Unit 1: Matter and Energy

Substance

Pure; a formula can be written

Compound

2 or more elements chemically combined in a defined ration

Element

a simple substance that cannot be broken down into other substances by chemical means.

Mixture

• a physical combination of 2 or more substances

• NO formula exists

• substances in a mixture RETAIN their properties

Heterogeneous mixture

a non-uniform composition of different substances

Homogeneous mixture

• uniform composition of different substances

• Evenly mixed throughout

• all solutions are homogenous

Physical Property

can be detected without changing the substance

Malleable

ability to be hammered into thin sheets

Brittleness

tendency to shatter when struck (non metals)

Ductibility

ability to be pulled into wire (metals)

Tenacity

resistance to being pulled apart

Solubility 

ability of a substance to dissolve into another substance to form a HOMOGENEOUS mixture

3.53g/ml

Density

Phase changes

physical properties

Chemical Property

detection is accompanied by a change in the substance

Flamiblity/combustibility

ability to catch fire easily and burn

Oxidation/Corrosion

• substance losses electrons

• ex: burning of methane, food spoiling, bleaching

Reactants with acids and bases

substances react with acids by neutralizing them and producing new compounds

Intensive Property

does not depend upon sample size

Extensive Property

depends upon sample size

Temperature

measure of the average kinetic energy of a substance

Solidification

liquid as it cools and loses thermal energy; transforms into a solid state

Vaporization (boiling)

process where a substance changes from a liquid or solid into a gas

Deposition

gaseous substance directly transforms into a solid state without first passing through the liquid phase

Fusion (melting)

change from a solid to a liquid

Sublimation

direct change from a solid to a gas

Condensation

process where gas changes into a liquid

Endothermic

substance absorbs heat from it’s surrondings

• fusion

• vaporization

• sublimation

Exothermic

a chemical reaction that releases energy into it’s surrondings

• solidification

• condensation

In all phase changes….

• temp remains the same

Specific Heat

amount of heat required to change 1g of a substance

High specific heat

the substance heats up slowly 

• takes a large amount of energy to raise the temp

Boiling

vapor pressure= atmospheric pressure

Vapor pressure

pressure escaping

Atmospheric Pressure

pressure exerted by the atmosphere (pushing you down)