Changing State P1 Flashcards
Define density
The ratio of mass to volume in an object
What is the equation linking density, mass and volume?
Density = mass divided by volume
How do you work out the density of an irregular shaped object?
Weigh your object then place it in a eureka can filled with water, measure how much water comes out using a measuring cylinder to work out its volume then do mass divided by volume to get density
What is the kinetic theory of matter for solids?
Particles held together in a fixed regular arrangement by strong forces of attraction and they vibrate about their position. At low temperatures the vibration is small and can be considered fixed but when a solid gains more energy the particles vibrate more causing neighbouring particles to vibrate. Density is highest at this state as particles are closest together
What is the kinetic theory of matter for liquids?
The intermolecular forces within a liquid are too weak to keep particles in a fixed position so although they are close together they can move past each other and form irregular arrangements. Particles have more energy than when solid but less than when gas and move in random directions at low speeds, they flow to fill the shape of a container. Less dense than solids generally
What is the kinetic theory of matter for gases?
The particles are in a random arrangement and in constant motion as there are almost no forces of attraction between them and the particles are free to move and travel in random directions at high speeds, they fill a volume. They have low densities
What is the process of a solid changing to a liquid?
Melting
What is the process of a liquid to a gas?
Evaporation
What is the process of a gas to liquid?
Condensation
What is the process of a liquid to solid?
Freezing
What is the process of a solid to gas?
Sublimation
What is the process of a gas to solid?
Deposition
Define internal energy
The combined energy of a substance’s kinetic and potential energy
What does a change in state cause a change in?
The potential energy of the particles due to their position, the number of particles does not change they are just arranged differently which means mass is conserved
Why does the temperature remain constant when changing state?
Heat energy is being used to break intermolecular bonds between the particles or form bonds between them rather than to raise the temperature
Define specific heat latent
The heat needed to change 1kg of a substance from one state to another without changing its temperature
What is the equation for specific heat latent?
Lf in J/kg = energy divided by mass
What do the air molecules in a smoke cell do?
Air molecules collide with smoke molecules which pushes them and causes them to constantly move and change direction
Define pressure
A force exerted on a surface which can be thought of as force per unit area (m^2)
What is the equation linking pressure force and area?
Pressure = force divided by area