heat+temperature

• what is the equation relating energy, mass, specicific heat capacity and temperature?

  change in internal energy = mass X specific heat capacity X temperature change
• what is heat capacity?

  a measure of the energy needed to change the temperature of an object by 1 degrees C.
• what is specific heat capacity?

  the energy needed to change the temperature of a kilogram of a material by 1 degrees C.
• what happens to the particles when the temperature of a liquid decreases to melting point?

  the strength of the forces between particles increases and the liquid solidifies to become a solid.
• what happens to the particles if you heat a solid?

  the particles vibrate more energetically until they have enough energy to overcome the forces between them.
• what happens to the particles when the temperature of a gas decreases to the boiling point?

  the strength of the forces between particles increases and the particles condense to become liquid.
• what happens to particles if you heat a liquid?

  the particles move more energetically until they have enough energy to escape completely from the forces between them.
• what is specific latent heat?

  the latent heat per 1kg of mass
• when a susbstance changes state, why is the energy absorbed?

  used to create or weaken bonds
• when a solid becomes a liquid or a liquid becomes a solid, what is this hidden energy called?

  the latent heat of fusion
• when a gas becomes a liquid, or a liquid becomes a gas, what is this hidden energy called?

  the latent heat of vaporisation
• why isnt latent heat measured?

  the energy is transferred without the temperature changing.
• as we increase the temperature of an object, why do the particles move around more?

  gives kinetic energy to the particles.
• the hotter an object gets, the more its particles move around.
• the colder an object gets, the less its particles move around.
• what is absolute zero?

  the temperature where all the particles completely stop moving. They have zero kinetic energy.
• what temperature is absolute zero?

  0 K or -273 degrees C
• what is the equation for thermal capacity?

  thermal capacity = mass x specific heat capacity
• A glass jar has a metal lid that’s difficult to unscrew. Why does holding the jar under a hot tap help to open the lid?

  the metal expands at a greater rate than the glass for the same temperature increase and this loosens the lid.
• what are the steps in the thermal (heat) capacity experiment?

  1. the heater increases the internal energy of the body and we measure this using a joulemeter.
  2. measure the temperature of the body (object) at the start and measure the maximum temperature of the body at the end.
  3. specific heat capacity = change in internal energy / mass x maximum temperature rise
• what is conserved when substances change state?

  mass
• what can boiling also be called?

  vaporisation.
• what happens when the temperature of a gas decreases to the boiling point?

  the strength of the forces between particles increases and the particles condense to become a liquid.
• a substance's boiling point is the same as its what?

  condensing point.
• what happens if you heat a solid?

  the particles vibrate more energetically until they have enough energy to overcome the forces between them. This is when the solid melts (becomes liquid). The temperature needed for this to happen in the melting point.
• what is melting also known as?

  fusion
• what happens when the temperature of a liquid decreases to the melting point?

  the strength of the forces between particles increase and the liquid solidifies to become solid. For the same material, it's melting point is the same as its freezing point.
• what is latent heat?

  the energy that is transferred to a substance without the substance's temperature changing.
• what is specific latent heat?

  the latent heat per 1kg of mass.
• when a substance changes state, this energy is usually absorbed to create or weaken bonds rather than doing what?

  rather than transferring kinetic energy to a substance's particles.
• how do you convert celcius to kelvin?

  add 273
• how can you convert kelvin to celsius?

  subtract 273
• how can you detect latent heat?

  use a joulemeter and measuring the energy supplied to change state.
• What happens to the energy supplied during a change of state at both the melting and boiling points?

  kinetic energy remains constant while the potential energy increases.
• What term is used to describe the hidden energy when a solid becomes a liquid or a liquid becomes a solid?

  latent heat of fusion
• what are the steps of the specific latent heat of fusion experiment?

  1. gently heat ice in a funnel until it melts. Then measure the mass of the melted ice (water in the beaker).
  2. measure the amount of energy supplied by the heater using a joulemeter (this gives the energy change).
  3. calculate the specific latent heat of fusion by doing energy change/mass.
• what are the steps of the specific latent heat of vaporisation experiment?

  1. measure the mass of water in the beaker
  2. boil some water and then measure the mass of the water again.
  3. calculate the change in mass.
  4. measure the amount of energy supplied by the heater using a joulemeter wich gives us the energy change
  5. calculate the specific latent heat of vaporisation by doing energy change / change in mass.
• terms beginning with "specific" are measured per kilogram
• What two stores of energy are added together to calculate the internal store?

  kinetic and chemical stores
• What do we call the energy that is transferred to a substance without the substance's temperature changing?

  latent heat