Key Terms
Energy
The capacity to supply heat or do work. Work (w): causing matter to move against an opposing force.
Thermal energy
Kinetic energy from the random motion of atoms and molecules. Temperature: a measure of the average kinetic energy of pa
Exothermic process
Releases heat to surroundings. (q is negative)
Endothermic process
Absorbs heat from surroundings. (q is positive)
Heat capacity (C)
Heat required to raise the temperature of a specific object by 1°C. Extensive property — depends on both the type AND am
Specific heat capacity (c)
Heat required to raise the temperature of 1 gram of a substance by 1°C. Intensive property — depends only on type of sub
Calorimetry
The process of measuring heat transferred during a chemical or physical change.
Calorimeter
The device used to do it. The goal is to minimize heat exchange with the outside environment so all heat transfer is bet
System
The substance undergoing change. Surroundings: everything else, including the calorimeter contents.
Because energy is conserved
Heat lost by reaction = heat gained by solution, or vice versa.
Remember
Q-reaction = -q-solution, so if the solution temperature rises, the reaction released heat (negative q-reaction).
Calibration
Bomb calorimeters must be calibrated using a reaction with a known q before collecting data.
Internal energy (U)
The total energy stored in a substance (all kinetic and potential energy of its atoms and molecules).
Expansion work (pressure-volume work)
Work done when a system expands or contracts against external pressure.
Enthalpy
H = U + PV