Chapter 1 Solids, Liquids & Gases - World of Chemistry · Chapter 1 Solids, Liquids & Gases 1 ......
Transcript of Chapter 1 Solids, Liquids & Gases - World of Chemistry · Chapter 1 Solids, Liquids & Gases 1 ......
4/26/2010
1
Chapter 1 Solids,
Liquids & Gases
1
Lesson Objectives To describe the main properties of solids, liquids and gases
To describe and explain evidence for movement of particles in liquids and gases
To explain everyday effects of diffusion in terms of particles
To state qualitatively the effect of particle mass on the rate of diffusion
2
What is a matter?
• Can you name me some matter in this room?
Matters are anything that have mass and take up space
3
What are the states of matter?
• How many states are there?
• What are they?
3 states
Solid, Liquid and Gases
4
How many states in this glass ?
Solid
Liquid
Gas
5
Solid Liquid Gas
Hard and dense Not hard butdense
Not dense
Fixed shape No fixed shape No fixed shape
Cannot be compressed
Cannot be compressed
Can be easily compressed
Fixed volume Fixed volume No fixed volume
Do not flow Flow easily Flow in all directions
6
4/26/2010
2
Kinetic Particle Theory
• Matter is any substance that occupies spaceand has mass.
• Matter exists as
7
Matter are made up of tiny particles:
1. These particles are too small to be seen
2. There are spaces between the particles
3. Particles are in constant motion
Kinetic particle theory of Matter:Matter are made up of particles and these particles are too small to be seen directly There are spaces between the particles Particles are in constant motion
Diffusion:Diffusion is the spreading and mixing (movement) of particles in liquids and gases The higher the temperature, the faster the molecules move, the faster is the diffusion.The smaller the mass, the faster they move, the higher the rate of diffusion.
Summary
8
9
Particulate
Model of Matter
Lesson Objectives To describe the kinetic particle model of solids, liquids and gases
To use particulate model to explain the behavior and properties of matter
To explain the interconversion of states of matter in terms of the kinetic theory and of the energy changes involved
10
Solid• Arrangement
– Orderly
– Closely packed
• Forces between particles– Very strong
• Particle Kinetic Energy– Very Low
• Particle motion– Vibrate and rotate about a fixed
position
11
Liquid• Arrangement
– Disorderly
– Less closely packed
• Forces between particles– Strong
• Particle Kinetic Energy– Low
• Particle motion– Slide over each other
12
4/26/2010
3
Gas• Arrangement
– Disorderly
– Very far apart
• Forces between particles– Very weak
• Particle Kinetic Energy– High
• Particle motion– Move around at high speed
13
Having the physical properties in mind, what will you think the arrangement and movement of particles will be?
14
Solid Liquid Gas
Drawing the particulate diagram for different states
15
Density
• Look at the particle models again…
• Which state has highest density?
Solid (ice) Liquid (coke) Gas (carbon dioxide)
Density Highest Mid range Lowest
Liquid has fewer particles than an equal volume of solid, similarly gas has fewer particles and the particles are further apart than the particles in the same volume of liquid or solid. Therefore density of gas (mass per volume) is lowest.
16
Solid Liquid Gas
Can you see the difference?
Particle diagram
17
Particles in a solid – animation
18
4/26/2010
4
Particles in a liquid – animation
19
Particles in a gas – animation
20
Solid Liquid Gas
Arrangementof the particles
Particles are very closely packed together in an
orderly manner
Particles are closely packed together in a
disorderly manner
Particles are far apart in
randomarrangement
Quick review
Particulate Theory of Matter
21
Solid Liquid Gas
Attractive
Forces
Particles held together by
strong forces
Held together by strong forces
(weaker than
that of solid)
Not held together by
strong forces
Solid Liquid Gas
Movement of the
particles
Vibrations about fixed positions
Randommovement
throughout the liquid
Movement anywhere
Attractive Forces
22
Next lesson…
23
• Please read textbook pg 44-49 – Changes of states.24
4/26/2010
5
Solid Liquid Gas
Drawing the particulate diagram for different states
25 26
Changes of
State…
Change of states
Boiling
Condensation
Lesson Objectives
To observe the differences in the changes between the 3 states of matter
To use particulate model to explain the changes of matter
To explain the interconversion of states of matter in terms of the kinetic theory and of the energy changes involved
28
Changes of states
• Particulate model of matter can explain the changes of state.
