Particles Flashcards
Explain what density is
What is the equation for density
Density is the mass per unit volume of a substance. This means it tells us how packed together the particles are
The equation for density is:
density = mass/volume
density is measured in kg/m3
mass is measured in kg
volume is measured in m3
How do you calculate the volume of a regular solid and use this to find the density?
To find the volume of a regular solid you need to measure the length, breadth and depth and multiply them together.
Then you find the mass on a set of mass scales and find the density by using the formula density = mass/volume
How do you measure the volume of an irregular solid and use this to find the density of the object?
To find the density of an irregular object you need to use a displacement can. You fill the can with water, drop the object into the water and measure the volume of water that comes out of the can.
You then measure the mass on a mass balance and use the equation density = mass/volume to find the density of the object.
What are the properties of a solid
Fixed shape
Dense
Cannot be compressed
Hard
What are the properties of a liquid?
Can flow
Takes the shape of its container
Dense
Cannot be compressed
What are the properties of a gas?
Can flow
Low density
Takes the shape of its container
Easily compressed
What are the changes of state labelled A-F in this diagram
A = Freezing
B = Melting
C = condensing
D = Evaporating/boiling
E = Deposition
F = Sublimation
How are the particles arranged in a solid?
How do the particles relate to its properties?
The particles in a solid are arranged close together in a regular order and are attached by strong bonds
Solids cannot flow becuase the particles are held together by the bonds between them. It is dense becuase the particles are all touching.
How are the particles arrange in a liquid?
How does the particle arrangement relate to it’s function?
The particles in a liquid are arranged in an irregular pattern but they are still touching. They are held together by weak intermolecular bonds.
Becuase the particles can move past each other, a liquid can flow and take the shape of its container. It is dense and cannot be easily compressed because the particles are close together
How are the particles arranged in a gas?
Explain how the particle arrangment of a gas relates to its properties
The particles in a gas are arranged so that they are randomly placed and are very far apart
A gas can flow becuase the particles can move past each other, this means it also takes the shape of its container. Gasses are not dense because there are spaces between the particles and can be easiliy compressed becuase these spaces can be made smaller
What is internal energy?
|nternal energy is the total energy of the particles of a substance
Define the term ‘melting point’
Melting point is the temperature at which a substance changes state between a solid and a liquid. If the temperature is above the melting point it is a liquid, and if the temperature is below the meltion point it is a solid.
Define the term ‘boiling point’
The boiling point is the temperature that the substance changes from a liquid to a gas. When a substance is below the boiling point it is a liquid and when it is above the boiling point it is a gas
What is ‘latent heat’?
How do you calculate the latent heat of a substance when it changes state?
Latent heat is the energy required to change state. While something is changing state it does not change its temperature. This is becuase the energy is transferring into or away form the internal potential energy store and not the internal kinetic energy store.
To calculate the latent heat you use this formula:
E = mL
E = energy (latent heat) (J - Joules)
m = mass (kg - kilograms)
L = specific latent heat (J/kg - Joules per kilogram)
There are two different types of latent heat. If something is melting or freezing you need to use the specific latent heat of fusion. If something is boiling or condensing you need to use the specific latent heat of vaporisation
What happens to the internal energy of a substance when it is heated?
When a substance is heated the internal energy increases.