Download - CHAPTER 2: SOLIDS, LIQUIDS AND GASES
CHAPTER 2: SOLIDS, LIQUIDS AND GASES
water
rock
air sand
lava
woodoil
What is our world made of ?
liquid
solid
gas
solid liquid gas
1.States of Matter
Properties of Solids
• Definite shape• Definite volume• Hard to compress• Do not flow
Types of solids• Solids that are made up of crystals are
called crystalline solids. • I.e.: salt, sugar, snow…• Amorphous solids:The particles are
not arranged in a regular pattern. • They don’t melt at a distinct
temperature, they may become softer or change into other substances.
• I.e.: plastics, rubber and glass
• The pictures below show the arrangement of solid particles
• Please identify the types of solid.
Properties of Liquids
• No definite shape• Definite volume• Flow easily• Hard to compress
Properties of liquids• Surface tension is the result of an inward pull
among the molecules of a liquid that brings the molecules on the surface closer together.
• Fluid : a substance that flows• Another property of liquids is viscosity .• Viscosity depends on the size and shape of
its particles and the attraction between the particles.
Properties of Gases
• No definite shape• No definite volume• Easy to compress• Spread out to fill all available
space - diffusion
Change of State
Energy
2. Change of State Changes Between Solid and Liquid• The temperature at which the solid melts – melting
point
Vibrating a little
Particles vibrate more
Solid melted to form liquid
o The melting point is the temperature at which the solid and liquid states of a substance exist together
Changes Between Liquid and Gas
Particles in liquid state
Particles move faster
Particles have enough energy to escape
The boiling point is the temperature at which evaporation begins to occur throughout the liquid, i.e. Bubbles of vapour form inside the liquid
Temperature Scale For Water
Change of State - Evaporation
What happens if there are puddles on the road on a sunny day?
Sun gives some particles near surface extra energy
Particles have enough energy to overcome forces holding them together
Break away from liquid & go into the air
Some liquid has evaporated to form a gas
o Evaporation is the changing of a liquid to a vapour that take place only on the surface of a liquid.
Vaporization: The change from a liquid to a gas
Vaporization Evaporation
Boiling
Question
What are the ideal conditions when hanging out clothes to dry?
Dry, warm and windy
Evaporation is helped by the wind
The wind blows away the particles that have already evaporated
This makes room for more particles to evaporate
Evaporation V Boiling Point Liquid doesn’t have to be heated
to its boiling point for evaporation to occur – evaporation from surface of liquid is always taking place
Condensation• When gas cooled.• Particles slow down, become closer to
each other.• Liquid formed eventually.
Changes from the Gas to the Liquid:
Condensation
Questions On a cold morning if
you breath on the window of the car what happens?
What happens to the mirror in the bath room when you have a hot shower?
Why do they happen?
Why does butter spread more easily if it is warmed slightly?
Why do ice cubes added to a glass of lemonade slowly disappear?
Condensation Steam (gas)
cooled when it hits the cold mirror
Particles slow down, become closer to each other
Liquid formed eventually
Math Analyzing Data P53 1.Time on the x-axis, temperature on
the y-axis. 2.The temperature is rising from 0 ℃ to
100 ℃ 3. Segment B: melting point of ice; Segment D: boiling point of water 4. Melting and Boiling 5.Water molecules in segment E have
more thermal energy because they are at a higher temperature.
Sublimation• Some substances when heated change
directly from solid to gas (sublimation)
• Iodine and solid carbon dioxide (dry ice)
Changes Between Solid and Gas:
Solid Liquid Gas
Particle Arrangement
3.GAS BEHAVIOUR• When working with a gas, it is helpful to know its
volume, temperature and pressure– Volume: amount of space that matter fills
(cm3, ml or L)– Temperature: measure of the average energy of
random motion of the particles of a substance. The faster the particles are moving, greater energy and higher temperature.
– Pressure: (particles collide with one another and with the walls of their container). Force of its outward push divided by the area of the walls of the container• Pressure= Force/Area Unit: Pascal (Pa), atmosphere
(atm), mmHg (millimeters of Mercury)
1. PRESSURE AND VOLUME– Boyle’s law
• When the pressure of a gas at constant temperature is increased, the volume of the gas decreases. When the pressure is decreased, the volume increases.
• Relationship between volume and pressure– I.e.: Balloons in the
atmosphere and bicycle pump
– Pressure and volume graph
2. PRESSURE AND TEMPERATURE– When the temperature of a gas at constant
volume is increased, the pressure of the gas increases. And the opposite.• I.e.: Trucks tires in summer (reduce the pressure)• Pressure and temperature graph
3. VOLUME AND TEMPERATURE– Charles’s Law
• When the temperature of a gas is increased at constant pressure, its volume increases. When the temperature of a gas is decreased at constant pressure, its volume decreases
• I.e.: Balloon in the oven and freezer• Volume and temperature graph