Chemistry - Science 10
REVIEW
Classification of Matter
MATTER
MIXTURES
SUSPENSIONS
Particles of one of the
substances remain
partly
clumped together
Ex/Orange Juice
PURE SUBSTANCES
SOLUTIONS
Particles of the
different substances
are completely mixed
together.
Ex/ Coffee with sugar
MECHANICAL
Particles of the different
substances remain
clumped together. Ex/
cereal,
nuts,bolts,pepper
ELEMENTS
COMPOUNDS
Contain only a
single type of atom
Contain 2 or more
types of atoms, joined
together.
Ex/ Gold-Au or Calcium-Ca
Ex/ Ethanol CH3CH2OH
Two Types of Mixtures
 Heterogeneous Different from place to place
 Not evenly mixed
 Included suspensions and mechanical mixtures
 Chocolate chip cookie, gravel, soil
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HomogeneousThe same throughout
Evenly mixed
solutions
Kool-aid, sea water, air
Pure Substance
 Elements- Simplest kind of matter
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Can’t be broken down further
All one kind of atom
About 120 kinds of elements
Each has a 1 or 2 letter symbol
Each behaves differently
Everything else is made up of them
Pure Substances
 Compounds- Made of two or more elements
chemically combined
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Atoms combine together to make molecules
All molecules of a compound are the same
 They mix in the same ratio
Compounds behave completely differently
from the elements that make them
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Ex. Water H2O–liquid puts out fire: hydrogen
burns, oxygen supports combustion
Physical vs. Chemical Changes
 Physical Changes: No new substance has been
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formed.(ex/ ice cube melting, or crumpling a piece of
paper.
All the molecules stay the same
Might look a little different
Keeps original properties
Changing phases
Making a mixture
Cutting
Grinding
Dissolving
 Chemical Changes: If one or more
substances have been produced, substances
with properties different from the starting
materials, then a chemical change has taken
place.
 Products are not at all like the reactants
 Makes new odor, color, etc.
 Completely new properties
Clues to tell you a “Chemical Change” has taken place:
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A new colour may appear.
Heat or light may be given off.
Bubbles of gas may be formed.
Solid material may form in a liquid.
The change may be difficult to reverse.
Chemical Reactions
 Chemical Reaction is another term for chemical
change. (ex. Fast- fireworks, or slow- rust)
 Starting materials are called reactants. (Found on
the left of the arrow in a chemical equation)
 Any substance produced in the reaction is a
product. (on the right of the arrow).
Word Equations
 Word equations tell us the names of the reactants
and products in a reaction. Reactants on the left,(of
the arrow) products on the right.
 Note: It does not tell us the amounts of the
atoms/elements required to make the reaction go!
 Ex/ SodiumChlorine-----Sodium Chloride
Mass and Chemical Change
 The Law of Conservation of Mass:
In a chemical reaction, the total mass of the
reactants is always equal to the total mass of the
products
Chemical Formulas
 Tell the element and number of atoms in a
molecule
 Symbols identifies the element
 Subscripts tell the number of atoms
 Don’t write one as a subscript
Chemical Formulas
H2O
subscript
2 Hydrogen atoms 1 Oxygen atom
Chemical Formulas
C12H22O11
12 Carbon atoms
11 Oxygen atoms
22 Hydrogen atoms
Chemical Properties
 Used to describe how substance reacts
 How it changes
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By combining with other substances
Or breaking apart
 Reactivity how a substance combines with
other substances
 Things like flammability, rusting, etc.
Physical Properties
 Can be observed or measured without
changing the composition
 Melting point , boiling point, hardness, odor,
ability to conduct electricity and heat
 Density – how heavy something is for its size
 Ratio of mass to volume
 If the density of substance is less than its
surroundings, it floats
Density
 Found by dividing the mass by volume
D= m
V
 Units of g/mL or g/cm3
 Water has a density of 1 g/mL
Law of Conservation of Energy
 In all chemical changes, energy cannot be
created or destroyed
 All the energy you put in, you get out
 It might be hard to count
KINETIC MOLECULAR
THEORY
•All matter is made up of extremely
small particles that are always
moving (atoms and molecules) with
spaces between them
•The particles are close together
and slowest moving in solids, and
farthest apart and fastest in gases
•Heat makes the particles move
faster
Changes of State of Matter
GAS
condensation
sublimation
evaporation
LIQUID
sublimation
melting
solidification
SOLID