Changes of state

Cards (16)

  • When a substance changes state, mass is conserved.
  • A solid changing to a gas is called subliming.
  • When a gas turns into a liquid, it is called condensation.
  • Changes of state are physical changes that differ from chemical changes because the material recovers its original properties if the change is reversed.
  • Internal energy is energy stored inside a system by particles (atoms and molecules) that make up the system.
  • Internal energy is the total kinetic energy and potential energy of all the particles (atoms and molecules) that make up a system.
  • Heating changes the energy stored within the system by increasing the energy of the particles that make up the system. This either raises the temperature of the system or produces a change of state.
  • If the temperature of the system increases, the increase in temperature depends on the mass of the substance heated, the type of material and the energy input to the system.
  • to calculate the change in thermal energy, use E=∆ E =mcθ m c ∆ θ
  • The specific heat capacity of a substance is the amount of energy required to raise the temperature of one kilogram of the substance by one degree Celsius.
  • The specific latent heat of a substance is the amount of energy required to change the state of one kilogram of the substance with no change in temperature.
  • When a change of state occurs, the energy supplied changes the energy stored (internal energy) but not the temperature.
  • to calculate the energy needed for a change of state, use E=E =mL m L
  • The molecules of a gas are in constant random motion
  • The temperature of the gas is related to the average kinetic energy of the molecules.
  • Changing the temperature of a gas, held at constant volume, changes the pressure exerted by the gas.