Topic 3 : Particle Model of Matter Flashcards
What does the phrase ‘change in thermal energy’ mean?
A temperature dependent component, whose resistance increases
as its temperature decreases.
What does chemical changes mean?
A temperature dependent component, whose resistance increases
as its temperature decreases.
What does condensation mean?
A temperature dependent component, whose resistance increases
as its temperature decreases.
What is the definition of density?
The mass per unit volume of an object.
What is evaporation?
The changing from liquid state to a vapour state, when a substance is heated.
What does freezing mean?
The changing from a liquid state to a solid state, when a substance is cooled.
What does gas temperature mean?
The temperature of a gas is directly proportional to the average kinetic energy of it’s molecules.
What is the definition of internal energy?
The energy stored by the atoms and molecule that make up a system. It is equal to the sum of the total kinetic and potential energies of the particles in the system.
Define latent heat?
The energy required for a substance to change state?
What does melting mean?
The changing from solid state to liquid state, when a substance is heated.
What does Pascals mean?
The unit of pressure, equal to a force of one Newton acting perpendicular to an area of one metre squared.
What are physical changes?
Changes to the physical properties of a substance which can be reversed. Changes of state are physical changes since substances can restore their original properties when the changes are reversed.
What does pressure mean?
The force acting perpendicular to a surface, per unit area.
What is specific heat capacity?
The amount of energy needed to increase the temperature of one kg of a given substance by one degree Celsius.
What does specific latent heat of fusion mean?
The amount of energy needed to change the state of one kg of a substance from solid state to liquid state, whilst held at a constant temperature.
What is specific latent heat of vaporisation?
The amount of energy needed to change the state of one kg of a substance from liquid state to vapour state, whilst held at constant temperature.
What is specific laten heat?
The amount of energy needed to change the state of one kg of a substance, whilst held at constant temperature.
What is sublimation?
The direct changing of a substance from a solid state to a vapour state, without passing through the liquid phase.
What is always conserved when a substance undergoes a change of state?
It is mass.
How does a change of state differ from a chemical change?
In a change of state, the material can return to having its previous properties if the change is reversed.
Describe the force that the pressure of a gas exerts on the walls of it’s container?
- The net force acts at right angles to the containers surface
- The force increases as pressure increases
