Chapter 3

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matter- occupies space and can be perceived by our senses

composed of atoms

molecules- 2+ types of atoms, have different geometric shapes

mass- amount of matter

weight- pull of gravity on matter

The state of matter is controlled by temperature and pressure.

solids- definite shape and volume

atoms/molecules are in fixed locations

maintain shape under outside forces

non-compressable

crystalline solid- geometrically arranged molecules

I.E. salt, diamond

amorphous solid- no order in the arrangement

i.e. glass, rubber

liquids- definite volume, not definite space

slight distances btwn molecules

fluid and flow; easily change shape in response to outside forces (slight ones)

relatively incompressible

gases- no definite volume or shape; vapor

spread out

fluid; easily compressible

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Phase Changes:

require energy

melting- solid to liquid

evaporation- liquid to gas

sublimation- solid to gas

release energy

freezing- liquid to solid

condensation- gas to liquid

deposition- gas to solid

Heating and Cooling Curves:

Show the relationship btwn temperature and time.

rising- gaining energy

plateaus- changing states

temperature will rise after entire substance changes state

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Law of Conservation of Mass- total mass remains constant during chemical reaction (Lavoisier)

chemical reaction- change in which 1+ substances are changed into different ones

reactants- substances that react,

products - the substances yielded

evidence of a chemical reaction- formation of a precipitate, change in color, or temperature, or the evolution of a gas

Intensive Properties: do not depend on the amount of mater present

i.e. color, hardness, density

Extensive Properties: depend on the amount of matter present

i.e. mass, weight, volume

Properties of Matter-

Physical- can be observed and measured w/out changing the identity of the matter

Chemical- describes a substance's ability to change into a new substance as a result of a chemical change

Physical Properties of Matter-

mass

color

volume

odor

texture

taste

luster

hardness

melting point

boiling point

phase

density

malleable- change of shape w/out breaking

ductile- made into a wire

sectile- ability to be cut w/ a knife

conductivity

Physical Changes in Matter- alters a substance w/out changing it's composition

i.e. changes in state, form, particle size

Chemical Properties of Matter-

ability to form new substances

reactions a substance will undergo

pH

reactivity with water

flammability/burning

Chemical Changes in Matter-

changes fundamental components

indicators of a chemical change-

absorption/release of heat and light

gas production

formation of a precipitate

production of sound

drastic color change

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Classification of Matter- matter is either a pure substance or a mixture

pure substance- same composition throughout and does not very sample to sample; cannot be separated by physical changes

all either elements or compounds (pure substances made of 2+ atoms chemically combined)

mixture - any substance; can vary in composition and from sample to sample

Law of Definite Proportions- aka, law of constant composition, a pure compound always contains the same definite proportions of the elements by mass

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Mixtures- a blend of 2+ types of matter, each of which retains its own identity and properties

can be separated by physical means

Homogeneous Mixtures- same all through, aka solutions

Heterogeneous Mixtures - not the same all the way through

colloid- dispersion of particles throughout another substance or solution- will display the Tyndall Effect

emulsion- liquid dispersed in a liquid

aerosol- liquid in a gas

gel- liquid in solid

Tyndall Effect- the scattering of light by colloid-sized particles

suspension- solid particles large enough to settle out of solution

i.e. paint, blood