Thermochemistry

ability to work or produce heat

based on the composition or position of an object

energy of motion

states that in any chemical reaction or physical process, energy can be converted from one form to another, BUT neither CREATED NOR DESTROYED

energy stored within bonds

• sugar and fats have this

breaking down of sugars and fats, much of the energy is released as heat

energy in the process of flowing from a WARMER —> COOLER object

• q

• (delta)H : heat of reaction

SI unit of heat and energy

1000 j =

1000 calories =

1 cal =

4.184 j/g°C

amount of heat required to raise the temperature of 1 gram of a substance by 1 °C

• c

formula to calculate heat released or absorbed

(delta)T

insulated device used for measuring amount of heat absorbed/released during a chemical of physical process

• can determine the specific heat of an unknown metal

study of heat energy accompanying chemical reactions and phase changes

balanced equation including energy change

• expressed as change of enthalpy

heat required to vaporize (boil or condense) 1 mol of a liquid

heat require to melt or freeze 1 mol of a solid

graph showing phase changes as temperature increases/decreases

speed of a chemical change over an interval of time

atoms, ions, and molecules must collide in order to react

• however, NOT ALL COLLISIONS FORM REACTIONS

short lived period when once molecules collide, the energy is the highest

• highly unstable

minimum energy required to form activated complex.

• directly influences rate or reaction

reactivity directly influences rate of reaction

# of particles in a given volume directly influences rate

directly affects rate because of increased/decreased collision frequency

• particle SIZE and SA are opposite

directly affects rate by increasing kinetic energy, both collision FREQUENCY and ENERGY are affected

• ONLY factor changing energy

substance that increases reaction rate without being used up

• lowers activation energy = more successful collisions

when temperature is stagnant during a phase change, the energy is being used to break __

Complete burning of 1 mol of a substance

products have LESS energy than reactants

Energy released

grinding a substance into a powder ____, which will increase the rate of reaction.