Specific Heat Capacity - State Of Matter Flashcards
Energy transferrance by heating
As a material is heated, energy is transferred to thermal energy store.
This causes temperature increase.
You need to be able to describe the changes in how energy is stored when an object is heated.
Eg, if you boil water in a kettle -
Energy is transferred electrically to the thermal energy store of the kettles heating element
Energy is transferred by heating to the kettles thermal energy store.
So temperature increases.
Why do different materials have different specific heat capacities?
Some materials need more energy to increase their temperatures than others.
These materials also transfer more energy when cooled again.
Can also ‘store’ a lot of energy,
The amount of energy stored or released as a material changes temperature depends on specific heat capacity of the material,
Energy can be found using - changes in thermal energy = mass x specific heat capacity x temperature change
How to investigate specific heat capacity of a solid block.
Measure the mass of the block.
Wrap it in insulating layer to reduce energy loss.
Get power supply, ammeter, connect all
Turn on power supply and start a stop watch
Record potential difference, v, of the power supply and current, l. They shouldnt change at all.
After ten mins, take a reading of the blocks temperature.
Turn off heater and work out temperature change.
Calculate power of heater using P =VI
How to calculate specific heat capacity in solid block practical
When calculating specific heat capacity, you need to know about work done and energy transferred
When you turn on power, the current in the circuit does work on the heater
Energy is transferred electrically from the power supply to the heaters thermal energy store.
Energy is transferred to the heater given E=Pt (power of heater x time heater is on for)
This energy is then transferred to materials thermal energy store by heating
So the value of E you calculate in step 3 is equal to the change in thermal energy of the block, and you can find it to find specific heat capacity of block.
