Chemistry Unit 1: Nature of Matter

Physical Properties

Characteristics that can be observed without altering the identity or composition of the substance.

Chemical Properties

Characteristics that can only be obsevered by changing the identity or composition of the substance

Physical Change

Does NOT change composition or identity of the substance

Chemical Changes

DOES change the composition or identity of the substance

Solid state of matter

Definite shape

definite volume

Liquid state of matter

indefinite shape

definite volume

Gas state of matter

indefinite shape

indefinite volume

Law conversation of matter

Matter can not be created or destroyed - it is conserved

Hard-boliing an egg

Chemical change

Iron rusting

chemical change

souring milk

chemical change

boiling water

physical change

alcohol evaporating

physical change

Pure substance

same composition

mixture

can be spartated by physical changes; combination of pure substances

homogeneous mixture

same throughout different parts can not be distinguished

heterogeneous mixture

regions of mixture are different; parts can be distinguished

Filtration

separating solids from liquids

Distillation

Separating liquids based on boilling point

Chromatography

separating parts of a homogeneous mixture

Every last digit in every measurement is an

ESTIMATE

precision

how close two or more measure values are

Accuracy

how close a measured value is to the known/true value

All non-zero numbers are

SIGNIFICANT Ex: 725

Zeros between two other significant digits are

SIGNIFICANT Ex: 705m

Zeros after the decimal point at the END of a number are

SIGNIFICANT Ex: 23.000g

Zeros that are placeholders (end or begining of number but before decimal point) are…

NOT SIGNIFICANT Ex: 520 mL

For calculating sig figs with multiplication + division…

Look at the measured quantity w/ the LEAST numbers of sig figs

For calculating sig figs with addition + subtraction…

Look at the measured quantity w/ the LEAST numbers of decimal places

Density

Mass over volume; a substance can only float if its LESS DENSE

Centi (C)

1/100

1m = 100cm

1s = 100cs

Kilo (K)

1,000

1km = 1000m

1kg = 1000g

Mili (m)

1/1000th

1L = 1000mL

1g = mg