• What happen when a solid is heated?
Let view the animation…
Melting• When a solid is heated…
Particles in it gain energy and vibrate more.
As temperature increases, vibrations increases until they are able to overcome the forces that hold them in their fixed positions.
The temperature at which a solid melts is called the melting point.
The temperature remains constant at the melting point because the heat absorbed is used to overcome the attractive forces between the particles.
30
4/26/2010
6
Boiling• When a liquid is heated…
Particles in it gain energy.
As temperature increases, particles move more quickly and eventually have enough energy to completely break the forces that hold them together.
Particles then move freely and far apart.
The temperature at which a liquid boils is called the boiling point.
There is no change in the temperature at this point.
• The temperature is constant because heat absorbed is used to break all the forces holding the particles together.
31
Change of states
http://www.footprints-science.co.uk/flash/states.swf
Heating Curve
A
B
C
D E
Mixture of solid and liquid
Mixture of liquid
and gas
Reading the Heating Curve 1
Graph shows how temperature of substance changes with time during
melting when it is heated steadily.
1. AB - the substance is completely ______________.
2. Point B - ____________ begins at _______________________.
( The first drop of ________ appears).
3. BC - ________ continues to take place. The substance
exists as a ________ of _____ and __________.
4. Point C – The last drop of _________ is formed.
5. CD – The substance is completely __________
( )
melting
solid liquid
liquid
molten
liquid
liquid
mixture
solid
melting
the melting point
Think……
Why does the temperature remain constantbetween B and C even though heat is continuously supplied?
Ans: The heat is used to overcome the forces of attraction holding the solid particles instead of causing the temperature to rise.
Reading the heating curve 2
Graph shows how temperature of substance changes with time during
melting when it is heated steadily.
1. CD - the substance is completely ______________.
2. Point D - ____________ begins at _____________________.
( The first drop of ________ appears).
3. DE - ________ continues to take place. The substance
exists as a ________ of _____ and __________.
4. Point E – The last drop of ________change into
_________ state.
5. Beyond E – The substance is completely __________
liquid
boiling the boiling point
gas
boiling
mixture gas liquid
liquid
gaseous
gaseous
4/26/2010
7
Condensation• When a gas is cooled…
Particles in it loses energy; move more slowly.
The forces of attraction between the particles will pull the particles closer to each other, eventually forming a liquid.
37
Freezing• When a liquid is cooled…
Particles in it loses energy; move more slowly.
Temperature decreases until freezing point is reached.
At freezing point, the liquid turns into a solid.
Temperature stay constant while liquid freezes because heat energy is released when particles slowed down to take up their fixed positions in the solid.
38
Cooling Curve
temperature remains constant
freezing completes
freezing starts
freezing point
(=melting point)
SOLID
LIQUID + SOLID
LIQUID
temperature (ºC)
time from start (min)
P
Q R
S
Reading a graph on freezing
Graph shows how temperature of substance changes with time during
melting when it is heated steadily.
1. PQ - the substance is completely ______________.
2. Point Q - ____________ begins at _____________________.
( The ______ drop of liquid begins to form a ______).
3. QR - ________ continues to take place. The substance
exists as a ________ of _____ and __________.
4. Point R – The last drop of _________ will change into a ______
5. RS – The substance is completely __________
liquid
solid
the freezing point
first
freezing
freezing
mixture liquidsolid
liquid solid
solid
Think……..
Why does the temperature remain constantbetween QR even though the substance is continuously cooled?
Ans:
During cooling heat is given out by particles as they take up fixed positions is equal to heat loss from the surround during cooling.
Sublimation• When solids change into gases without melting.
Examples:
- Solid carbon dioxide changes to a gas at -78°C
- Iodine
- Ammonium chloride
42
4/26/2010
8
Evaporation• When liquids turn into gases without boiling.
• Evaporation occurs below boiling point of liquid.
Difference between boiling and evaporation?
Evaporation only takes place at the surface of liquid, at any temperature and is very slow.
Boiling takes place throughout the liquid, only at boiling point and is usually faster.
43 44
Practice Question Practice Questions