

6. 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

7. Changes in Matter Physical Change Chemical Change Change in form/ change from solid, liquid or gas Always reversible! The composition doesn’t change Water is water even if frozen or condensed 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. change (heat absorbed or produced) Irreversible Form a precipitate (solid) Starting material used up A new material formed

8. Chemical Reactions & Law of Conservation of Mass Substances that go into a chemical reaction are the reactants and the products 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

9. Types of Chemical Reactions 2 Types of Chemical Reactions Endothermic – where energy is absorbed eg. Alkaseltzer and water Exothermic- where energy is released e.g. an explosion or fire eg. Burning log Oxidation reactions are common in nature –Some reactions are slow; others are fast –Eg. Corrosion -Corrosion is the oxidation of metals or rocks in the presence of air and moisture This is an endothermic reaction. E.g. Iron + O 2  rust –Combustion- Combustion is an exothermic combination of a substance with oxygen. This requires heat, oxygen and fuel e.g. a barbeque Chemical reactions are represented by word or symbol equations –Eg. Magnesium + Hydrochloric Acid  Magnesium chloride & Hydrogen gas –E.g. Mg + 2HCl  MgCl 2 + H 2 (g)

10. 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

11. Atomic Structure Dalton’s Atomic Theory- review from text –Matter is made of atoms –Atoms can’t be created or destroyed –All atoms of the same element are the same size and weight. Atoms are composed of subatomic particles –Protons, electrons and neutrons –Each of which have their own characteristics.

12. Subatomic Particles Protons –Have + charge –Large size –Found in the nucleus of an atom Electrons –Have negative (-) charge –Small (very sm. Compared t the proton) –Found in the orbit or energy level of the atom Neutrons –Have no charge –Large in size (same size as proton) –Found in the nucleus of an atom

13. Atomic Number The atomic number of an atom is the number of protons found in the nucleus and also represents the no. of electrons found in the orbits The Atomic Mass Unit is the total mass of the protons and neutrons in the nucleus

14. Periodic Table review Elements are grouped based on physical and chemical properties (melting point, color, density, state and reactivity) Metals on left side Non-metals on right side Metalloids on “staircase” Noble gases on extreme right side (unreactive, and stable) Horizontal rows called periods –All atoms in a period have the same no. of energy levels Vertical columns called groups or families –All atoms in a group have the same chemical characteristics Each box on the table contains specific info. About each element (pg.440- 441 in text) –Atomic number –Ions –Symbol –Name –Atomic mass unit

15. Quiz Info Memorize the symbols and names of all elements from 1-30. Also, include iron, copper, zinc, silver,tin,lead,mercury and gold Quiz will include everything else we covered today.