Specific Latent Heat Flashcards
Why is energy released when a substance condenses or freezes?
Bonds are forming between the particles of the substance, which releases energy
What is the difference between specific latent heat and specific heat capacity?
Specific latent heat is the energy required to change the state of 1 kg of a substance without changing the temperature, and the specific heat capacity is the energy required to raise the temperature of 1 kg of a substance by 1°C.
How would you create a temperature-time graph for ice melting into water then boiling?
E.g. fill a beaker with crushed ice and record the temperature of the ice using a thermometer. Use a Bunsen burner to gradually heat the beaker full of ice, recording the temperature of the ice every 20 seconds. Continue this process until the ice has melted the water begins to boil, then use the results obtained to plot a graph of temperature against time.
Explain why the temperature does not rise when a substance that is being heated changes state.
The energy transferred to the substance is being used to break the bonds between particles rather than to raise the temperature
The energy needed to change 4 kg of a substance from a solid to a liquid is 240000 J. Use the formula below to calculate the specific latent heat of the substance for this change of state.
thermal energy = mass x specific latent heat
60000 J/kg
specific latent heat = thermal energy / mass = 240000 / 4 = 60000J/kg
