Heat Energy
Heat energy
Temperature – measure of the average KE of the particles in a substance, measured in degrees Celsius or degrees Kelvin. Celsius 0⁰C (freezing point of water) to 100⁰C (boiling point of water) Kelvin 0 K (absolute zero, particles stop moving theoretically), equivalent to -273.15⁰C. Uses the same scale for increase, ie. a 1⁰C increase in temperature equates to a 1K increase in temperature.
Heat – amount of energy transferred, measured in Joules (J) Kinetic Energy,
Thermal Equilibrium
When you put HOT and COLD substance together they will move toward thermal equilibrium
Q(out) Q(on)
Q – Heat Energy, measured in Joules (J)
Specific heat capacity
Specific heat larger, heat faster.
Question: Do all objects increase their temperature at the same rate when heated?
NO, due to variation in molecular structure and bonds of different materials. (ie. when cooking a metal spoon gets hotter faster than a wooden spoon)
E.G. Sand get hotter than the same amount of water at the beach, this is because SAND only requires 880J of heat energy from the SUN to raise its temperature by 1⁰C, whereas WATER requires 4200J of heat energy.
Q – Heat Energy in Joules (J) m – mass in kg c – Specific Heat Energy (J/kg/K) or (J/kg/⁰C)
ΔT – change in temperature in K or ⁰C
Rearrange
Specific Heat Capacity, c, is the amount of energy required to raise the temperature of 1 kg of a substance by 1K or 1⁰C.
Latent Heat
When a substance is heated to the extent it change state, it undergoes a phase change.
The additional heat causes the molecules to vibrate faster, causing the temperature to increase.
At heating continues the molecules will reach a point where they break free of their molecular bonds.
Once a liquid has reached its ‘boiling point’ the added heat energy does not raise the temperature of the liquid, the energy goes in to breaking the molecular bonds.
Temperature – measure of the average KE of the particles in a substance, measured in degrees Celsius or degrees Kelvin. Celsius 0⁰C (freezing point of water) to 100⁰C (boiling point of water) Kelvin 0 K (absolute zero, particles stop moving theoretically), equivalent to -273.15⁰C. Uses the same scale for increase, ie. a 1⁰C increase in temperature equates to a 1K increase in temperature.
Heat – amount of energy transferred, measured in Joules (J) Kinetic Energy,
Thermal Equilibrium
When you put HOT and COLD substance together they will move toward thermal equilibrium
Q(out) Q(on)
Q – Heat Energy, measured in Joules (J)
Specific heat capacity
Specific heat larger, heat faster.
Question: Do all objects increase their temperature at the same rate when heated?
NO, due to variation in molecular structure and bonds of different materials. (ie. when cooking a metal spoon gets hotter faster than a wooden spoon)
E.G. Sand get hotter than the same amount of water at the beach, this is because SAND only requires 880J of heat energy from the SUN to raise its temperature by 1⁰C, whereas WATER requires 4200J of heat energy.
Q – Heat Energy in Joules (J) m – mass in kg c – Specific Heat Energy (J/kg/K) or (J/kg/⁰C)
ΔT – change in temperature in K or ⁰C
Rearrange
Specific Heat Capacity, c, is the amount of energy required to raise the temperature of 1 kg of a substance by 1K or 1⁰C.
Latent Heat
When a substance is heated to the extent it change state, it undergoes a phase change.
The additional heat causes the molecules to vibrate faster, causing the temperature to increase.
At heating continues the molecules will reach a point where they break free of their molecular bonds.
Once a liquid has reached its ‘boiling point’ the added heat energy does not raise the temperature of the liquid, the energy goes in to breaking the molecular bonds.