energetics terms

Thermochemistry

the study of energy changes associated with chemical reactions

Temperature

the measure of the average kinetic energy of the particles

Heat

the transfer of thermal energy between two bodies at different temperatures

system

the area of interest

surroundings

the rest of the universe outside of the system

universe

the combination of the item under investigation and the immediate factors that can influence it

open system

can exchange both mass and energy with surroundings, usually in the form of heat

closed system

can exchange energy (not mass) with surroundings

isolated system

does not allow mass or energy transfer with surroundings

enthalpy

the total energy of a system, some of which is stored as chemical potential energy in chemical bonds

bonds broken

requires energy, endothermic

bonds formed

releases energy, exothermic

standard enthalpy of reaction

change in enthalpy at 25*C and 1atm (SATP)

specific heat capacity

the amount of energy required to raise the temperature of one gram of a substance by one degree celsius/kelvin

standard enthalpy change of formation

the enthalpy change when one mole of compound is formed from its elements in their standard states at 298K and 1 atm (SATP)

[P-R]

enthalpy of combustion

the energy released when one mole of a compound is burned in excess oxygen

[R-P]

Hess’s Law

the total change in enthalpy for converting reactants to products is constant, regardless of the way in which the change occurs

Bond Enthalpy

The amount of energy required to break a particular bond in one mole of gaseous molecules

Lattice Enthalpy

the energy required to completely separate one mole of solid ionic compound into gaseous ions

Atomization

the energy required to change on mole of gaseous molecules into one mole of gaseous atoms (if diatomic), or the energy required to change one mole of solid atoms into one mole of gaseous atoms (if not diatomic)

First Ionization Energy

The energy needed to remove one or more electrons from a neutral atom to form a positively charged ion

Electron Affinity

the energy given off when a neutral atom in the gas phase gains an extra electron to form a negatively charged ion.

Entropy

the measure of randomness in a system

standard entropy change

entropy change at standard conditions

spontaneous process

a reaction that occurs under a given set of conditions without external assistance

combustion reaction

a chemical change in which an element or a compound reacts with oxygen, often producing energy in the form of heat and light

coal

complex and solid material derived primarily from plants that died and were buried hundreds of millions of years ago and were subjected to high temperatures and pressures

crude oil

a mixture of straight, branched and cyclic alkanes

biological carbon fixation

the production of organic compounds from carbon dioxide

biofuels

renewable resources, produced from organic compounds

fuel cell

converts chemical energy of a fuel directly into electrical energy