changes of state

    Cards (16)

    • conservation of mass
      mass is conserved during a change of state of a substance.
    • change of state
      A) liquid
      B) sublimation
      C) condensing
      D) melting
    • physical changes can be reversed [such as changing state] but chemical changes cannot be reversed.
    • specific heat capacity is the amount on energy required to raise 1 kg of a substance by 1℃
      energy = mass x specific heat capacity x change in temperature
    • specific heat capacity equation
      E = mcT
      energy = mass x specific heat capacity x CHANGE in temperature
    • specific latent heat is the energy required to change the state of 1 kg of a substance.
    • specific latent heat equation
      E = mL
      energy = mass x specific latent heat
    • specific latent heat of fusion is the changing of state between solids and liquids, --> freezing and melting
    • specific latent heat of vaporisation is the changing of state between liquid and gas, --> boiling and condensing.
    • latent heat is used when there's no change in temperature during phase transitions (melting/freezing or evaporation/condensation).
    • PAG - specific heat capacity
    • PAG - specific heat capacity
      1. use a mass balance to weigh the mass of the substance
      2. make sure the joulmeter reads 0
      3. measure the initial temperature of the substance and turn the power on.
      4. when the temperature has increased by a fixed amount [e.g. 10 degrees] record the energy on the joulemeter and the temperature increase.
      5. calculate the specific heat capacity
      6. repeat and calculate a mean
      7. use an insulating container and watch for systematic errors due to energy dissipating to the surroundings.
    • ways a substance can change state
      1. sublimation
      2. freezing
      3. melting
      4. evaporating
      5. condensing
    • sublimation: when a substance transitions from a solid to a gas without transitioning to a liquid in between
    • internal energy [of a substance]: energy stored by the particles, sum of kinetic energy and potential energies
    • specific heat capacity experiment
      1. use a mass balance to measure the mass of the substance.
      2. connect the joulemeter to an insulating container with a liquid or metal cylinder, and a thermometer.
      3. measure the temperature of the substance you're investigating, then turn on the power.
      4. when the temperature has increased by a fixed number of degrees, stop the experiment and record the energy on the joulemeter and the increase in temperature.
      5. calculate the specific heat capacity
      6. repeat 3 times and calculate the mean
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