Matter_Prop_and_Chang_Unit1nnnnnnnnn.ppt

Matter – Properties and
Matter – Properties and
Change
Change
The Physical Behavior of Matter

Types of Matter
Types of Matter
Pure substances (sometimes just called
substance)
– A sample of matter is a pure substance if its
composition is the same throughout the sample
– Examples:
 oxygen gas (an “element”);
 water (a “compound”)

Two Types of Pure
Two Types of Pure
Substances
Substances
Elements – substances that can not be
broken down or decomposed into simpler
substances by chemical means
– Examples: oxygen, nitrogen, silver, sodium,
etc.
 Periodic Table of the Elements
– Open reference Tables and find the periodic table of
elements.

The Periodic Table
The Periodic Table

Two Types of Pure
Two Types of Pure
Substances (Con’t)
Substances (Con’t)
Compounds - composed of two or more
elements that are chemically combined in
definite proportions by mass.
– Examples: water, table salt (sodium chloride),
sugar,

Water is a Compound
Water is a Compound
Representation of H2O molecules.
 For every oxygen atom
(big red ones), there are
two hydrogen atoms
(little blue ones)
 The hydrogen atoms
are chemically bound to
the oxygen atoms
 The formula for water
is H2O

Compounds
Compounds
 Unlike elements,
compounds can be
broken down into
simpler substances by
chemical means.
 The properties of a
compound are
different from those of
its component
elements

Types of Matter
Types of Matter
Mixtures – a mixture is a combination of
two or more pure substances in which each
pure substance retains its individual
qualities.
In a mixture, the pure substances can be
separated by physical means.
Unlike pure substances, the composition of
a mixture is not definite or fixed.

24 karat gold is a pure substance
However, 18 karat and 14 karat gold
are actually mixtures (known as alloys)
containing gold, copper, and silver.

 Table salt and
water together
(salt-water) are
an example of a
mixture.
 They can be
physically
separated by
boiling away
the water.

Matter_Prop_and_Chang_Unit1nnnnnnnnn.ppt

Two Types of Mixtures
Heterogeneous Mixture – is one that does
not blend smoothly throughout and in
which the individual substances remain
distinct.
– heterogeneous mixtures have varying
compositions
Examples:
– sand and water; chocolate chip cookies;
concrete

 Homogeneous Mixture - is one in which the
composition is constant throughout.
 Homogeneous Mixtures always have a single
phase (solid, liquid or gas)
 Homogeneous mixtures are also refered to as
solutions (even if they’re not liquid, such as
alloys)
 Examples:
– salt water; alloys; lemonade

Mixtures vs. Substances
Mixtures vs. Substances
Worksheet
Worksheet
Particle Diagrams

Physical Properties of Matter
Physical properties can be
observed or measured without
changing the samples
composition

Physical properties include
density, color, odor, taste,
hardness, melting point, boiling
point

Extensive Properties - depend on the
amount of substance present (examples:
length, mass)
Intensive Properties - independent of the
amount of substance present (examples:
density, melting point)
– A substance can often be identified by its
intrinsic properties.

Chemical Properties of Matter
The ability of a substance to
combine with or change into one or
more other substances is called a
chemical property.

The inability of a substance to
change into another substance
is also a chemical property.

Let’s Practice
Let’s Practice
Study Guide Section 3.1 (Page 13)

Lab
Lab
Physical and Chemical Properties of Wood

The Physical States of
The Physical States of
Matter
Matter
Solids
Liquids
Gases

The Solid Phase
The Solid Phase
Contains matter that is held in a
rigid form.
Solids have a definite volume and
shape.
Strong attractive forces between
the particles hold them in fixed
locations.
Solids are incompressible.

The Liquid Phase
The Liquid Phase
Particles are not held together as
rigidly as those in the solid phase
Liquid phase particles are able to
move past one another – because
of this liquids don’t have a definite
shape. They take the shape of their
container.

The Liquid Phase
The Liquid Phase
A liquids volume is constant –
regardless of the size and shape of
the container.
Liquids are virtually
incompressible.

The Gaseous Phase
The Gaseous Phase
Particles have minimal attractive
forces holding them together.
Gases have neither a definite shape
nor volume

The Gaseous Phase
The Gaseous Phase
Gases spread out indefinitely unless
confined in a container.
In a closed container, the gases expand
to fill the volume of the container.
A vapor is the gaseous phase of a
substance that is a liquid or solid at
normal conditions.

Let’s Practice
Let’s Practice
Study Guide Sect 3.1 (page 14)

Physical Changes
Physical Changes
Changes that alter a substance
without changing its composition
are known as physical changes
– Bending, crumpling, cutting,
grinding, etc.
– Melting, evaporating, condensing,
etc.

Chemical Changes
Chemical Changes
A process that involves one or
more substances changing into
new substances is called a
chemical change.

Let’s Practice
Let’s Practice
Study Guide Section 3.2 (Page 15)
Use your Textbook

Chemistry Lab
Chemistry Lab
Conservation of Mass

Law of Conservation of Mass
Law of Conservation of Mass
Mass is neither created nor
destroyed during a chemical
reaction - it is conserved.
In a chemical reaction matter is
rearranged.

The equation form of the law
of conservation of mass
Massreactancts = Massproducts

Cons. Mass
Cons. Mass
SAMPLE PROBLEM
SAMPLE PROBLEM
In an experiment, 10.00
grams of water was
separated by
electrolysis (a chemical
process) into hydrogen
gas and oxygen gas.
1.11 grams of hydrogen
gas were collected.
How many grams of
oxygen were collected?

