Unit Exam Review

1. Unit Exam Review Lesson Objective: Students will have a clear expectation of how learning will be demonstrated on the unit exam.

2. 55 Multiple Choice Questions • 13 Questions on Chapter 1 • 13 Questions on Chapter 2 • 15 Questions on Chapter 3 • 14 Questions on Chapter 2

3. “Project Month” in January • Additional assessments requiring higher level thinking, and creativity/producing curricular content. • Aren’t you lucky?!

4. Review… • Class notes… do you remember why aluminum foam is used to create safer, lighter cars? What MRE’s are? How food is freeze dried? • Super quick review of lab safety symbols (one question) • Review the particle theory of matter (states of matter) and definitions of deposition and sublimation. • Review the difference between physical and chemical properties of matter- know the definitions and be able to give examples.

5. Physical Properties chart on page 99 in text: • Melting Point • Boiling Point • Hardness (Mohs’ Hardness Scale) • Malleability • Ductility • Crystal Shape • Solubility • Density • Conductivity

6. Chemical Properties of Matter (page 102) • How a substance reacts with other substances: • Reaction with acids • Ability to burn • Reaction with water • Behaviour in air • Reaction to heat • Evidence of a chemical change: chemical change always results in the formation of a different substance or substances. What evidence do you look for?

7. Colour • Odour • Formation of a gas.

8. Types of Pure Substances- made of only one type of matter and has a unique set of properties • Element- cannot be broken down into simpler substances. • Compounds- when two or more elements combing chemically.

9. 4 types of mixtures, and be able to describe them • Mechanical Mixture • Solution • Suspension • Colloid • You will be tested on the chart on page 103 in the text!

10. There are 7 questions on the timeline/history of chemistry. • No problem, because you have all completed your timeline!! • Review text pages 113-120.

11. 20 questions based directly on the periodic table • Review class notes online… • Period, group, alkali metals (group 1), alkaline-earth metals (group 2), halogens (group 17), noble gasses (group 18). • Differences between ionic and molecular compounds, and rules for naming them. • Definition of polyatomic ions • How to balance ionic equations.

12. Table, page 152

13. Chemical Reactions • Remember that chemical reactions take place when 2 or more substances combine to form new substances. • The materials at the start of a reaction are called reactants. • The new materials produced by the reaction are called the products.

14. Campfire Example • The burning wood undergoes a combustion reaction. • The reactants, or substances being combined in the reaction, are wood and oxygen. • The new materials being formed, or products, are carbon dioxide and water- they are formed while energy is released.

15. A Chemical Reaction can be written as a Word Equation: • Wood + Oxygen Carbon dioxide + water + energy released. • Plus signs separate the reactants from each other and the products from each other. The arrow indicates the direction in which the reaction is most likely to occur. • Reactions can occur in either direction.

16. Remember that sometimes testing in the lab may be needed to prove a chemical reaction has occurred. • For example, the formation of bubbles in a solution doesn’t always mean that a new gas is being produced in a chemical reaction… could just be evidence of boiling. • Evidence of heat being released or absorbed may also indicate a physical change rather than a chemical change. • Some solids, for example, release heat when they are dissolved.

17. Evidence of a chemical reaction may include one or more of these: • A colour change • The formation of an odour • The formation of a solid or a gas • The release or absorption of heat

18. Endothermic VS Exothermic Reactions • Exothermic reaction: a chemical reaction that releases heat energy. E.g. When you burn an object in the presence of oxygen, or when your body metabolizes food. • Endothermic reaction: a chemical reaction that absorbs heat energy. E.g. Chemical cold packs in first aid kids, or when the temperature drops just after the reaction of baking soda and vinegar. • Endothermic and exothermic reactions involve the forming or breaking of chemical bonds.

19. Chemical Changes Involving Oxygen • Among the most common types of chemical reactions. • Three examples: • Combustion- E.g. Fire. Combustion could be considered the first chemical reaction used by humans. Combustion occurs when oxygen reacts with a substance to form a new substance and give off energy.

20. Corrosion • Corrosion is the slow chemical change that occurs when oxygen reacts with a metal. • E.g. Rusting occurs when iron reacts with oxygen to form iron oxide. • Cellular respiration: is a chemical reaction that takes place in the cells of your body. Food (glucose) reacts with oxygen to produce energy, water, and carbon dioxide.

21. Conservation of Matter • In a chemical reaction, products are formed when the reactant(s) undergo a change. The products usually look very different than the reactants. • The total mass of these products, however, is always the same as the total mass of the reactants. • This law is called the conservation of matter.

22. Matter is neither created or destroyed in a chemical reaction. • Experiments have been done in closed systems where no additional material is allowed to enter or to leave. • The result? No exceptions to this law have ever been found in any chemical reaction.

23. Open Systems • Sometimes the products of a chemical reaction can escape into the air… when Alka-Seltzer is dissolved in water, the products left in a beaker will not be the same as the mass in the beginning of the experiment. • Carbon dioxide gas will be given off into the air- this is an example of an open system. If the carbon dioxide is “trapped” the mass would be the same. • In a nuclear reaction, some of the mass is converted to energy, as Albert Einstein expressed as his famous E=mc2

24. Factors Affecting the Rate of a Chemical Reaction: • If you’ve ever coloured your hair and ended up with a burned scalp, or odd colour… Or baked a cake and ended up with batter that rose too high, or not enough… You have realized that certain factors can affect the rate of a chemical reaction: • 1. The presence of a catalyst • 2. The concentration of the reactants • 3. The temperature of the reactants • 4. The surface area of the reactants

25. Catalysts • Are substances that help a reaction proceed faster. • They are present with the reactants, but are not consumed (used up) during a reaction. • Chemical reactions involving catalysts can be found in living and non-living things. • Many reactions, such as the breakdown of food, require a catalyst called an enzyme.

26. Without enzymes, may reactions would require higher temperatures… Which would be deadly to the human body. • Enzymes can help get rid of poisons in the body quickly. • An enzyme called catalase, which is found in many types of animal and plant cells, speeds up the breakdown of hydrogen peroxide into harmless oxygen and water.

27. Concentration: • The greater the concentration of the reactants, the faster the reaction. • The increased concentration of the reactants means that there are more atoms of each reactant available to react.

28. Temperature • The more heat added to the reactants, the faster the reaction. • The added heat causes the atoms of each reactant to move faster.

29. Surface area • Increasing the surface area of the reaction is another factor that can increase the rate of a reaction. • The greater surface area of the reactants means that more area is available for reaction.