Thermal energy Flashcards
when is electrical potential energy maximum?
when atoms are close together,potential energy is maximum and negative
potential energy when atoms are separated?
maximum and has a value of zero.
in gaseous state potential energy of particles?
maximum or zero.
what is temperature?
measure of average kinetic energy of the molecules.
why does melting take much less energy than boiling?
after melting molecules are still bonded to most of the neighbours.In boiling each molecule breaks free of all its neighbours. Hence, more bonds are broken in boiling.
evaporation?
when a liquid changes to gas without boiling .
evaporation process?
some molecules move faster than other and may breakk free from the liquid.They form the vapour above the liquid and energetic molecules evaporate away.
why is evaporation a cooling process?
energetic molecules escape.molecules with a below average kinetic energy remain. as temperature Is a measure of average kinetic energy, temperature of the liquid falls.
what is internal energy?
sum of random distribution of kinetic and potential energies of its atoms or molecules.
why does a gas gets hotter when it is compressed?
the molecules of the gas strike the moving wall(piston) and bounce off faster gaining kinetic energy.hence, the temperature rises.
first law of themodynamics?
increase in internal energy= energy supplied by heating + energy supplied by doing work.
thermal energy?
energy flowing from a region of higher temperature to a region of lower temperature.
thermal equilibrium?
when two objects are in contact with each other and are at the same temperature, there will be no net transfer of energy.
absolute zero?
temperature at which all substances have minimum internal energy.
celcius to kelvin?
celcius + 273.15K
