TOPIC 3 Cooling + Heating and Cooling curves + states of matter Flashcards
The temperature of the liquid in the container decreases as the liquid evaporates. Use kinetic theory to explain why
The particles with the most energy are able to break the bonds holding them in place and leave the surface of the liquid, taking the energy with them.
This causes the internal energy of the remaining particles to decrease leading to a decrease in temperature
(evaporation by cooling)
vaporisation = evaporation
Explain how the windows in a bus full of people mist up
or what happens when water vapour condenses on a cold surface
Condensation
When the particles in a vapour, make contact with the cold surface, the particles transfer heat energy to the cold surface by conduction.
The internal energy of the vapour particles decreases, causing them to come together
The vapour will therefore turn from a gaseous state to a liquid
How can the process of evaporation be sped up
Increasing the surface area of the liquid
Creating a draft of air across the surface of the liquid. (blowing across the air)
Explain how increasing the surface area of a liquid speeds up the process of evaporation
If the surface area is increased, then a greater amount is of liquid (particles) will be exposed to the air is larger. Therefore more particles can leave the surface of the liquid
Explain how creating a draft of air across the surface of the liquid speeds up the process of evaporation
By creating a draft of air across the surface of the liquid, particles will be carried away from the surface of the liquid.
What are the three states of matter
Solid, liquid, gas
Which of the three states of matter can flow
Solid - cannot flow
Liquid - can flow
Gas - can flow
Describe the shape of the three states of matter
Solid - fixed
Liquid - fits the container shape
Gas - fills the container
Describe the volume of the three states of matter
Solid - fixed
Liquid - fixed
Gas - can be changed (can compress gases)
Describe the density of the three states of matter
Solid - much higher than a gas
Liquid - much higher than a gas
Gas - low compared with a solid or liquid
Complete the sentence
When water in a kettle boils, the water turns to _________
When solid carbon dioxide or ‘dry ice’ warms up, the solid turns into a _____ directly
When steam touches a cold surface, the steam ______ and turns to ______
When water in a kettle boils, the water turns to steam
When solid carbon dioxide or ‘dry ice’ warms up, the solid turns into a gas directly
When steam touches a cold surface, the steam condenses and turns to water
What is another name for steam
Steak a.k.a. water vapour
What is steam
Steam is water in its gaseous state
State the changes of state
Melting
Freezing (or solidifying)
Sublimation
Boiling
Condensation
State the processes of the changes of state
Melting - Solid to Liquid
Freezing - Liquid to Solid
Sublimation - Solid to Gas
Boiling - Liquid to Gas
Condensation - Gas to Liquid, Gas to Solid
What are melting, boiling and condensation examples of
Melting, boiling and condensing are examples of physical changes (same substance, just arranged differently)
Complete the sentence
When the temperature of the substance is increased, the particles _______
When the temperature of the substance is increased, the particles move faster
Describe the kinetic theory of matter of a solid
The particles in a solid are held next to each other in fixed positions. They vibrate about their fixed positions, so the solid keeps its own shape
Describe the kinetic theory of matter of a liquid
The particles in a liquid are in contact with each other.
They move about at random.
So a liquid does not have its own shape and it can flow.
Describe the kinetic theory of matter of a gas
The particles in a gas move about at random much faster than they do in a liquid.
They are, on average, much further apart from each other than the particles of in a liquid. So the density of a gas is much less than that of a solid or a liquid.
The particles in solids, liquids and gases have different amounts of energy.
The particles in a gas have _________ than those in a liquid, which have more ______ than those in a solid
The particles in solids, liquids and gases have different amounts of energy.
The particles in a gas have more energy than those in a liquid, which have more energy than those in a gas
Why are changes of state examples of physical changes?
Changes of state are examples of physical changes because no new substances are produced.
Explain in detail why 1kg of a solid has a smaller volume than 1kg of a gas (4 marks)
Explain in detail why 1kg of a gas has a much larger volume than 1kg of a solid
Use kinetic theory to explain why.
The particles in a solid are much closer together than a gas
This is due to:
The bonds between the particles are stronger
The particles in a solid have less energy
The particles in a solid do not move but vibrate in a fixed position
Draw a heating and cooling curve
file:///C:/Users/44748/Documents/heating%20and%20cooling%20graphs,%20heating%20and%20cooling%20curves.pdf
Describe what is happening at A - on a heating curve
file:///C:/Users/44748/Documents/heating%20and%20cooling%20graphs,%20heating%20and%20cooling%20curves.pdf
The heat energy is increasing the temperature of the solid, but it is not melting
Describe what is happening at B - on a heating curve
file:///C:/Users/44748/Documents/heating%20and%20cooling%20graphs,%20heating%20and%20cooling%20curves.pdf
The heat energy is used to increase the energy of the particles, the bonds between the particles will break, turning the solid into a liquid
Describe what is happening at C - on a heating curve
file:///C:/Users/44748/Documents/heating%20and%20cooling%20graphs,%20heating%20and%20cooling%20curves.pdf
All of the solid has now melted and the heat energy supplied causes an increase in the temperature of the liquid.
Describe what is happening at D - on a heating curve
file:///C:/Users/44748/Documents/heating%20and%20cooling%20graphs,%20heating%20and%20cooling%20curves.pdf
The heat energy is used to increase the energy of the particles, the bonds between the particles will break, turning the liquid into a gas or vapour.
Describe what is happening at E - on a heating curve
file:///C:/Users/44748/Documents/heating%20and%20cooling%20graphs,%20heating%20and%20cooling%20curves.pdf
All the liquid has now boiled and the heat energy supplied causes an increase in the temperature of the gas
Describe what is happening at E- on a cooling curve
file:///C:/Users/44748/Documents/heating%20and%20cooling%20graphs,%20heating%20and%20cooling%20curves.pdf
The heat energy released is decreasing the temperature of the gas, but it is not condensing.
Describe what is happening at D - on a cooling curve
file:///C:/Users/44748/Documents/heating%20and%20cooling%20graphs,%20heating%20and%20cooling%20curves.pdf
The heat energy released decreases the energy of the particles, the bonds between the particles will form, turning the gas into a liquid
Describe what is happening at C - on a cooling curve
file:///C:/Users/44748/Documents/heating%20and%20cooling%20graphs,%20heating%20and%20cooling%20curves.pdf
All the gas has now condensed and the heat energy released causes a decrease in the temperature of the liquid.
Describe what is happening at B - on a cooling curve
file:///C:/Users/44748/Documents/heating%20and%20cooling%20graphs,%20heating%20and%20cooling%20curves.pdf
The heat energy released decreases the energy of the particles, the bonds between the particles will form, turning the liquid into a solid.
Describe what is happening at A - on a cooling curve
file:///C:/Users/44748/Documents/heating%20and%20cooling%20graphs,%20heating%20and%20cooling%20curves.pdf
All the liquid is now frozen and the heat energy released causes a decrease in the temperature of the solid
