End Of Unit Questions Flashcards
Why does a solid have a fixed volume?
All particles are held together in fixed positions
When a liquid evaporates, why is the average kinetic energy of the remaining molecules reduced?
Most energetic molecules leave the liquid, so the average kinetic energy of the remaining molecules is reduced
What happens to the rate of energy transfer between an object and its surroundings if the temperature difference between them is reduced?
If the temperature difference is reduced, the rate of energy transfer decreases
Which types of energy transfer involve particles?
Conduction, convection, evaporation and condensation
How does energy from the sun reach the earth?
Infrared radiation
How does the colour of a surface affect the rate of conduction?
No effect
Why are gases poor conductors?
They are far apart
Why are metals the best conductors?
They have delocalised electrons that transfer energy by collision very quickly
What is convection?
Convection is the movement of energy through a fluid by movement of the fluid itself
How does cavity wall insulation reduce energy transfer from a house?
It traps the air in the cavity in pockets so prevents convection currents
The specific heat capacity of water is 4200J/kgc. How much energy is needed to raise the temperature of 3kg of water by 4c?
50,400J
What is the best colour for a central heating radiator, glossy white or dull black and why?
Dull black, because it emits the most radiation
