Temperature (T)
average kinetic energy of all particles in an object
measured in Kelvin (K)
Heat (Q)
Thermal energy transferred from one object to another.
naturally flowing from hot objects to cold objects
measured in joules (J)
Enthalpy (H)
Internal energy of a particle
More commonly, we focus on energy change
measured in kJ/mol
Unless otherwise stated, all reactions occur at…
STP
100 kPa and 298 K
endothermic
energy transferred from surroundings to system
postive delta H
temperature of surroundings is reduced
products are higher in energy, less stable
exothermic
energy is transferred from reaction (system) to the surroundings.
negative delta H
increase in surrounding temperature
products lower in energy, more stable
What is the enthalpy of formation for any element in its standard state?
0
standard enthalpy change of formation
1 mole of a substance forms from its constituent elements
standard enthalpy change of combustion
1 mole of a substance completely burns in oxygen
standard enthalpy change of neutralization
1 mole of water is produced when an acid reacts with an alkali