Matter
Are all the particles alike?
YES
NO
Pure Substance
Are the particles one
kind of atom?
YES
Element
NO
Compounds
or Molecules
Mixture
Are the particles well-mixed
and mixed evenly?
YES
NO
Homogeneous Heterogeneous
Mixture
Mixture
(Solutions)
For something to
dissolve in water,
the water
molecules need
to break the
bonds between
the solute
molecules
Solutions (homogeneous mixture)
 very small particles evenly distributed
 often difficult to separate
 examples: metal alloys, milk, salt water,
Kool Aid®
Dissolving
 the substance that is dissolved is called the solute
 the substance that does the dissolving is the
solvent
 a substance that dissolves in another substance is
soluble; if it can’t, it is insoluble
 solubility describes the amount of solute that can
be dissolved in a volume of solvent
○ an unsaturated solution will dissolve more solute
○ can not dissolve any more solute in a saturated solution
Acids and Bases
Acids

Properties
 a substance that produce hydrogen ions (H+) in
solution
○ the more H+ dissolved in water, the stronger the acid
 can taste sour
 corrosive (“eat away” metals)
 dehydrating agents (remove water from materials-
skin!)

Common acids
 sulfuric acid: most widely used
chemical in the world, car
batteries, production of fertilizers
 phosphoric acid: make fertilizers
and detergents
 nitric acid: fertilizers and
explosives
 hydrochloric acid: stomach acid
and to pickle (clean) metals
Bases (also called alkaline when in water)
 Properties
 “opposite” of an acid
 a substance that produce hydroxide ions (OH-)
in solution
○ the more OH- dissolved in water, the stronger
the base
 feel slippery (soap)
 may taste bitter
 Common
bases
 ammonium hydroxide:
most common, household
cleaning agent, and in
fertilizers
 magnesium hydroxide:
laxative, antacid
 sodium hydroxide: drain
and oven cleaner
Measuring Acid/Base Strength

pH scale
 each increase or decrease is 10X change in
concentration

indicators are chemicals that change color in an
acid or base
Neutralization

the chemical reaction between an acid and
base that produces “a salt” and water
 acid + base → salt + water
○ HCl + NaOH → NaCl + H2O