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Chemistry Unit Seven

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Chemistry Unit Seven Matter and Energy Matter Pure Substances Mixtures Elements Compounds Homogeneous Heterogeneous Classification of Matter Solution Suspension ... – PowerPoint PPT presentation

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Title: Chemistry Unit Seven


1
Chemistry Unit Seven
  • Matter and Energy

2
Matter
  • Matter
  • anything that has a mass and takes up space.
  • Law of Conservation of Mass/Matter
  • Matter cannot be created or destroyed in an
    ordinary chemical reaction just rearranged to
    form different substances
  • Matter can be described using properties..

3
Types of Properties
4
Characteristics of Matter
  • Physical Properties
  • Characteristics of a substance that can be
    observed without the production of a new
    substance.
  • Examples
  • Color,smell, taste, hardness, density, texture,
    melting/boiling/freezing points, magnetic
    attraction, solubility, electrical conductivity,
    temperature, state or phase

5
Two Types of Physical Properties
  • Extensive
  • Depends on the particular sample
  • examples volume, mass, weight, shape, etc
  • Intensive
  • Depends on the type of matter ? NOT size of
    sample
  • examples color, melting point, specific heat,
    density, appearance, etc

6
Characteristics of Matter
  • Chemical Properties
  • describes how a substance reacts or fails to
    react with other substances to produce new
    substances.
  • Examples
  • Oxidation, Corrosion, Hydrolysis, Combustion,
    Flammability, Reaction to Acid or Base.

7
Two Types of Changes
  • Physical Change
  • an alteration of a substance that only changes
    the physical properties of the substance.
  • Does not change the chemical composition of the
    matter!!

8
Characteristics of Matter
  • Chemical Change
  • an alteration of the chemical composition of a
    substance that results in the formation of a new
    substance
  • ALWAYS forms a new substance that has different
    physical and chemical properties than the
    original substance.
  • Also known as a chemical reaction.

9
Kinetic Theory
  • All matter is made of tiny particles in constant
    motion.
  • Potential Energy (PE)
  • energy due to the position or condition
  • at the atomic level
  • the distance between the particles
  • closer lower PE farther higher PE
  • Kinetic Energy (KE)
  • energy due to motion
  • Fasterhigher KE slower lower KE

10
  • Based upon particle arrangement
  • Based upon energy of particles
  • Based upon distance between particles
  • AKA POTENTIAL AND KINETIC

11
SOLIDS
  • Particles are tightly packed, vibrating about a
    fixed position
  • definite shape
  • definite volume

Heat
12
LIQUID
  • Particles are tightly packed, but are far enough
    apart to slide over one another
  • indefinite shape
  • a definite volume

Heat
13
GAS
  • Particles are very far apart and move freely
  • indefinite shape
  • indefinite volume

Heat
14
Phases of Matter
State or Phase Particle level picture Particles description Keep Volume? Keep shape?
Solid
Liquid
Gas
  • Arranged in orderly pattern
  • Yes
  • Yes
  • Touching, but not tightly packed
  • No
  • Yes
  • Far apart and rarely touching
  • No
  • No

15
Phases of Matter
State or Phase Particle Movement Amount PE Amount KE Example
Solid
Liquid
Gas
Vibrational only
Low
Very Low
Ice
Vibrational translational
Low
Moderate
Water
High
Vapor
High
Move freely
16
Plasma
  • extraordinary state of matter
  • consists of high energy particles
  • electrons are stripped from their nuclei
  • examples
  • fluorescent light
  • Stars
  • Lightning
  • Most Abundant State of Matter in the Universe!

