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What is matter?. a . anything. c . everything. b . something. d . nothing. a, b, & c If it has mass & volume , it’s matter. How do we identify matter ? “matter” = stuff. By what we can see , smell , taste , feel , hear , measure , … we call these things “ properties ”
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What is matter? a. anything c. everything b. something d. nothing a, b, & c If it has mass& volume, it’s matter
How do we identify matter? “matter” = stuff • By what we can see, smell, taste, feel, hear, measure, … we call these things “properties” • Stuff can have 2 types of properties: • Physical • Chemical
Physical Properties (measured without changing the stuff’s identity) State: The organization of matter (e.g. solid, liquid, gas) The visual perception of reflected wavelengths of light Color: How something feels on the skin (soft, course, bumpy) Texture: How solid/hard something is Hardness: How well it allows heat or electricity to flow Conductivity: Temperature that it freezes/melts/boils Freezing/melting/boiling point: Ability to be hammered into sheets Malleability: Ability to be pulled into wires Ductility: How shiny it is Luster: How well it flows (or how thick it is) Viscosity: Ability to be dissolved in water Solubility: The mass of stuff per volume (#grams/1 mL) Density:
Chemical Properties (changes the stuff’s identity when it’s measured) • Reactivity • Toxicity • Ignition point • Flammability At what temp. does it burn?
Everything changes… If the change can be undone, it was just a physicalchange. For example: • water freezing into ice • throwing wood in a chipper • chewing up a carrot • The matter doesn’t change its chemical composition… it has all the same physical properties it did before the change.
Identifying a physical change… • Ask yourself: “Self, can I undo that change?” • Or “Does this stuff have all the same properties as it did before?”
Everything changes… If the change can NOT be undone, it was a chemical change. For example: • a nail corrodes/rusts • burning wood chips • I digest a carrot • The matter changes its chemical composition… it actually becomes new & different stuff.
Identifying chemical changes… • When stuff changes it’s identity (chemically changes), it is easy to tell. You may see… • Bubbles • A color change • Light • Heat • Change in odor/taste
Intensive and Extensive Properties • Physical properties may be intensive or extensive. • “in” means “inside” • “ex” means “outside”
What are intensive properties? • Intensive properties (such as density, color, conductivity, ductility, boiling point … etc.) do not depend on the size of the sample of matter and can be used to identify substances.
What are extensive properties? • Extensive properties such as mass and volume and length depend on the quantity of the sample.
QUIZ TIME! Which of the following is NOT classified as matter? A . Rock B . Light C . Air D . steam Which of the following is a physical property of matter? A. reactivity B. pH C. solubility D. toxicity Which of the following is a chemical property of matter? A. Viscosity B. reactivity C. texture D. density Density is what type of property? A. chemical property B. intensive property C. extensive property D. dependent property
What are "substances"? A substance cannot be further broken down or purified by physical means. A substance is matter of a particular kind. Each substance has its own characteristic properties that are different from the set of properties of any other substance. Substances can be either an element or a compound
Characteristics of Pure Substances • Fixed composition • Cannot be separated into simpler substances by physical methods (physical changes) • Can only be changed in identity and properties by chemical methods • Properties do not vary
What is a pure substance? Compounds • Can be decomposed into simpler substances by chemical changes, always in a definite ratio Elements • Cannot be decomposed into simpler substances by chemical changes • Examples: C (carbon) O (oxygen) H (hydrogen) • Examples: CO2 H2O C6H12O6
What is a mixture? Mixtures are two or more substances that are NOT chemicallycombined… (they’re only physically combined) They don’t have constant boiling, melting or freezing points
Characteristics of Mixtures • Variable/different composition • Components retain their own properties • May be separated into pure substances by physical methods
Homogenous Mixtures Homogenous mixtures look the same throughout but can be separated by physical means (dissolution, centrifuge, etc.). Examples: milk, sugar water, jell-o
What are solutions? Solutions are homogenous mixtures that do not scatter light. They are easily separated by distillation or evaporation. Examples: sugar water, salt water, air
Heterogenous Mixtures Heterogeneous mixtures are composed of large pieces that are easily separated by physical means (ie. density, boiling point, magnetization, your fingers).
Indicators of Heterogenous Mixtures • Do not have same composition throughout • Components are distinguishable Examples: fruit salad, vegetable soup, etc.
Which of these is a compound??? Which of these is a homogenous solution???
Name 2 Extensive properties::: • Name 2 Intensive properties:::
States of Matter (And how the Kinetic Molecular Theory explains them all) • Solids • Liquids • Gases • *Plasma
Kinetic Molecular Theory …Translation: The movement of the molecules determines the state
Vocabulary • Mass- The amount of matter in a thing • Volume - the amount of space a thing takes up/occupies • Condensation - the process of changing state from a gas to a liquid. • Evaporation - the process of changing state from a liquid to a gas. • Melting - the process of changing state from a solid to a liquid. • Sublimation - the process of changing state from a solid to a gas without going through the liquid stage.
Solids • Have a definite shape • Have a definite volume • This means they are not compressible Kinetic Molecular Theory Molecules are held close together and there is very little movement between them.
Liquids • Have an indefinite shape • Have a definite volume • So are liquids compressible? Kinetic Molecular Theory Atoms and molecules have more space between them than a solid does.
Gases • Have an indefinite shape • Have an indefinite volume • Compressible yet? Kinetic Molecular Theory Molecules are moving in random patterns with varying amounts of distance between the particles.
Changing States The state/phase of something can be changed by either adding/subtracting heat AND/OR pressure
How can we melt a solid to a liquid? • How can we boil a liquid to a gas? • How can we condense a gas to a liquid? Add heat Add heat… or lower the pressure Remove heat… or raise the pressure
check yo’self Definite Indefinite Indefinite Definite Definite Indefinite NO YES NO Close Very far Very Close
DENSITY • Density= Mass of a substance in a sample divided by sample’s volume. • = mass/volume • = grams/mL • = grams/cm3 *It does not matter how much of the substance you have… the density will always be the same
Density • A piece of pure chalk has a mass of 17 grams and occupies 6.8 mL of volume. Find density of this piece of chalk… • Mass = 17 g • Volume = 6.8 mL • Density = mass / volume = 17 g / 6.8 mL • Density = 2.5 g / 1 mL
On earth we live upon an island of "ordinary" matter. The different states of matter generally found on earth are solid, liquid, and gas. In 1879, a fourth state of matter was identified…
Plasma Plasma is by far the most common form of matter. Plasma in the stars and in the tenuous space between them makes up over 99% of the visible universe and perhaps most of that which is not visible.
Star formation in the Eagle NebulaSpace Telescope Science Institute, NASA (below) (Above) X-ray view of Sun from Yohkoh, ISAS and NASA
Plasma radiation within the Princeton Tokamak during operation.
Plasma consists of a collection of free-moving electrons and ions - atoms that have lost electrons. Energy is needed to strip electrons from atoms to make plasma. The energy can be of various origins: thermal, electrical, or light (ultraviolet light or intense visible light from a laser). With insufficient sustaining power, plasmas recombine into neutral gas.
Plasma can be accelerated and steered by electric and magnetic fields which allows it to be controlled and applied. Plasma research is yielding a greater understanding of the universe. It also provides many practical uses: new manufacturing techniques, consumer products, and the prospect of abundant energy.