P1.2.3 - Specific heat capacity

• Q1. Why does pool water feel so cool when the air temperature is so high?

  You need to transfer a great deal of energy to water to raise its temperature. The concrete around a swimming pool is much hotter when in those conditions, than the water due to it taking a lot less energy to raise the temperature of the concrete by 1 degree rather than the pool by 1 degree
• Q2. What factors does the amount of energy needed to raise the temperature of an object depend on?

  • the type of material
  • the mass of the material
  • the temperature rise
• Q3. What is the definition of specific heat capacity?

  The energy needed to raise the temperature of 1kg of a material by 1 degree.
• Q4. What does heating increase?

  The internal energy. This happens by when you heat something up the particles gain energy in its kinetic energy store which increases their internal energy
• Q5. What is internal energy?

  The energy that relates to motion , vibration , rotation and arrangement of particles.
• Q6.

  Here shows the setup and equipment used to measure the heat capacity of water

  
• Q7. How do you calculate with Specific heat capacity?

  Change in thermal energy (J) = Mass (Kg) x Specific heat capacity (J/kg°C) x Change in temperature (C°)
• Q8. Calculate the energy you need to transfer to raise the temperature of a 500g block of aluminium by 10°C. The specific heat capacity of aluminium is 913J/kg°C ( HINT) Use the equation change in thermal energy = mass x specific heat capacity x change in temp

  Answer = 4600J

  Step 1 : Write down what you know and covert qualities to standard units

  mass = 500g = 0.5kg

  specific heat capacity = 913J/kg°C

  change in temp = 10°C

  Step 2 : put numbers into correct equation

  Change in thermal energy = mass x specific heat capacity x change in temp

  0.5kg x 913J/kg°Cx10°C = 4576 = 4600 ( 2 sig fig)
• Q9.

  Specific heat capacity tells you how resistant a material is to a change in temperature.
• Q10. Why is it good that water is resistant to temperature change?

  It makes it a good material to use in central heating systems. Also means that oceans are less likely to freeze
• Q11. Why are saucepans made of materials with low specific heat capacities?

  Because they need to heat up quickly
• Q12. What other consideration is there when choosing a metal to make a saucepan?

  Gold and platinum may have very low specific heat capacities but are very expensive and some metals are poisonous
• Q13.

  Temperature is a measure of the average internal energy of all the particles in the substance