17
STATES OF MATTER
LIQUID
PLASMA
SOLID
GAS
Tightly packed, in a regular pattern Vibrate, but
do not move from place to place
Close together with no regular arrangement. Vibrat
e, move about, and slide past each other
Well separated with no regular arrangement. Vibrat
e and move freely at high speeds
Has no definite volume or shape and is composed
of electrical charged particles
18
http//www.harcourtschool.com/activity/states_of_m
atter/
ANIMATION
19
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20
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21
Phase Changes Changes of State
  • Adding or removing energy (heat) to a substance
    causes phase changes
  • The potential energy of the particles is
    increased or decreased
  • During a phase change, temperature does NOT change

22
Phase Changes
  • Melting
  • S ? L (adding energy)
  • Freezing
  • L ? S (removing energy)
  • Melting point freezing point of a substance
    occur at the same temperature.

23
Phase Changes
  • Boiling
  • L ? G (adding energy)
  • Evaporation
  • L ? G (adding energy)
  • Condensation
  • G ? L (removing energy)
  • Difference between boiling evaporation
  • Boiling?a specific temp. below the surface
  • Evaporation ?any temp. at the surface

24
Phase Changes
  • Deposition
  • G ? S (removing energy)
  • Examples Snow, frost
  • Sublimation
  • S ? G (adding energy)
  • Examples solid CO2 (dry ice), solid air
    fresheners

25
Phase Change Graphs (T vs t)
Liquid
Melting
Solid
AB -heat ? KE -move faster -temp. ? -solid
BC -heat ? PE -get farther apart -temp. stay
same -melting
CD -heat ? KE -move faster -temp. ? -liquid
26
Phase Change Graph (T vs t)
Gas
Boiling
DE -heat ? PE -get farther apart -temp. stay
same -boiling
EF -heat ? KE -move faster -temp. ? -gas
27
Phase Change Graph (T vs t)
A
C
B
E
D
F
CD -KE ? -slows down -temp. ? -Liquid
AB -KE ? -slows down -temp. ? -Gas
BC -PE ? -closer together -temp. stays
same -Condensation
28
Phase Change Graph (T vs t)
A
B
C
D
E
F
DE -PE ? -closer together -temp. stays
same -Freezing
EF -KE ? -slows down -temp. ? -Solid
29
Phase Change Graph (T vs t)
Boiling Point
Boiling
Freezing
Freezing Point
Melting Point
Melting
What is the boiling point? What is the melting
point? What is the freezing point?
30
Phase Change Graph (T vs t)
If melting freezing points occur at the
same temperature, how do you know which change is
occurring? -depends on whether adding or
removing energy
31
Phase Change Graph (T vs t)
What is this substance? -Water How do you
know? -Boiling melting freezing points of
water (Intensive properties)
32
Energy and Chemical Reactions
  • When a chemical reaction occurs, bonds are formed
    and bonds are broken.
  • If the energy required to form the new bonds is
    greater than the energy of the original bonds,
    the reaction requires the addition of energy and
    is called Endothermic.
  • During an endothermic reaction, the temperature
    decreases. (Heat taken in is changed into bond
    energy.)

33
Energy and Chemical Reactions
  • If the energy required to form the new bonds is
    less than the energy of the original bonds, the
    reaction gives off energy and is called
    Exothermic.
  • During an exothermic reaction, the temperature
    increases. (Bond energy is released in the form
    of heat.)

34
Classification of Matter
Matter
Pure Substances
Mixtures
Elements
Compounds
Homogeneous
Heterogeneous
Solution
Colloid
Suspension
35
Matter
  • Pure Substances
  • made of only one type of matter
  • Mixtures
  • a physical combination of two or more substances
  • no definite ratio of particles
  • Element
  • made of only one type of atom
  • cannot be broken down into simpler substances
    under normal laboratory conditions

36
Matter (contd)
  • Compound
  • Atoms of two or more elements, chemically
    combined in a definite ratio.
  • Homogeneous Mixtures
  • Two or more substances, physically combined in no
    definite ratio.
  • The same throughout.
  • Must be a SOLUTION
  • Heterogeneous Mixture
  • Two or more substances, physically combined in no
    definite ratio.
  • Different throughout
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