P6 Molecules and matter Flashcards
Density equation, P(Kg/m^3)
density(kg/m^3) = mass, m(kg)/volume, v(m^3)
Specific Latent heat equation
Energy = Mass x Latent Heat
What happens if something is less dense than water?
It floats and vice versa.
What is an example of a physical change?
A change in state as no new substances are produced. If is is reversed the substances recovers its original properties.
What is conservation of mass?
It is the mass of substances being conserved when it changes state.
What is latent heat?
The energy transferred to a substance when it changes its state. The temperature does not change at the substances melting or boiling point.
What is needed to melt a solid or boil a liquid?
Energy through a liquid at its boiling point. Evaporation occurs from the surface when the temperature is below its boiling point.
What is internal energy?
The energy stored by the particles of a substance. It is the energy of the particles caused by their individual motion and positions.
What is internal energy the sum of?
The kinetic energy they have due to individual motions and the potential energy they have due to their individual positions relative to each other.
What determines if
a substance is a solid, liquid or gas?
The strength of the forces of attraction between the particles of a substance.
What is latent heat of fusion?
The energy needed to change the state of 1kg of a substance from a solid to a liquid.
What is latent heat of vaporisation?
The energy needed to change the state of 1kg of a substance from a liquid to a vapour.
Why does increasing the temperature of any sealed gas container increase the pressure of the gas inside it?
The energy transferred to the gas when its heated increases the kinetic energy of the molecules. The average speed of the molecules also increases when the kinetic energy increases as the molecules hit the container surfaces with more force and more often.
What is the rule for a fixed mass of gas at constant temperature?
Its pressure is increased if its volume is decreased. Reducing the volume of a gas increases the number of molecular impacts on the surfaces in contact with the gas.
What is the equation for Boyles law?
pressure(Pa) x volume(m^3) = constant
