Question | Answer |
energy | the ability to do work or transfer heat: energy= work + heat |
work | energy used to cause an object that has mass to move |
heat | evergy used to cause temperature of an object to rise |
potential energy | energy an pbject posseses by virtue of its position of chemical composition |
kinetic energy | energy an object posesses by its motion: KE= 1/2 mv^2 |
chemical energy | the energy stored within bonds of chemical substances |
radiant energy | comes form the sun and is earth's primary energy source |
thermal energy | energy associated with the random motion of atoms and molecules: proportional to Kelvin |
nuclear energy | energy stored within the collection neutrons and protons in the atom |
thermodynamics | study of heat and its transformations |
thermochemistry | branch of thermodynamics that deals with thte heat involved with physical and chemical changes |
fundamental premise | when energy is transferred from one object to another it apears as work and or as heat |
system | composed of particles with their own internal energies (E or U) |
internal energy | of a system, that is the sum of all kinetic and potential energies of all components of a system (E) |
heat 2 | energy can also be transferred as heat: flows from warmer objects to cooler objects |
thermochemistry | a study of heat change in chemical reactions: this can be endo- or exo- |
heat 3 | the transfer of thermal energy between two bodies that are at differenct temperatures |
temperature | the measure of the thermal energy |
First Law of thermodynamics | energy is niether created nor destroyed: energy of the universe is constant: if system loses energy must be gained by surroundings and vice versa |
pressure | force per unit area |
state function | internal energy of a system is independent of the path by which the system achieved that state |
enthalpy | heat of a reaction, the internal energy plus the product of pressure and volume |
enthalpies of chemical change | heats of a reaction; amount of heat exchanged per mole of a substance produced |
exothermic | heat flows out of the sytem into the surroundings and change of H is a negative sign |
endothermic | heat flows into the system from surroundings and change of H is a positive sign |
calorimetry | science of measuring heat changes (q) for chemical reactions |
bomb calorimetry | measures the heat change at constant volume such that q= change in E |
constant pressure calorimetry | measures the heat change at constant pressure such that q= change in H |
heat capacity | amount of heat required to raise the temperature of an object or substance one degree C or K |
specific heat | amount of heat required to raise one gram of substance by one degree C |
molar heat | amount of heat required to raise the temperature of 1 mole of substance 1 degree |
Hess's law | overall enthalpy change for one reaction is equal to the sum of the enthalpy changes for the individual steps in the reaction |
standard heat of formation | enthalpy change for the formation of one mole of substance in standard state from its constituent element |
thermodynamic standad states | most stable form of a substance at one atm and 25 degrees C and one molar concentration for all |