1. Matter & Chemical Change
Review

2. Reactants:
In a chemical reaction, the starting materials, which are called reactants, react to create new materials called products.

4. Or equations can be written in symbol equations:

5. Law of Conservation of Mass
States that the mass of the reactants equals the mass of the products.

6. Law of Conservation of Mass
States that the mass is neither created or destroyed… It is only changed.

7. Closed Systems:
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.

8. 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

9. State: melting, freezing, boiling, or condensing
Physical changes can be made by altering the following properties of matter:
State: melting, freezing, boiling, or condensing
Shape: cutting, breaking, or crushing
Colour: dying or painting.

10. A physical change does not change the substance into another material.

12. A chemical change is a change in matter that produces 1 or more new substances.
The new substance(s) has properties that are different than the starting materials.
Fire is created when oxygen and wood react in the presence of heat. Ash and smoke are new substances that are created when wood is burned. A chemical change cannot be reversed. You cannot take ash from a fire and turn in it back into wood.

13. Evidence of chemical change?
A gas is produced
A substance disappears
A solid is formed
Heat is given off
A smell is produced

14. Good example of chemical change:
Take a table of baking soda and mix it into a cup of vinegar.
You will see a lot of bubbles and foam forming.
These bubbles and foam are evidence of a chemical reaction. The gas that is produced in the bubbles and foam is called carbon dioxide.

15. Chemical Reactions
The reaction of magnesium and hydrochloric acid can be written in the following 2 ways:

16. Word Equation:
Magnesium reacts with hydrochloric acid to produce magnesium chloride and hydrogen gas.

17. Symbol Equation Mg(S) + 2HCl(aq) MgCl2(aq) + H2(g) Reactants Products
Balanced equation shows the law of conservation of matter is true. Total number of atoms on reactants side equals total number of atoms on product side.

18. Classifying Chemical Reactions:
1 way is by whether or not they release or absorb heat.
Exothermic: releases heat
Endothermic: absorbs heat.

19. Chemical Reactions: Chemical reaction Releases heat Exothermic
Burning log
Chemical reaction Absorbs heat Endothermic
Alka-Seltzer/water

20. Different reactions occur at different rates.
Some oxidation reactions (which involve oxygen) and are common in nature, are very rapid while others are very slow.
When fuel is burned in a car, the reaction happens very quickly to produce carbon dioxide and water vapour.
A much slower oxidation reaction is rusting, which is an example of corrosion.

21. Page 160, Chemical Changes Involving Oxygen
Read…
Page 160, Chemical Changes Involving Oxygen

23. Oxidization Reactions
Corrosion Combustion Respiration

24. The rate of a chemical reaction can be increased or decreased by:
Introducing a catalyst:
Catalysts are substances that help a reaction proceed faster.

25. Chemical reactions involving catalysts can be found in both living and non-living things.
The most common example in living things is in your body. Many reactions, such as the breaking down of food, require a catalyst called an enzyme. Without enzymes, many reactions would require much higher temperatures—a situation that would be deadly to the human body.

26. Enzymes can help get rid of poisons in the body quickly.
For example, one product of reactions in cells is hydrogen peroxide (H2O2). Hydrogen peroxide is poisonous. An enzyme called catalase, which is found in many different 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.

30. Matter Anything that has mass and occupies space.
Can be identified by its physical and chemical properties.

31. Physical Properties Easily observable
Include characteristics such as melting point, density, colour, and state.
Review chart on page 99. Remember what Mohs’ hardness scale is.

32. Chemical Properties
Refer to how the substance reacts with other substances.
See the difference? Iron is a reddish solid (physical properties) that reacts with oxygen to form rust (chemical property).

33. Classifying Matter

34. 2 kinds of pure substances
Elements and compounds
Elements: only one kind of atom
Compounds: 2 or more elements chemically combined.
*compounds can only be separated by chemical reaction.

35. Heterogeneous and homogeneous
2 kinds of mixtures
Heterogeneous and homogeneous
*solutions are the best mixed mixtures

36. Pure Substances
Cannot be broken down into a simpler substance by physical means.
A mixture can- for example, through filtration

37. One common method is by separating it into metals and non-metals.
Classifying Matter
One common method is by separating it into metals and non-metals.

38. Metals:
Generally shiny, malleable, ductile, and electrical conductors.
Iron, copper, and aluminum.

39. Non-Metals:
Generally dull, brittle and do not conduct electricity.
Oxygen, phosphorus, and sulfur.

40. Scientific Theory
Set of ideas that help to explain certain facts. Not a guess; it has been tested and is supported by results of experiments.
Uses information available at the time.
Theories can be disproved as new information becomes available or as technology improves.

41. Originated with the ancient Greeks and continues to develop today.
Atomic Theory
Originated with the ancient Greeks and continues to develop today.

42. General Timeline
400 BC Democritus used word atomos to describe the smallest particle of matter that could not be broken down any further.
Atomos means indivisible.

43. General Timeline 1660s, Robert Boyle studies particles of gases.
He believed all matter was made up of tiny particles; particles combined to make different substances.

44. General Timeline
1808, John Dalton suggests that all matter is made up of elements.
Thought elements were pure substances made up of particles called atoms.
Thought atoms were tiny, solid spheres of matter.

45. General Timeline 1859, J. Plucker built cathode ray tube.
Used by others to study gas molecules in more detail.

46. For the rest of the general timeline, read your text!!
Pages
Other names you should know/their contributions: J.J. Thompson, Hantaro Nagaoka (Saturn model, 1904), Ernest Rutherford, Niels Bohr & his model, Erwin Schrodinger.

47. Atomic structure and the properties of elements.

49. Atomic Number:
The number of protons found in the nucleus.

50. Atomic Number Also tells you how many electrons found in the orbits.
Elements in the periodic table are arranged in order of increasing atomic number.

51. Atomic Mass Unit (amu):
The total mass of the protons and neutrons in the nucleus.

52. Periods
Horizontal rows

53. Know Group 1, 2, 17 & 18 – names, properties, combine with?
Family/Group
Vertical Columns
Know Group 1, 2, 17 & 18 – names, properties, combine with?
Page 133

58. Differences and similarities?
Ionic
Molecular
Attraction between particles of opposite charges.
High melting point, good electrical conductivity, distinct crystal shape.
All solid at room temp.
When dissolved in water, will conduct electricity.
Non-metals combining.
Can be solids, liquids or gasses at room temp.
Insulators-poor conductors of electricity.
Relatively low melting and boiling points (forces between molecules are weak).

59. Review:
Pages 146 & 147 (Naming ionic compounds and using ion charges and chemical names to write formulas).
Page 152 (Writing formulas for molecular compounds and naming of molecular compounds).