free energy

temperature

entropy

heat

from the cold ice cube to your warm hand

the cold ice cube makes your hand cold

from your warm hand to the cold ice cube

no heat transfer occurs

thermochemical equation

enthalpy of combustion

formation reaction

molar enthalpy of vaporization

Both the marble molecules and the water molecules will slow down until they eventually come to rest.

The marble molecules will slow down while the water molecules speed up until they reach reach the same average kinetic energy.

The marble molecules will speed up while the water molecules will slow down until they reach nearly identical speeds.

Both the marble molecules and the water molecules will speed up until they reach nearly identical speeds.

endothermic

exothermic

reactant

product

In order for the reaction to happen, heat must be added to the system.

The process is exothermic

In order for the reaction to happen, heat must be added to the system.

The process is endothermic.

When the reaction happens, heat is released to the surroundings. The process is exothermic

When the reaction happens, heat is released to the surroundings. The process is endothermic

complete

at equilibrium

exothermic

endothermic

endothermic

exothermic