Topic 1: States of Matter Flashcards
What are the three states of matter?
Solid
Liquid
Gas
Describe the characteristics of solids.
A solid has a definite volume and shape, which may be affected by changes in temperature.
Solids usually increase slightly in size when heated (expansion) and decrease in size when cooled (contraction)
Describe the characteristics of liquids.
A liquid has a fixed volume and takes the shape of any container into which it is poured.
A liquid’s volume is slightly affected by changes in temperature.
Describe the characteristics of gases.
A gas has neither a definite shape nor a definite volume.
It takes the shape of any container it is placed in and will spread out evenly within it.
The volumes of gases are affected greatly by changes in temperature.
Are solids and liquids compressible?
No
Are gases compressible?
Yes
Describe the kinetic particle theory.
All matter is made up of tiny, moving particles that are invisible. Different substances have different types of particles of varying sizes.
The particles are in constant motion.
Th higher the temperature, the faster the movement on average.
Heavier particles move more slowly than lighter ones at a given temperature.
Describe the structure of solids in terms of the kinetic particle model.
In solids, the particles attract one another.
There are attractive forces between the particles which hold them close together.
The particles have little freedom of movement and can only vibrate about a fixed position.
They are arranged in a regular manner
Describe the structure of liquids in terms of the kinetic particle model.
In a liquid, the particles are still close together but they move around in a random way and often collide with one another.
The forces of attraction between the particles in a liquid are weaker than those in a solid.
The particles have more energy than the ones in the solid state.
Describe the structure of gases in terms of the kinetic particle model.
In a gas, the particles are relatively far apart.
They are free to move anywhere within the container they are in
They move randomly at high speeds, much more rapidly than liquids.
They collide with each other, but less often than in liquids.
They also collide with the walls of the container.
They exert no forces of attraction on each other because they are relatively far apart.
Describe the process of melting.
SOLID ——> LIQUID
When a solid is heated, the particles vibrate faster as they gain energy.
This makes them ‘push’ neighbouring particles away and causes an increase in volume of the solid (expansion)
The heat energy causes the forces of attraction to weaken and the regular pattern of the structure breaks down.
The particles can now move around each other.
This takes place at the melting point of the substance.
The temperature does not rise till all of the solid has melted.
This substance then becomes a liquid.
Describe the process of boiling and evaporation.
LIQUID —–> GAS
The average energy of the particles increases as the liquid is heated.
Some particles at the surface of the liquid have enough energy to overcome the forces and evaporate as a gas.
At the boiling point, particles try to escape form the liquid so quickly that bubbles of gas are formed.
What happens when a gas is cooled?
The particles move closer together and the forces of attraction become more significant.
This results in condensation (GAS —-> LIQUID)
When the liquid is cooled, it freezes to form a solid.
Draw a heating curve.
Draw a cooling curve.
