internal energy Flashcards
describe the particles in a solid
particles are very close together and vibrate in a fixed position randomly
describe the particles in a liquid
particles are close and always touching and move randomly past each other
describe the particles in a gas
Particles are further apart on average.
Particles move at higher speeds randomly colliding with each other.
When a system changes from a solid, to a liquid, to a gas
The particles average kinetic energy and average potential energy increases
between particles there are…
Intermolecular forces
Where are intermolecular forces?
In-between 2 particles (atoms too)
what happens to intermolecular forces when a system changes
When a system changes from a solid to a liquid to a gas, some of the intermolecular forces are overcome
Define internal energy
The sum of the randomly distributed kinetic and potential energies of the particles in a system
A systems internal energy increases when…
The systems average kinetic energy and average potential energy increases
Explain why dry ice has the lowest potential energy (3 MARKS)
The potential energy of a substance is due to the relative positions of its particles with respect to one another.
The further apart the particles the greater the potential energy.
In solids particles are closest to each other so dry ice will have the lowest average potential energy
define thermal energy
The sum of the randomly distributed kinetic energies of the particles in a system
When energy is transferred to a system by heating…
its internal energy increases
when energy is transferred from a system by heating
its internal energy decreases
describe the change in internal energy that occurs when a hot rod is placed in a block of ice. (NOT DONE)
Energy is transferred by heating from the hot rod to the ice.
This energy transfer has increased the average kinetic energy of the particles.
