P1.2 & P1.3 Flashcards
What is internal energy?
Internal energy is the total amount of kinetic and potential energy of all the particles that make up a system.
Does temperature change during state changes? Why?
No, the energy goes into the breaking the forces between particles increasing the temperature.
formula for specific heat capacity
Change in thermal energy = mass x specific heat capacity x temperature change
What is specific heat capacity?
the energy required to raise the temperature of one kilogram of a substance by one degree Celsius
gas to solid
deposition
solid to gas
sublimation
gas to liquid
condensation
liquid to gas
boiling
liquid to solid
freezing
What is temperature?
Temperature is the average amount of kinetic energy between the particles.
What happens to the mass during a stage change?
Mass is conserved.
A change in the temperature of a system depends on:
the mass of the material
the substance of the material
the amount of energy put into the system
Why is it easier to heat up lead rather than a liquid?
Since lead is a solid and the particles are only vibrating, they vibrate faster after being heated. As the particles are closer together in a solid, they are more likely to hit each other and pass the energy around.
This means that the energy spreads through the block quickly and the temperature of the block goes up quickly.
Specific Latent Heat
Amount of energy needed to change the state of 1 kilo of a substance WITHOUT a change in temperature.
specific latent heat of vaporization
The amount of energy required to change a unit mass of a substance from liquid to gas
Specific latent heat of fusion
the energy needed to change a unit mass from the solid to the liquid phase at constant temperature
conservation of mass
a principle stating that mass cannot be created or destroyed.
internal energy
the sum of the kinetic and potential energies of all particles in the system
heat = increase in internal energy
cool = reduce internal energy
specific latent heat formula
Energy = mass(kg) x specific latent heat
What happens when a hot object is touching a cold one?
Thermal energy is transferred between the two objects. When both are at the same temperature there is no further exchange of thermal energy.
latent heat graph
In the graph there are flat spots which represent the change in state (breaking/forming intermolecular bonds)
Higher SHC meaning
takes more energy to increase temperature.
SHC =
Energy / Mass X Temperature
2 ways to heat up a gas
- Do work to it (eg. reduce volume)
- Heat it up
pressure in a gas?
caused by the random movement of particles hitting the walls of the container.
reasons by balloon get bigger?
we blow into them meaning
more air particles
more collisions —> more higher overall force —-> higher pressure
increasing the temperature of a gas with a sealed container?
increase kinetic energy —> increases internal energy
smaller volume =
bigger pressure
This is when:
pressure (p) is measured in
force (F) is measured in
area (A) is measured in
This is when:
pressure (p) is measured in pascals (Pa)
force (F) is measured in newtons (N)
area (A) is measured in metres squared (m2)
When a gas is compressed:
- Area decreases
- Force increases
- Pressure increases
- No collisions increases
- Volume decreases
What does Boyle’s law state?
states that pressure is inversely proportional to volume
Boyle’s Law formula
P1 x V1 = P2 x V2 OR pV = k
P = pressure measured in
V = volume measured in
C = constant is a number in
P = pressure measured in Pascals (Pa)
V = volume measured in m^3
C = constant is a number in Pa m^3
What are the results of work on a gas
increase in internal energy
increase in temperature
atmospheric pressure
Force exerted by the weight of the air above. If the density of the air is greater there will be more weight of air above a surface -> this means there will more particles in a given space so there are more collisions per second causing more pressure.
collsions between air molecules do not contribute to air pressure only collisions of molecules in air with a surface.
atmospheric pressure and altitude
Air pressure decreases with increasing altitude
what is the force acting on the object underwater
the weight of the water above it equals the force acting on it
what does the pressure in a liquid depend on?
depth and density of substanse and gravitational field strength
