Unit 14 & 15 - Particles Model/ Forces And Matter Flashcards
What is sublimation?
When a solids turns straight into a gas without becoming a liquid
What is the kinetic theory?
The theory that states that everything is made out of tiny particles
Name 2 characteristics of a solid
The particles vibrate and cannot cube compressed
Name 2 character is of liquids
Cannot be compressed, particles roll over eachother
Name of 2 characteristics of gases
They move quickly, can be compressed
What is the equation for density
Density = mass/ volume
Explain the core practice - investigating densities (for liquids)
Out an empty beaker on a balance and set to 0
Measure 50cm of liquid and pour into a beaker
Measure mass of this
Explain the core practical - investigating densities (for solids)
Find mass of a solid
Find volume of solid - using a displacement can (beaker with spout), add water and place object inside. Make sure that the whole object is inside the water but not your finger
How can you maintain a store of thermal energy?
The amount of energy that is transferred to the surroundings needs to be reduced e,g insulation
What does the amount of thermal energy stored depend on?(3)
Temperature
Mass
Material
What is the specific heat capacity?
The amount of energy it takes to increase the temp of 1kg by 1C
Why does the temperature stay constant during state change?
The extra energy is used to break the bonds
What is the specific latent heat
The amount of energy it takes for 1kg of substance to change state
Why is specific latent heat sometimes specific latent heats? (Plural)
It takes less energy to melt that evaporate
What is the equation for change in thermal energy?
Change in thermal energy = mass x specific heat capacity x change in temp
What is the equation for thermal energy needed for state change?
Energy for state change = mass x specific latent heat
Explain the core practical - investigating water (melting ice)
Put a boiling tube with crushed ice into a pyrex beaker
Measure temp using thermometer
Add hot water into beaker and place over Bunsen to keep warm
Measure temp of ice every minute until melted
Explain the core practical - investigating water (specific heat capacity)
Put a polystyrene cup in a beaker, set balance to zero with it on
Fill with water near to top and measure mass
Remove from balance and put a thermometer inside it
Put a 12V electric immersion heater into the water and connect it to a joulemeter
Record temp of water then turn on the heater and record temp after 5 mins
What is pressure caused by
Forces acting on the walls of a container as a result of moving particles hitting the wall
How does an increased temperature cause the pressure to increase
The particles move faster
What are the units for pressure
Pascals = Pa
Why can measurements for pressure not be made below the boiling point
It has become a liquid
What is absolute zero
When the graph line meets zero on the x axis (-273C) because it is the coldest possible temp
Powhatan is the kelvin temperature scale?
It measures temperatures relative to absolute zero (K)
What is 273 kelvin equivalent to
0C
What is gas pressure
The effect of gas particles hitting a surface which causes a force
How does gas pressure act on walls
At right angles
When does the force on the walls of the container of a gas increase
If the same number of particles is forced into a smaller volume
What is the equation showing how volume and pressure of a fixed mass of a gas is constant at a constant temperature
P1 x V1 = P2 x V2
What happens when you push a bike pump to make it warm
The force is transferring energy to the gas inside the pump (work done)
How many forces cause stretching, bending or compressing?
More than one
What does elastic mean
When something will return to its original shape when forces are removed
What does inelastic mean
When something keeps its new shape after the forces have been removed
Why are metals sometimes elastic and inelastic
They can be made into spring that are elastic but if the force is too big, they are permanently deformed
What is the extension of a spring
The change in length when forces are applied
What type of correlation is there between the forces applied and the extension
Directly proportional
What is the spring constant
The force needed to produce an extension of 1 metre
If a spring is stiff, how big is the spring constant
Large
What is the equation for spring constant
Spring constant = force/ extension
What are the units for spring constant
N/m
What is the equation for energy transferred in stretching
Energy transferred = 1/2 x spring constant x extension^2
Explain the core practical - Investigating springs
Set up clamp with spring and a ruler below inline with the bottom
Measure length of spring with no weights
Hand a 1N mass on the spring and measure extension
Repeat with 10 different masses
Repeat for a different spring
Calculate spring constant for each spring
What is pressure measured in
Pascals
What is pressure
A measure of the force on a unit where the force is normal to the surface
What is the equation for pressure
Force/ surface area
What is atmospheric pressure
Pressure from the air
What does the pressure of a fluid depend on (2)
The depth of the fluid and density
Why does the pressure increase in deeper liquids
There is more weight of fluid above
How many more times is water dense than air
Over 800 times
What is the pressure at sea level
About 100,000 Pa
What is the equation for pressure due to a column of liquid
Pressure = height of column x density of liquid x gravitational field strength
What is upthrust
A force on an object die to the difference in pressure
What is the upthrust equal to
The weight of the water displaced by the object
