Chapter 6 🕯 Flashcards
What increases when the volume of a gas decreases?
Pressure
Why does the pressure of gas increase when temperature does?
The molecules move faster so they hit the surface with more force more often
What is the specific latent heat of fusion of a substance?
The energy needed to change the state of 1kg of the substance from solid to liquid
What is the equation for specific latest heat of fusion?
Specific latent heat of fusion = energy / mass
What is latent heat?
The heat taken in or given out by a substance when it changes state
What is the specific latent heat of vaporisation?
The heat needed to change the substance from a liquid at its boiling point to a vapour
What is a substances internal energy?
The energy stores by the particles of a substance
What are the particles like in a solid?
Strong forces of attraction between the particles
Each particle vibrates in a fixed position
When a solid is heated, the particles’ energy stores increase and they vibrate more until they move and the solid melts
What are the particles like in a liquid?
Weaker forces of attraction
These forces of attraction are strong enough to stop the particles completely separating
When a liquid is heated, some particles gain enough energy to beak away from the others and turn into a gas above the liquid
What are the particles like in a gas?
The forces of attraction are very weak
The particles move about quickly and randomly
When heated, the particles gain more energy and so the pressure increase
What is a substances internal energy?
The energy stores by the particles of a substance
What are the particles like in a solid?
Strong forces of attraction between the particles
Each particle vibrates in a fixed position
When a solid is heated, the particles’ energy stores increase and they vibrate more until they move and the solid melts
What are the particles like in a liquid?
Weaker forces of attraction
These forces of attraction are strong enough to stop the particles completely separating
When a liquid is heated, some particles gain enough energy to beak away from the others and turn into a gas above the liquid
What are the particles like in a gas?
The forces of attraction are very weak
The particles move about quickly and randomly
When heated, the particles gain more energy and so the pressure increase
What does the flat section of a temperature-time graph show?
The melting or boiling point of a substance
What is the melting point of a substance?
The temperature at which a solid changes to a liquid
What is the boiling point of a substance?
The temperature at which a liquid changes to a gas
What is the freezing point of a substance?
The temperature at which a liquid changes to a solid
What is a physical change?
A reversible change where no new substances are produced
What is the conservation of mass?
When a substance changes state, the number of particles stays the same
(The mass is conserved when it changes state)
How does the activity of particles change with the states?
Solid: least active
Liquid: quite active as can flow
Gas: very active
What is the equation for density?
Density = mass/volume
How to measure the density of a solid object or liquid?
Measure mass and volume, then use equation d=m/v
What makes an object float on water?
Objects that float on water have a lower density than it (<1000 kg/m^3)
What does the specific heat capacity depend on?
How high you want the temperature
Mass
Substance
What is the specific heat capacity?
The energy needed to raise 1kg of a substance by 1 degree
What is the equation linking energy transfer and specific heat capacity?
Energy transferred = mass x SHC x temperature change
What is the unit for specific heat capacity?
J/Kg°c
How do stars form?
When dust and gas clump together because of gravitational forces
How to calculate mass of liquid
Weigh container before and with liquid
Subtract weight of container from weight with water
Why does the temperature of a gas increase if it is compressed quickly
Work is done but energy isn’t transferred quickly enough to the surroundings
What is internal energy the sum of
The kinetic energy of the particles and the potential energy of the particles
What are convection currents and how are they formed?
Energy is passed from the warm object to the nearby particles by conduction
The air becomes warmer and less dense
The warm air rises and is replaced by cool ar
This cool air is heated too
At the same time, the previously heated air transfers energy to the wsurroundings
It becomes cooler, denser and sinks
The cycle repeats
What is radioactive contamination?
Unwanted presence of materials containing radioactive atoms on other materials
