International Class
Madrasah Mu'allimaat Muhammadiyah Yogyakarta
The Kinetic Particle Model of Matter
States of matter
Chapter 9.1
Matter exists in three states : solid, liquid, and gas
The distinguishing properties of the three states of matter
State | Solid | Liquid | Gas |
Size | rigid, fixed shape, fixed volume, cannot be squashed | not rigid, no fixed shape, fixed volume, cannot be squashed | no rigid, no fixed shape, no fixed volume, can be squashed |
Shape | takes the shape of its container | takes the shape of its container | expands to fill its container |
Chapter 91
Changes of state
Chapter 9.1
evaporation : changing from liquid to a gas at any temperature
boiling : changing from liquid to gas at a fixed temperature called the boiling point
melting : changing from solid to liquid
condensing : changing gas to liquid
solidfying/freezing : changing from liquid to solid
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
The kinetic particle model of matter
related to movement
a model in which matter consist of moving particles
helps to explain the behaviour of materials better
Chapter 9.2
The kinetic theory suggest that :
As particles heat up, they gain more kinetic energy and so move faster
As particles cools down its particles lose kinetic energy and slow down
Chapter 9.2
Absolute zero : the temperature at which particles have no kinetic energy
Chapter 9.2
Arrangement
The particles are packed closely together, in a regular pattern.
The particles are packed slightly less closly together than in a solid.
The particles are no longer in contact unless they collide with each other.
Chapter 9.2
Separation
Each particle is in close contact with all ist neighbours. No separation
The particles are arranged randomly rather than in a fixed pattern (little separation)
The particles are widely separated from one another. In air, the average separation between the particles is about ten times their diameter
Chapter 9.2
Motion
As the particles are so tightly packed, they cannot move around. However, they do move a bit. They can vibrate about a fixed position. The hotter the solid, the more they vibrate
The particles move freely about, bouncing off one another and off the walls of container. In air at room temperature, the average speed of the particles is about 500 m/s and this increases with temperature
As the particles are slightly less tightly packed than in a solid, they can move around. So the particles are both vibrating and moving from place to place. The hotter the liquid is, the faster its molecules move
Chapter 9.2
Attractive forces
Stronges as particles are close together
Moderate as particles are slightly further apart
No force. Particles are far apart
We can also say there are bonds between particle
Chapter 9.2
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
Brownian motion
In 127, a scientist called Robert Brown was using a mocroscope to study pollen grains when he noticed tiny particles jiggling about
At first he thought that they might be alive, but when he repeated his experiment with tiny grains of dust suspended water, he saw that the dust also moved around.
This motion is now known as Brownian motion, and it happens because the moving particles are constantly knocked about by the fast-moving particles of the air
We can do a similar experiment using smoke particles via smoke cell
Chapter 9.2
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
Brownian motion
The dust particles are constantly knocked about by the fast-moving particles of the air
Chapter 9.2
Gases and kinetic model
The kinetic model can help us understand how gases behave, which allows us to answer the following questions :
1
2
3
Why does a gas cause pressure on the walls of its container?
What happens to a gas when it is heated?
What happens when a gas is compressed (squashed)?
Chapter 9.3
1
Why does a gas cause pressure on the walls of its container?
The gas causes pressure on the walls of the container because the gas particles are constantly collinding with the walls
Collide!
Collide!
Chapter 9.3
The higher the temperature of gas, the faster its particles are moving. The particles will hit the walls more often and with more force. This increases the pressure
Collide!
Collide!
2
What happens to a gas when it is heated?
Collide!
Collide!
More faster
Chapter 9.3
3
What happens when a gas is compressed (squashed)?
The volume of container has been decreased. The gas has been compressed into a smaller space. The particles don’t more as far between collisions, so they collide with the walls more often. Decreasing the volume of a gas increases its pressure
Smaller space, collision more likely, therefore higher pressure
Chapter 9.3
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
Temperature and the Celsius scale
Thermal energy transfer from the girl to the thermometer until they are the same temperature
Thermal energy transfer from the thermometer to the ice until they are the same temperature
It occurs because thermal energy has to be transferred to or from the thermometer until is at the same temperature
Chapter 9.4
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
Continued ….
Chapter 9.4
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
The Celsius temperature scale
The melting and boiling points of water are used to define the Celsius temperature scale
The thermometer contains liquid (alcohol, mercury) which expands when it gets hot
Chapter 9.4
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
Continued ….
Steps to calibrate a thermometer
Chapter 9.4
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
Continued ….
Chapter 9.4
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
Kelvin temperature scale
Chapter 9.4
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
Worked example
Continued ….
Calculate the temperature in Kelvin of :
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
Worked example
Continued ….
A laboratory thermometer has no temperature making. Describe how you could use ice melting and boiling water to calibrate the thermometer
Gas laws or Boyle’s law
Note 1 : the gas law refer to a fixed mass of gas
Note 2 : Pressure is caused by the collisions of gas particles and the wall of the container
Chapter 9.5
Pressure and volume
Boyle’s law experiment result. Note that as volume decreases , pressure increases (note : the temperature of gas does no change)
Continued ….
Chapter 9.5
Pressure and volume
There are two graphs to represent the result of a Boyle’s law experiment
The graph of pressure against volume shows that increasing the pressure causes a decreases in the volume
The mathematical relationship between p and 1/V can be seen from this graph. It is a straight line through the origin, which means that pressure in inversely proportional to volume
Continued ….
Chapter 9.5
Pressure and volume
Boyle found out that when he multiplied pressure by volume, he always got the same result
Continued ….
This leads to the following equation that can be used to express Boyle’s law quantitatively
P₁ V₁ = P₂ V₂
The experiment concludes that the volume at a fixed mass of gas is inversely propotional to its pressure, provided its temperature remains constant
Chapter 9.5
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
)
Worked example
Continued ….
A scuba diver releases a bubble of air. The bubble has a volume of 2 cm. He watches it rise to the surface, expanding as it rises. The diver is at a depth where the pressure is 5 atmospheres. What will the volume of bubble be when it reaches the surface, where the volume is 1 atmosphere? Assume that the temperature does not change