Science 9 Unit 2: Chemistry

Transcription

1 Science 9 Unit 2: Chemistry

2 What is Chemistry?

3 Chemistry: The study of the composition, properties, and reactions of matter

4 Chemistry: Definition The study of the composition, properties, and reactions of matter Matter: Anything that has mass and takes up space

5 Chemistry: Definition The study of the composition, properties, and reactions of matter Matter: Anything that has mass and takes up space everything in our universe except forms of energy (heat, light, electricity, radiation and sound)

6 Properties of Matter Matter has Physical and Chemical properties

7 Physical Properties of Matter Properties that can be observed or measured without changing a substance Ex. colour, malleability, conductivity, magnetism, luster, density, texture, melting/ boiling points Iron: Shiny, grey, magnetic

8 Chemical Properties of Matter Properties observed only when one substance reacts with another Ex. Combustibility (burning), reactivity, toxicity rust Iron: reacts with oxygen to form

9 Chemistry Around Us

10 Chemistry Around Us H 2 0

11 Chemistry Around Us Chemicals may be: Natural or man-made Safe or potentially dangerous

12 Safety To use chemicals safely we need to: be aware of their chemical properties be aware of necessary precautions we should use when handling them

13 WHMIS WHMIS: Workplace Hazardous Materials Information System Canada-wide system designed to give employers and workers information about hazardous materials used in the workplace.

14 WHMIS There are 3 ways information on hazardous materials is provided: 1.labels on the containers 2.material safety data sheets (MSDS) with detailed information 3.worker education programs.

15 WHMIS Labels *All controlled products must have WHMIS labels Label includes: Name of the chemical The WHMIS hazard symbols Risks and precautions First Aid instructions Supplier s name and address A reference to the matching MSDS (with more information)

16 WHMIS Symbols Compressed Gas Gas under pressure Heat may cause contents to explode May explode if dropped

17 WHMIS Symbols Flammable and Combustable May catch fire or explode in the presence of a spark or open flame Flammables burn sooner and at lower temperature than combustibles

18 WHMIS Symbols Oxidizing increase the risk of fire if they come in contact with flammable or combustible materials

19 WHMIS Symbols Dangerously Reactive Very unstable May explode from shock, friction or increased temperature May react with water to produce toxic gas

20 WHMIS Symbols Corrosive Cause skin and eye irritation Tissue damage May eat through metals

21 WHMIS Symbols Poisonous and Infectious (Causing Immiediate and Serious Effects) May be fatal if inhale, swallowed or absorbed through skin

22 WHMIS Symbols Poisonous and Infectious (Causing Other Toxic Effects) Poisonous upon repeated exposure Can cause cancer, birth defects etc

23 WHMIS Symbols Biohazardous contain harmful microorganisms May cause disease

24 WHMIS Recall There are 3 ways information on hazardous materials is provided: 1.labels on the containers 2.material safety data sheets (MSDS) with detailed information 3.worker education programs.

25 General Lab Safety Read entire lab procedure before beginning Listen to teacher instructions Long hair should be tied back Lab coats and safety glasses should be worn If anything is broken or anyone is injured, notify the teacher No food, drink, or gum in the lab

26 Atomic Theory In science the terms law and theory have different meanings than they do in everyday language Think about what comes to mind when you hear these terms and write your own definition in the table provided

27 Atomic Theory Scientific Definitions: Theory Explanation of events, patterns, or relationships that have been observed over and over again How it happens Law Description of observations that are supported by reliable evidence What happens

28 Atomic Theory

29 Atomic Theory

30 Atomic Theory Recall: Chemistry is the study of matter (it s composition, properties, and reactions) To understand chemistry we must first understand matter

31 Atomic Theory Recall: Chemistry is the study of matter (it s composition, properties, and reactions) To understand chemistry we must first understand matter Atomic Theory includes the various descriptions of matter and how it behaves

32 Atomic Theory Atomic theory has evolved over hundreds of years Use your text book and worksheet to summarize the contributions of early scientists to our understanding of matter Pages 24-28

33 Atomic Theory Democritus First to suggest the smallest piece that you could divide something into is an atom Dalton: billiard ball model atom is the same throughout and is indivisible Thomson: raisin bun model negative electrons scattered throughout a positive area of the atom

34 Atomic Theory Rutherford: planetary model electrons circling the center of the atom proposed that the atom is mainly empty space with very small and heavy nucleus Bohr: orbital model electrons circling the nucleus at different energy levels away from the nucleus

35 Atoms Atom the smallest particle of an element that retains the properties of that element made up of subatomic particles called protons, neutrons, and electrons

36 Atomic Structure Atoms contain 3 types of sub atomic particles Subatomic Particle Symbol Charge Mass (amu) Location Proton p+ + 1 Nucleus Neutron n 0 1 Nucleus Electron e- - 0 Outside of nucleus in energy levels

37 Atomic Structure Protons and neutrons are inside the nucleus (centre) The electrons are arranged outside of the nucleus in levels The number of protons and number of electrons are equal so that charges balance