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Unit 1
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Properties of matter and changes of matter
Matter: anything that has mass and takes up
space
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Any substance that has a definite
composition
◦ Always made of the same stuff in exactly the same
proportions
 Examples: H2O, NaCl, C12H22O11
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All around us
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Changes in chemicals
◦ Ex: things growing, food cooking, taking a photo
(film)
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We use reactions to produce chemicals
◦ Ex: plastics, acids
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Solid, Liquid, Gas
◦ What is the difference between ice, water, steam?
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Solid
◦ Definite shape, definite volume
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Liquid
◦ No definite shape, definite volume
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Gas
◦ No definite shape, no definite volume
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2 types of solids
◦ Crystalline solid (crystal)
 Arranged in an orderly, repeating pattern
◦ Amorphous solid (without form)
 Arranged randomly – no pattern
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Definite shape
Definite volume
Nonfluidity
Definite melting point
High density
Incompressibility
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The total 3-dimensional array of points that
describe the arrangement of particles in a
crystal is called a crystal lattice.
1 repeating piece
is a unit cell
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Definite volume
Fluidity – able to flow
Relative high density
Relative incompressibility
Dissolving ability
Ability to diffuse
Tendency to evaporate and boil
Tendency to solidify
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Properties that can be measured or observed
without changing it’s identity
◦ Length, mass, color, odor, density, boiling point,
melting point
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Matter can change
◦ Ice melts, water fogs a mirror, bike spokes rust, red
clothes fade, milk sours
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2 types of changes
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A change in which the identity of a substance
does not change
◦ Change physical properties
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Melting, freezing, dissolving, crushing,
boiling
Pressure (atm)
(Freezing
Points)
Liquid
1
Solid
(Boiling
Points)
.
0
Gas
(Triple
Point)
100
Temperature (oC)
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Also called a chemical reaction
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Things turn into something new
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2 parts of a chemical reaction
◦ Reactants – things that react
◦ Products – things that are produced
Reactant + Reactant  Product + Product
Propane + Oxygen  Carbon Dioxide + Water
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1.
2.
3.
4.
1 of 4 things must happen
A gas is produced
Formation of a precipitate
Release of heat and light
Color change
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All matter is made of atoms
◦ There are 115 kinds of atoms
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Matter is either a pure substance or a mixture
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2 Types
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Can it be separated?
◦ Yes, it is a compound
 H2O, NaCl, C6H12O6, H2SO4
◦ No, it is an element
 H, O, Na, Au, Pb
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2 Types
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Is it all the same?
◦ Yes, it is a homogeneous mixture
 Tap water, air, apple juice
◦ No, it is a heterogeneous mixture
 Salt/pepper, orange juice, choc chip cookie
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3 kinds of mixtures
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1. Solution
◦ Soluble – will dissolve
◦ Forms a homogeneous mixture
 Very small particles
◦ 2 Parts of a solution
 Solute – stuff that dissolves
 Solvent – stuff that the solute dissolves in
Solute
Solvent
Example
Gas
Gas
Air
Gas
Liquid
Soda Water
Gas
Solid
-
Liquid
Gas
Humidity
Liquid
Liquid
Juice in water
Liquid
Solid
-
Solid
Gas
Sulfur in air
Solid
Liquid
Kool Aid
Solid
Solid
Alloy (Brass)
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2. Suspensions
◦ Heterogeneous mixture that settles
◦ Large particles
◦ Muddy water, Italian salad dressing
 (anything that must be shaken)
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3. Colloids
◦ Intermediate sized particles
◦ Particles disperse
 2 parts of a colloid
◦ Tyndall Effect
 Seeing a beam of light
 (separates colloid from solution)
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Colloid
Phase
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Gel
solid dispersed in liquid
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Liquid emulsion
liquid dispersed in liquid
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Foam
gas dispersed in liquid
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Smoke
solid dispersed in gas
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Fog
liquid dispersed in gas
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Smog
solid & liquid dispersed in gas
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Solutions
Homogeneous
Very small
particles
Does not
separate
No light
scattering
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Colloids
Homogeneous
Intermediate
sized
Does not
separate
Tyndall effect
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Suspensions
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Heterogeneous
Large particles
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Separates
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No Tyndall
effect
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Increasing the Rate of dissolving
◦ 1.Increase the surface area of solute
◦ 2. Agitating the solution
◦ 3. Heating the solvent
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Electrolyte
◦ A solution that has ions in it and can conduct
electricity
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Saturated solution
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Unsaturated solution
◦ Contains the maximum amount of solute
◦ Contains less than the maximum amount of solute
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Supersaturated solution
◦ Contains more than the maximum amount of solute
 (Rock candy, crystals)
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1. Types of solvents and solutes
◦ Like dissolves like
 Refers to polarity
 Water is a polar molecule
 Oil is a nonpolar molecule
 If they are the same polarity, the compounds are
miscible (mixable) - salt in water, vinegar in water
 If they are not soluble, they are immiscible (not
mixable) - oil in water, salt in oil
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2. Pressure
◦ Under pressure a gas will enter and dissolve in a
liquid
 fizz in a bottle of pop
◦ If pressure is released, the liquid can’t hold as
much gas
 Effervescence
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3. Temperature
◦ Warmer liquids hold less gas
 Burp more from warm pop