Solution
Solution
Massreactancts = Massproducts
Masswater = Masshydrogen + Massoxygen
10.00 gwater = 1.11 ghygrogen + Massoxygen
Massoxygen = 8.89 g

We apply the law of
conservation of mass to
determine the missing mass in
chemical equations.

Sample Problem
Sample Problem
If 103.0 g of potassium chlorate are
decomposed to form 62.7 g of
potassium chloride and oxygen gas
according to the equation
2KClO3 ------> 2KCl + 3O2
How many grams of oxygen are
formed?

Law of Definite Proportions
An important characteristic of
compounds - the elements
comprising them combine in
definite proportions by mass.

The Law of Conservation of
Mass applied to compounds:
–The mass of the compound is
equal to the sum of the masses of
the elements making up that
compound.

Let’s Practice
Let’s Practice
 What is the mass of a water molecule?
 Well… water is H2O. So for each molecule, there
are 2 hydrogens and one oxygen.
 How do we determine the mass of hydrogen and
the mass of oxygen?
– Reference Tables (Periodic Table)

Let’s Practice (con’t)
Let’s Practice (con’t)
The mass of one hydrogen is 1.00794
– We can usually round this to one.
The mass of one oxygen is 15.9994
– We can usually round this to 16.
So… the mass of one water molecule is
(2 hydrogens x 1) + (1 oxygen)(16) = 18

Let’s Practice Some More
Let’s Practice Some More
Determine the mass of…
Table salt (NaCl)
Ammonia (NH3)

% Composition
% Composition
The ratio of the mass of each element to the total
mass of the compound is called the percent mass
(or, more generally, the percent composition)
% composition by mass = mass of part/mass of whole x 100
(Reference Tables Table T)

Sample Problem
Sample Problem
# 22 in text page 76
If 3.5 grams of X reacts with 10.5 grams of
Y to form the compound XY, what is the
percent by mass of X in the compound?
What is the percent by mass of Y?

Solution
Solution
% mass = (mass part / mass whole) x 100
Mass of whole compound = mass X + mass Y
Mass of whole compound = 3.5g + 10.5g
Mass of whole compound = 14.0 g
% mass compound X = (3.5 g / 14.0 g) x 100
% mass compound X = 25%
% mass compound Y = (10.5 g / 14.0 g) x 100
% mass compound Y = 75%

Homework
Homework
Homework #4
(Skip #16)

Temperature - Revisited
Temperature - Revisited
The temperature of a
substance is a measure of the
average kinetic energy of its
particles.

Temperature
Temperature
The temperature difference
between two bodies indicates the
direction of heat flow.
– Heat flows from an object with
higher temp to an object with lower
temp (until they reach the same
temp)

Temperature
Temperature
The average kinetic energy
depends only on the temperature of
the substance, not on the nature or
the amount of material.
– So, 10 g of water @ 500
C has greater
average kinetic energy than 600 g of
iron at 200
.

Temperature
Temperature
Temperature is measured using a
thermometer
Thermometers are calibrated using
two fixed reference points
– freezing point of water (solid-liquid
equilibrium)
– boiling point of water (liquid-gas
equilibrium

Celsius and Kelvin
Celsius and Kelvin
Temperature Scales
Temperature Scales
The Celsius and Kelvin scales
are related by the equation
K =
K = 0
0
C + 273
C + 273
(ref. tables)
(ref. tables)

Temperature Vs. Heat
Temperature Vs. Heat
Heat and temperature are not
the same.
Heat is a measure of the
amount of energy transferred
from one substance to another.

Separation of Mixtures
Separation of Mixtures

Separating Mixtures
Separating Mixtures
The properties of a mixtures
components often provide a way to
separate them
– Density
– Boiling and Freezing Points
– Molecular Polarity

Filtration
Filtration
Many mixtures are made up of a
solid and a liquid, where the solid
is not dissolved, but suspended
– sometimes you can decant

Filtration
Filtration
A filter is a material that allows
small particles to pass through
while trapping larger particles on
or in the filter material.
– The filter is a material containing
holes

Filtration
Filtration
Filtration is commonly used to
separate…
– A mixture of an undissolved solid in
a liquid
Example: sand and water
– Mixtures of gases and solids
Examples: Car and truck air filters;
furnace or A/C filters

Immiscible Liquids
Immiscible Liquids
Two liquids that are not soluble in
each other are termed immiscible.
– Example: Oil and Water
Can be separated by pouring off
the top liquid, or draining the
bottom liquid

Distillation Demo
Distillation Demo
Distilling Cherry Coke

Distillation
Distillation
Distillation can be used to
separate…
– Solids that are dissolved in liquids
(such as salt dissolved in water)
– Liquids that mix with each other
(known as miscible liquids)

Distillation
Distillation
For miscible liquids to be separated by
distillation, what physical property
must be different between them?
They must have different boiling
points.
Common example: alcohol and water

Chromatography
Chromatography
Different components of a mixture
often have different attractions for
substances not in the mixture.
– Example: when paper is dipped into
some inks, the water in the ink rises
by capillary action separates

Chromatography
Chromatography
Many different types of
chromatography - but in all types
the principle remains the same -
the components of the mixture
have different attractions with the
transporting medium.

Activity
Activity
Chromatography

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