Specific Heat Capacity

• What is Specific Heat Capacity?

  The amount of energy taken to raise 1kg of a material by 1 degree celcius
• How can Specific Heat Capacity be worked out?

  SHC = energy / (mass x temp change)
• Do different substances have different Specific Heat Capacities?

  Yes, e.g. 4200J to warm 1kg of Water by 1C but only 139J to warm 1kg of Mercury
• What is noticeable about a substance that requires a lot of energy to heat up?

  It can also release large amounts of energy when they cool down again
• What is the Formula for Specific Heat Capacity?

  Energy transferred (J) = mass (kg) x specific heat capacity (J/kgC) x temperature change (C)

  
• How much energy is needed to heat 2kg of Water from 10C to 100C.c = 4200J

  2kg x 4200J x 90C = 756000J
• An empty 200g aluminium kettle cools down from 115C to 10C, losing 19068J of heat energy. What is the specific heat capacity of Aluminium?

  E = m x c x TE / m x T = c19068 / 0.2 x 105 = 908 J/kgC
• Why are heaters made of materials that have high heat capacities?

  So they can store lots of heat energy.
• What are the advantages of a water heater system (radiator)?

  Water has a very high Specific Heat Capacity and a liquid can be pumped around in pipes to circulate heat easily.
• What are the advantages of an electric storage heater system?

  Can store energy at night (when electric is cheapest) and release during the day.
• What are the advantages of oil filled heaters?

  Oil has a higher boiling point so can safely reach higher temperatures when heating compared to water.
• What is the unit of energy?

  J
• What is the unit of mass?


  kg
• In the SHC experiment, why is your value not the same as the experimental value?

  Not all heat from the immersion heater is transferred to the substance being heated - some is transferred to the surroundings
• How can you improve the reliability of data?

  Repeat the experiment and average after discarding any anomalous results
• How can you improve the precision of data?

  Use more sensitive equipment, e.g. a digital thermometer to work out the temperature change.
• How can you improve the accuracy of data?

  Improve method, e.g. surround immersion heater in the metal block with oil so heat is distributed more evenly (air gap is an insulator)