Composition/Constitution of Matter

Pure Substance

with fixed or define composition

has only one kind of particle

Two types:

1. Element

2. Compound

Element

a pure substance with only one kind of atom

may occur separately or as molecules

examples:

Cu

Na

Mg

H₂

Have No Fear Of Ice Cold Beer

mnemonics for the 7 diatomic molecules

Compound

a pure substance with two or more kinds of atoms

examples:

H₂O

NaCl

HCl

C₁₂H₂₂O11

CH₃COOH

Mixture

variable composition

physically combined and can be separated

types:

1. Homogenous

2. Heterogenous

Homogenous

evenly mixed mixture

examples:

Solutions

Colloids

Solutions

too small to be seen

cannot be separated by filtration

(<nm)

examples:

syrups

elixirs

tincture

Colloids

too small but not as small as solutions

(1nm-1mcm)

examples:

Milk

Gelatin

Mythylcellulose

Albumin

Fogs

Brownian Movement

a property of colloids

zigzag movements

caused by perfect elastic collision

uneven distribution of collision

zigzag

brownian movement is described as the ________ movement

Tyndall Effect

most common property of colloids

light scattering effect

Heterogenous

a type of mixture which is not evenly mixed

example: suspension

Suspension

(>1mcm)

dry powders mixed with specific amount of water at time of order