SP14a - SP14e test 1 Flashcards
What is Sublimation?
When a solid turns into a gas without turning into a liquid first
What is the Kinetic theory?
it states that everything is made of tiny particles
Why cant solids be compressed?
because strong forces of attraction hold the particles closely together
What are the properties of liquids?
forces of attraction aren’t strong enough to keep the fast moving particles in place so they are not in fixed positions
therefore they can move past each other which means they take the shape of their container
The particles are still very close together which means they can also cant be compressed
What does it mean when a mass is conserved during a change of state?
When a change of state occurs mass is conserved which means mass is neither gained nor lost (stays the same)
can gasses be compressed ? why?
Yes, because the particles are far apart due to the weak forces of attraction between them
What is a Physical change?
a change is considered a physical change when no new substances are formed and the substance recovers its origin properties if the change is reversed
How do you calculate density?
Density = mass / volume
Do Chemical changes conserve mass?
yes
How are chemical changes different to physical changes?
chemical changes in a substances often cannot be reversed whilst in physical changes then can[
Why do solids usually have higher density’s than their liquid form?
the particles in solids are closer together meaning they will have the same weight in a smaller volume resulting in a higher density
What is thermal energy?
energy that is stored by heating, for example in the movement of particles
What are the units for density?
kg/m3 and g/cm3
Kilogram per cubic meter
Gram per cubic centimeter
what is the apparatus for the volume experiment?
Displacement can
Measuring Cylinder
Using the volume experiment explain how you would measure the volume of a bolt?
First fill the displacement can to the brim.
Then place a measuring cylinder next to it.
Measure initial volume in cylinder (if any).
slowly place bolt into displacement can.
measure new volume of measuring cylinder
Subtract initial to find volume of bolt.
How does temperature change affect different substances?
when a solid stores more thermal energy the vibration of its particles increase
When liquids and gases store more thermal energy their speed increases
How do you maintain a store of thermal energy?
by reducing heat loss that is transferred to the surroundings. To do this you need to insulate the object by surrounding it with wool, foam or bubble warp
What is meant by the ‘Specific Heat Capacity’ of a material?
the amount of energy it takes to increase the temperature of 1kg of that material by 1 Degrees Celsius
What is meant by the ‘Specific latent heat’ of a material?
The amount of energy it takes to make 1kg of this substance change state
What factors affect the amount of heat needed to change the temperature of a substance?
type of material
mass
amount of temperature rise
What is the formula of change in thermal energy?
Change in thermal energy = mass * specific heat capacity * change in temperature
In what units is thermal energy measured in?
Joules
In what units is specific heat capacity measured in?
Joules / kilograms ( J/Kg)
In what units is specific latent heat measured in?
Joules / kilograms ( J/Kg)
What is the formula of thermal energy needed for a change of state?
thermal energy needed for a change of state = mass * Specific latent heat
How does kinetic energy correlate to temperature in gas particles?
the higher the temperature the higher the average kinetic energy in the gas particles
What is the unit for pressure?
Pascals (Pa)
What is the coldest temperature possible called?
Absolute Zero
What is the lowest achievable temperature?
-273 Degrees celsius
What happens to the gas particles of a gas that reaches absolute zero?
its particles completely stop moving
How does the kelvin temperature scale measure temperature?
it measures temperature relative to absolute zero
How much is 0 Kelvin in degrees Celsius?
-273 (Absolute Zero)
How do you convert Kelvin to degrees Celsius and reverse?
To convert from Kelvin to degrees Celsius, subtract 273
To convert from degrees Celsius to Kelvin , add 273
What are some things we can do to keep the volume experiment fair?
repeat and find average
take measurements at eye level
What is parallax error? how do you avoid it?
it is when you view the water level at an angle to it seems to be at a different level than it actual is
take measurements at eye level
What is the apparatus for the Specific heat capacity experiment?
Polystyrene cup / insulated cup
Beaker
Battery-Powered balance
Thermometer
Support stand
electric heater
stirrer
joulemeter
Describe the Melting ice experiment.
Place a boiling tube full of crushed ice into a pyrex beaker
put a thermometer and record the temperature
place the beaker onto a tripod and gauze
pour hot water from a kettle into the beaker and keep it warm using a Bunsen burner
measure temperature of ice in 1 minute intervals and record them
stop recording 3 minutes after the ice has melted
note the times at which the ice starts to melt and when it appears to be completely melted
Describe he Specific heat capacity experiment.
Place a polystyrene cup in a beaker
place the lid
then place all of this onto a electric scale and zero the balance
fill the cup almost to the top with water and write down its balance
carefully remove the cup from the balance
place a thermometer into the water and support it
place the eclectic immersion heater into the water
make sure heater is completely below water level
connect the heater to a joulemeter
record initial temperature of water
switch heater on
using the thermometer stir the water gently
after 5 minutes record the temperature of the water
write down the reading on the joulemeter
