Upload
colin-wood
View
224
Download
1
Tags:
Embed Size (px)
Citation preview
KINETIC THEORY OF
MATTER.
What is matter?
• Anything that has mass and takes up space
Matter
Kinetic Theory of Matter…• All matter is made up of particles• Different substances have different
sized particles• Particles are always moving - move
faster at higher temperatures• Particles are held together by bonds that vary in strength
mixture Composed of two or more substances, but each keeps its original properties.
States o MatterSolids Liquids Gases
Space between particles
Very small Very small Large
Bond between particles
Strong (rigid structure)
Strong Very weak
Movement of particles
Vibrate in a fixed position
Roll over each other
Move freely
States of Matter
• Which state(s) have a definite shape?
• Which state(s) have a definite
volume?
• Which state(s) are able to be
compressed?
• Which state(s) can flow?
• Which state(s) have particles which
move?
States of Matter
Classifying Matter
Matter
Pure Substances Mixtures
HomogeneousMixtures
HeterogeneousMixtures
Elements Compounds
6
Most atoms are combined with others in nature.
PHASE CHANGECH3CH2OH (l) CH3CH2OH (g)
CHEMICAL CHANGE CH3CH2OH + 3 O2 2 CO2 + 3 H2O
Pure Substances and Mixtures
Pure substances are either:Elements OR Compounds
-cereal with milk- salad- trail mix- sand- cement
- milk- steel (iron and carbon)- fog
Pure water - H2O molecules.Salt - NaCl molecules.A ruby stone - Al2O3 molecules.
Carbon (in the tip of your pencil)Gold is made only of atoms of Gold.
Mixtures are: Homogenous OR Heterogeneous
(the same throughout) (vary throughout)
Classifying Matter
Pure Substances
Elements Compounds
…can be broken down into atoms
Examples: Carbon (in the tip of your pencil) is made solely of carbon atoms.
Gold is made only of atoms of Gold.
…can be broken down into molecules.
Examples: Pure water consists only of H2O molecules.Salt consists only of NaCl molecules.A ruby stone consists of Al2O3 molecules.
Models of Matter
Mixtures
Heterogeneous mixtures- different particles are large enough to be seen or felt.
Homogeneous mixtures -very well mixed-looks and feels like one substance (Solutions are homogeneous mixtures)
Examples:-cereal with milk- salad- trail mix- sand- cement
Examples:- milk- steel (iron and carbon)- fog
9
• Consist of only 1 type of atom
O O OO O
OO
O
O OOO
O
Oxygen Atom
Element
Example: oxygen
Elements-
• A group of two or more atoms linked together by a bond
O O
Examples: oxygen water
O
HH
Molecule-
• A group of two or more DIFFERENT atoms linked together by a bond Examples:
water salt
O
HH
Na
Cl
Compound-
•Compounds can be broken down into molecules
OHH
OHH
OHH
OHHO
HHO
HHO
HH
Water is a compound
Single water molecule
PRACTISE
Identify each of the following substances as either an element, compound, solution or mixture:a. Sodium bromide (solid white granules)b. An aqueous mixture of bluestone (copper
sulfate)c. Sulphur (a yellow powder)d. Iodine and alcohol (a brown liquid)e. Sand and sea salt (silicon dioxide and
sodium chloride)f. Waterg. Airh. sugar
Practise
PRACTISE
Each shape below represents an atom of a particular element. a) State whether each is a representation of a group of atoms or a group of molecules.b) State whether the diagram represents an element, a compound, or a mixture.
Practise
Write a definition for the following words:
• Pure substance• Mixture• Atom• Element• Molecule• Compound
• Mixture- Composed of two or more substances, but each keeps its original properties. A mixture can be physically separated into pure compounds or elements
• A pure compound has a constant composition with fixed ratios of elements.
Mixtures
HOMOGENEOUS MIXTURES• The prefixes "homo"-
indicate sameness.• A homogeneous mixture
has the same uniform appearance and composition throughout.
HETEROGENEOUS MIXTURES• A heterogeneous mixture
consists of visibly different substances or phases. The three phases or states of matter are gas, liquid, and solid.
• Substances change state when energy or heat is added to them
• Heat gives the particles more kinetic energy causing them to expand
Changes in states of matter
• Melting Point• Freezing Point• Boiling Point • Condensation Point
Changes in states of matter
In a physical change, the substance involved remains the same substance, even though it may change state or form.
In a chemical change, the original substance is changed into one or more different substances that have different properties.
Physical vs. Chemical Changes
Chemical or Physical?
Example: A burning candle
Physical:• solid becomes liquid• liquid becomes solid
Chemical:•Wax vapour becomes carbon dioxide, water and energy
How can we tell that a chemical change had occurred?
3
The following are clues that a chemical change has happened:
• Heat or light is given off
• Bubbles of gas are formed
• A new colour appears
• The change is difficult to reverse
• A solid material (called a precipitate) forms in a liquid
More examples
4
Chemical ChangePhysical Change
• tarnishing silver
• tearing clothes
• crumpling paper • bleaching your hair
• burning toast
• fireworks exploding
• rusting bicycle
• melting ice cream
• glass breaking
• spoiling food
• boiling water
• sawing wood