Physical & Chemical Properties & Changes

Anything that has mass and takes up space

Mass – a measurement that reflects the amount of matter

Weight – a measure of the amount of matter and the effect of Earth;s gravitational pull on that matter.

Matter

Solid – matter with its own definite shape and volume◦ Ex: wood, iron, paper, sugar

Liquid – matter that flows◦ Ex: water, blood, mercury

Gas – matter that flows to conform to the shape of its container and fills the entire volume◦ Neon, methane, air

States of Matter

States of Matter

State Shape Volume Compressible?

Solid Definite Definite No

Liquid Indefinite Definite No

Gas Indefinite Indefinite Yes

A characteristic that can be observed or measured without changing the samples composition.◦ Density◦ Color◦ Odor◦ Taste◦ Hardness◦ Melting point◦ Boiling point◦ Solubility

Physical Properties

Extensive Properties◦ Depends of how much (the extent) matter there is◦ Ex: mass, length, volume

Intensive Properties◦ Independent (does NOT depend) of how much

matter◦ Substance can often be identified by intensive

property◦ Ex: density, temperature

The ability of a substance to combine with or change into one or more other substances◦ Combustibility

Sodium reacts with water, may combust◦ Reactivity with other substances

Iron rusts when exposed to oxygen

Chemical Properties

Substance (Pure Substance)◦ Matter that has uniform and unchanging

composition◦ Only 1 type of matter present

Element◦ A pure substance that cannot be separated into

simpler substances by physical or chemical means Compound

◦ Combination of two or more different elements chemically combined

Mixture◦ Combination of two or more pure substances in

which each pure substances retains its chemical properties

Types of Matter

Classes of Matter

Matter

Pure substance mixture

element homogeneouscompound heterogeneous

Homogeneous Mixture-◦ Has a constant composition throughout◦ Single phase◦ Looks the same throughout◦ Also referred to as solutions

Heterogeneous Mixture-◦ Does not blend smoothly throughout◦ Individual substances remain distinct

Mixtures

ExamplesElement-Carbon-Iron-Gold-Mercury

Compound-Water-Carbon Dioxide-Table Salt-Aspirin

Homogenous Mix.-Air-Salt water-White gold-Brass

Heterogenous Mix.-Concrete-Milk-Wood-Sand

Metals – ◦ Have luster (shine)◦ Malleable (not brittle)◦ Ductile (can be drawn into wires)◦ Conduct heat and electricity

Nonmetals – ◦ Brittle◦ Poor conductors of heat and electricity

Metalloids – ◦ Have characteristics of both metals and

nonmetals

General Classes of Elements

A homogeneous mixture Composed of 2 parts

◦ Solvent – substance there is more of Dissolving substance

◦ Solute – substance that is added to solvent Dissolved substance

Solutions

Alter a substance without changing its composition

Identifying properties remain unchanged◦ Phase change◦ Breaking or cutting◦ Dissolving◦ Bend◦ Crumple◦ Split◦ Crush

Physical Changes

One or more substances changing into new substances

Different substances formed◦ Burning◦ Rusting◦ Decaying or spoiling◦ Fermentation◦ Acid reacting with metal

Chemical Changes

Heat gained or lost

Production of a gas

Formation of a precipitate

Color change

Signs of a Chemical Change

Ice changing to liquid waterPhysical change

Water breaking down into hydrogen and oxygen gases

Chemical change

Mass is neither created nor destroyed during a chemical reaction, it is always conserved.

Mass of reactants always equals mass of reactants.

Massreactants = Massproducts

Law of Conservation of Mass

Regardless of amount, a compound is always composed of the same elements in the same proportion by mass.◦ Water, H2O ◦ Always made of 2:H’s and 1:O no matter how

much water you have

Law of Definite Proportions

% by mass = Mass of Element X 100 Mass of Comound

Percent by Mass

When different compounds are formed by a combination of the same elements, different masses of one element combine with the same relative mass of the other element in a ratio of small whole numbers.

H2O vs. H2O2

Water has 2 H’s for every 1 O Hydrogen peroxide has 2 H’s for every 2 O’s

Law of Multiple Proportions

Use different properties of substances to separate them◦ Sand and iron filings◦ Sand and salt◦ Sand and water◦ Water and salt water◦ Oil in water (immiscible liquids)◦ Mixture of pigments

Methods of Separating Mixtures

Remove iron with magnet

Dissolve salt, evaporate water

filterDistill the water

Settle and extract less dense liquid

Paper chromatography

ChromatographyDistillation

First letter is ALWAYS capitalized Second letter, if there is one, is NEVER

capitalized Co and CO are very different! Some elements use their Latin name

◦ 2 O means 2 oxygen atoms◦ O2 means 2 oxygen atoms are chemically

bonded together

Chemical Symbols