P2- Energy Transfer By Heating Flashcards
What is the specific heat capacity of a a substance?
The amount of thermal energy required to raise the temperature of 1kg of that substance by 1°C.
What is the specific heat capacity equation?
Change in thermal energy = mass x specific heat capacity x change in temperature
E = m x c x ΔT
What is energy measured in?
Joules (J)
What is SHC measured in?
J/kg°C
What is temperature measured in?
°C
What’s the specific heat capacity equation for practical?
Heat supplied to material
Specific heat capacity
————————————————
Mass x change in temperature
What apparatus do you need for the specific heat capacity experiment ?
- 1kg block of substance (if water then a beaker)
- thermometer
- appropriate heater (e.g: immersion heater)
- power source
- joule meter or volt meter, a meter or stopclock
Explain the SHC experiment:
- start by assembling the apparatus and measuring the initial temperature of the substance.
- turn on power supply and start stop-clock.
- whilst the power supply is on take several periodic measurements of the voltage and current and calculate average of these values.
- after 5 mins (300 seconds) switch off power supply, stop the stop-clock and leave the apparatus for a few more minutes.
- monitor the thermometer and make note of highest temp reached.
- calculate rise in temp.
What is the equation for working out heat supplied to a substance?
Energy = current x voltage x time
Time must be in seconds
Specific heat capacity experiment part 2:
- these values along with mass of substance can be substituted into the equations find the SHC of substance.
- biggest problem with experiment above is that not al of the heat supplied by the heater will go in to substance some will go into surrounding and substance will also lose heat whilst being heated.
- this means that the value for heat added will be too great which means that the calculated SHC will also be too great
