Science 9 Exam Review Matter Unit

What is Matter? Matter is anything that has MASS and VOLUME Mass: the amount of matter in an object and is measured in grams (g) – different from weight Volume: the space an object occupies (Eg: mL & cm3)

Physical vs. Chemical Properties Physical Properties Chemical Properties Hardness Reaction with acid State (Solid, Liquid, Gas) Combustibility Malleability Ductility Density (D = m/V) Melting Point/ Boiling Point Solubility Crystal Form Viscosity

What is a chemical change? Give an example. Chemical changes are those that have the substance becoming something completely different and it can’t be returned to the starting state. When the candle is burning and some of the wax changes into carbon dioxide and gives off energy, that is a chemical change. The wax won’t return and the energy is used up (heat & light).

What is a Physical Change? Give an example. Physical changes usually can be identified by seeing that the state or form have changed but the substance itself is still the same. Examples would include: water melting, water freezing, water evaporating, water condensing, cutting something into pieces, dissolving sugar in water Can you think of any?

What is Corrosion? The chemical reaction which occurs between a metal and oxygen which results in the formation of a new substance called an oxide. There are both positive and negative forms of corrosion.

What is Negative Corrosion? commonly known as RUSTING Iron and steel react with oxygen and forms rust. Rust eats away at the metal and then reacts like a sponge, sucking up water and other pollutants until a hole is formed in the metal.

What is Positive Corrosion? Aluminum undergoes positive corrosion such as when your baking pans at home develop the gray coating on the metal. The gray coating is actually aluminum oxide, or corrosion, which protects the metal.

What is Combustion? Combustion is the reaction of one substance with the oxygen around it. Once this reaction occurs heat and light are produced. There are 3 necessary components of combustion: oxygen, fuel and heat. See page 39 and draw the fire triangle

What is the Particle Theory of Matter? All matter is made up of tiny particles. All particles of one substance are the same. Different substances are made of different particles. The particles are always moving. The more energy the particles have, the faster they move. There are attractive forces between the particles. These forces are stronger when the particles are closer together.

Pure Substances and Mixtures There are two categories of substances: pure substances Mixtures (heterogeneous and homogeneous)

Elements and Compounds Elements are pure substances that cannot be broken down into simpler substances. Elements are the building blocks of matter!!! Compounds are pure substances that contain two or more different elements in a fixed proportion. Example: water is H2O.

Atoms & Molecules Scientists now call the particles in the particle theory atoms. Each element is made of only one kind of atom. Atoms join together in combinations. When two or more atoms join together, a molecule is formed. Molecules can contain two atoms or thousands of atoms. Water molecules have 2 hydrogen atoms and 1 oxygen atom

Chemical Symbols and Formulas Single symbols are used to represent elements. Combinations of symbols are used to represent compounds. These combinations are called chemical formulas. The chemical formula indicates which elements are present and in what ratio.

What are the 3 types of subatomic particles? Protons Neutrons Electrons Where is each found? Charge? Mass? Use periodic table to determine for various elements.

Complete the chart Element Symbol Mass # Atomic # # protons # electron # neutron Calcium 27 Ar 15 39

Rutherford & Bohr Rutherford – gold foil experiment to determine nucleus exists Nuclear model of the atom Bohr – suggested electrons orbit around the nucleus Planetary model of the atom

Bohr Diagrams Try phosphorus

Bohr Rutherford Diagrams Try sodium

Counting atoms Try: CaCl2 Ba(NO3)2 2NaOH

Periodic Table Groups/Families Periods Metals Non-metals

Locate the following on your periodic table: Group of One Noble gases Alkali Metals Halogens Metalloids