Knowt
Changing State
Substances can change from one state to another
Physical changes don’t change the particles-just their arrangement or their energy
When a solid is heated, its particles gain more energy
This makes the particles vibrate more, which weakens the forces that hold the solid together
At a certain temperature, called the melting point the particles have enough energy to break free from their positions, called melting and turns a solid to an liquid
When a liquid is heated, again the particles get even more energy
This energy makes the particles move faster, which weakens and breaks the bonds holding the liquid together
At a certain temperature, called the boiling point, the particles have enough to break their bonds
This is evaporating, and the liquid becomes a gas
As a gas cools, the particles no longer have enough energy to overcome the forces of attraction between them
Bonds form between the particles
At the boiling point, so many bonds have formed between the gas particles that the gas becomes a liquid, this is called condensing
When a liquid cools, the particles have less energy so move around less
There’s not enough energy to overcome the attraction between the particles, so more bonds form between them
At the melting point, so many bonds have formed between the particles that they’re held in place
The liquid becomes a solid and this is called freezing
Heating up
Melting - When a solid is heated, it absorbs energy and it melts, turning into a liquid.
Boiling - If the liquid is heated, it absorbs more energy and it boils, turning into a gas.
These changes absorb energy from the surroundings so they are endothermic.
Evaporating is when a liquid turns into a gas slowly, at temperatures that are below its boiling point. Puddles dry up because they evaporate – they don’t boil.
Cooling down
Condensing - If a gas is cooled, it transfers energy to the surroundings, and turns into a liquid.
Freezing - If the liquid is cooled, it transfers energy to the surroundings, and turns into a solid.
These changes transfer energy to the surroundings so they are exothermic.
Changing State
Substances can change from one state to another
Physical changes don’t change the particles-just their arrangement or their energy
When a solid is heated, its particles gain more energy
This makes the particles vibrate more, which weakens the forces that hold the solid together
At a certain temperature, called the melting point the particles have enough energy to break free from their positions, called melting and turns a solid to an liquid
When a liquid is heated, again the particles get even more energy
This energy makes the particles move faster, which weakens and breaks the bonds holding the liquid together
At a certain temperature, called the boiling point, the particles have enough to break their bonds
This is evaporating, and the liquid becomes a gas
As a gas cools, the particles no longer have enough energy to overcome the forces of attraction between them
Bonds form between the particles
At the boiling point, so many bonds have formed between the gas particles that the gas becomes a liquid, this is called condensing
When a liquid cools, the particles have less energy so move around less
There’s not enough energy to overcome the attraction between the particles, so more bonds form between them
At the melting point, so many bonds have formed between the particles that they’re held in place
The liquid becomes a solid and this is called freezing
Heating up
Melting - When a solid is heated, it absorbs energy and it melts, turning into a liquid.
Boiling - If the liquid is heated, it absorbs more energy and it boils, turning into a gas.
These changes absorb energy from the surroundings so they are endothermic.
Evaporating is when a liquid turns into a gas slowly, at temperatures that are below its boiling point. Puddles dry up because they evaporate – they don’t boil.
Cooling down
Condensing - If a gas is cooled, it transfers energy to the surroundings, and turns into a liquid.
Freezing - If the liquid is cooled, it transfers energy to the surroundings, and turns into a solid.
These changes transfer energy to the surroundings so they are exothermic.