Topic 3 Flashcards
What are Properties of Solids?
Strong forces of Attraction
Particles don’t have much energy to vibrate
In fixed positions
A regular arrangement
What are Properties of Liquids?
Weaker forces of attraction
Moves in random directions
Have more energy than Solids
Can move past each other
What are the properties of Gases?
No forces of Attraction Free to move Far apart More energy than liquids & solids Move in random directions and Speeds
What do colliding gas particles cause?
Pressure
What is Pressure?
It is the force exerted per unit.
So in a sealed container the outward gas pressure is what?
The total force exerted by all of the particles in a gas on a unit area of the container walls.
How can you increase pressure?
By increasing the number of collisions per second by increasing Temperature.
Decreasing the temperature of a gas decreases what and why?
When their is a lower temperature particles have lower Kinetic energy which means that their are fewer collisions per second, meaning their are fewer energy collisions, decreasing pressure.
Increasing the temperature of a gas increases what and why?
When their is a Higher temperature particles have Higher Kinetic energy which means that their are more collisions per second, meaning their are Higher energy collisions, this increases the pressure.
Nadia is investigating how the pressure of a gas is affected by its temperature. She places a balloon into a freezer for one hour.When she took it out of the freezer, she noticed that its volume had decreased. She then set it on a table. After a few minutes, it had returned to its original size, as shown below. Using ideas about particles and pressure, explain why the volume of the
balloon had decreased when it was taken out of the freezer.
The moment the balloon was placed into the freezer, the air inside it would have been at a higher temperature than the air inside the freezer
This would have caused thermal (heat) energy to flow from the air in
the balloon to the air in the freezer and the temperature of the air inside
the balloon would have decreased (until it had reached the operating
temperature of the freezer) [1].
This means that the kinetic energy of the air particles inside the balloon
would have decreased [1]. As the particles would then have been moving
more slowly, the amount of pressure they would exert on the inside
surface of the balloon would decrease (they would strike the inside
surface less frequently, and with less force each time they did so) [1].
What is Density?
Is a measure of the compactness of a substance which tells you the mass of a given volume.
What is the equation for Density?
Density(Kg/m 3)=Mass(Kg)/Volume(m 3)
What does density depend on?
What it is made of and how its particles are arranged.
What is a dense material?
has its particles packed tightly together.
Why are solids dense?
Because the particles are packed close together and solids have a lot of mass
Does a brick a high or low density and why?
The brick has a high density. It has lots of mass packed into his volume.
Does a Polystyrene block have a high or low density?
It has a low density. It has a lower mass packed into its volume.
Do gases have a low or high density?
Low density, the particles are far apart so gases only have a small mass for their volume
Polystyrene is a solid so why does it have a low density?
it has a very open structure and it is full of air spaces, it has a small mass for its volume.