Post on 29-Jan-2016
Unit 2 – Matter
Classification of Matter
Properties of Matter
A. Matter Flowchart
MATTER
Can it be physically separated?
Homogeneous Mixture
(solution)
Heterogeneous Mixture Compound Element
MIXTURE PURE SUBSTANCE
yes no
Can it be chemically decomposed?
noyesIs the composition uniform?
noyes
Colloids Suspensions
Pure Substances
1. Element composed of identical atoms EX: copper wire, aluminum foil
Pure Substances
2. Compound
composed of 2 or more elements in a fixed ratio
properties differ from those of individual elements
EX: table salt (NaCl)
Mixtures
Variable combination of 2 or more pure substances.
Heterogeneousuneven distribution
(suspensions & colloids)
Homogeneouseven distribution
( solutions)
Mixtures
1. Solution homogeneous very small particles no Tyndall effect Tyndall Effect
particles don’t settle EX: rubbing alcohol
Mixtures
2. Colloid heterogeneous medium-sized particles Tyndall effect particles don’t settle EX: milk
The Tyndall Effect
Colloids scatter light, making a beam visible. Solutions do not scatter light.
Which glass contains a colloid?
solutioncolloid
Mixtures
3. Suspension heterogeneous large particles – can see Tyndall effect particles settle
(needs to be shaken) EX: fresh-squeezed
lemonade
Mixtures
Examples:
jello
muddy water
Fog
saltwater
Italian salad dressing
colloid
suspension
colloid
solution
suspension
Mixtures vs. Compounds
Components may be in any proportion
Individual components retain their own identities
Components may be separated physically
When mixture is formed there is little to no evidence of a reaction
Components are in fixed proportions
Individual components lose their identities, new set of properties result
Components may be separated only chemically
When compound is formed there is evidence of a reaction
Physical Separation Techniques
Difference in Densities (density column – some objects float in others)
Filtration (separate solids from liquids)
Magnetism Chromatography Distillation (separation by boiling
points)
Separation of a MixtureSeparation of a Mixture
The constituents of the mixture retain The constituents of the mixture retain their identity and may be separated by their identity and may be separated by physical means.physical means.
Separation of a MixtureSeparation of a Mixture
The components of dyes such as ink may be separated by paper chromatography.
Separation of a MixtureSeparation of a Mixture
Distillation
Types of Properties
PhysicalProperties that
describe the substance itself, rather than describing how it can change
Example: boiling point, color, size
ChemicalProperties that
describe the substances ability to undergo changes that transform it into other substances
Example: charcoal has the ability to burn in air
Types of Physical PropertiesTypes of Physical PropertiesExtensive propertiesExtensive properties
Intensive propertiesIntensive properties
Volume
MassEnergy Content (think Calories!)
depend on the amount of matter that is present.
do not depend on the amount of matter present.
Melting point
Boiling point
Density
Changes in Matter
Physical Change
Change in form or state of matter without altering chemical composition
Examples: slicing a banana, boiling water, dissolving sugar
Chemical Change
Changing substance into new substance by reorganizing atoms…chemical bonds are made or broken
Examples: burning, rusting, copper turns green
5 Indicators of a chemical change
Color Change Light emitted (glow sticks, candle
burning) Temperature change (happens on its
own – you don’t supply heat) Precipitate forms (solid from 2 liquids) Gas production (you see bubbles)
Three PhasesThree Phases
Solids
Definite shape/definite volume
Molecules are tightly packed, but can still move slightly
Most Dense state of matter (because particles are the closest)
Liquids
Definite volume/no definite shape (takes the shape of its container)
Fluid – because it “flows”
Particles are not as close as solids, but are more dense than gases
Gases
No definite shape or volume
Least dense of the 3 states of matter because the particles are far apart
Which state of matter are they?
Phase Phase DifferencesDifferences
SolidSolid – definite volume and shape; particles packed in fixed positions.LiquidLiquid – definite volume but indefinite shape; particles close together but not in fixed positionsGasGas – neither definite volume nor definite shape; particles are at great distances from one another
Phase Changes
Freezing (liquid to solid) Melting (solid to liquid) Evaporation (liquid to gas) Condensation (gas to liquid) Sublimation (solid to gas) Deposition (gas to solid)
**** Phase changes are PHYSICAL changes!!!!