Paper 1 - Topic 3, Particle Model Of Matter Flashcards
What are chemical changes
Changes to the structure of a substance, the substance does not usually restore its original properties when the changes are reveresed
What is condensation
The changing from vapour state to a liquid state when a substance is cooled
What is 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 is freezing
The changing from a liquid state to a solid state when a substance is cooled
What is the temperature of gas directly proportional to
The average kinetic energy of its molecules
What is internal energy
The energy stored by the atoms and molecules that make up a system, it is equal to the same of the total kinetic and potential energies of the particles in the system
What is latent heat
The energy required for a substance to change state
What is melting
The changing from a solid state to liquid state when a substance is heated
What is the unit for pressure
Pascals
What are physical changes
Changes to the physical properties of a substance which can be reversed, changes of state are physical changes as they can restore their original properties
What is pressure
The force acting perpendicular to a surface
What is specific heat capacity
The amount of energy needed to heat 1kg of a substance by 1 degrees Celsius
What is sublimation
The direct changing of a substance from a solid state to a vapour state without passing through the liquid phase
Describe gases
- most kinetic energy
- particles can move freely
- lowest density
Describe solids
- particles can only vibrate in fixed places
- highest density
- least amount of kinetic energy
Describe liquids
The particles can flow over each other and the particles are close together with an irregular arrangement
What always stays the same in changes of state
The mass
What does temperature increase depend on in specific heat capacity
- material type
- material mass
- energy inputted
What happens when work is done on a gas
Energy is transferred to it
What is temperature determined by in particles
The amount of kinetic energy of the substance, the higher the temperature, the higher the kinetic energy
What does density depend on
The spacing of the atoms in matter
What happens when you heat a system
- heating increases the energy the particles have
- this increases internal energy
- this either raises the temperature of the system or produces a change in state
How does changing the volume of a gas affect the pressure
Increasing the volume in which a gas is contained (at a constant temp) can lead to a decrease in pressure this is due to the reduced number of collisions per unit area
