Chapter 6 Thermochemistry Flashcards
Thermochemistry
Thermochemistry is the study of the relationships between chemistry and energy
Energy
The capacity to do work
Kinetic Energy
Energy due to motion
Thermal Energy
Energy associated with temperature. A type of kinetic energy
Potential Energy
Energy due to position or composition
Chemical Energy
Energy stored in the bonds of chemical compounds. A type of potential energy
Internal Energy
The sum of the kinetic and potential energies of all particles that compose a system
State Function
A function whose value depends only on the state of the system, and not how the
system arrived there
System
The thing that is under investigation
Surroundings
Everything with which the system can exchange energy
The Law of Conservation of Energy
Energy is neither created nor destroyed. AKA: the first law of
thermodynamics
Heat
The flow of energy caused by a temperature difference.
Temperature
A measure of thermal energy
Work
A force acting over a distance.
Enthalpy
The total heat content of a system
Heat of reaction
The amount of heat produced or absorbed by a chemical reaction. AKA: enthalpy of
reaction
Endothermic Reaction
Reaction that absorbs heat from its surroundings. Endothermic reactions have
a positive ΔHrxn
Exothermic Reaction
Reaction that gives off heat to its surroundings. Exothermic reactions have a
negative ΔHrxn
Bomb Calorimetry
Technique used to measure the ΔErxn. Carried out at a constant volume
Coffee Cup Calorimetry
Technique used to measure the ΔHrxn. Carried out at a constant pressure.
Hess’s Law
The enthalpy change of a chemical reaction is the same regardless of whether the reaction
occurs in one step or several steps. Can be used to calculate ΔHrxn
Standard State
Reference conditions for solids, liquids, and gasses
Standard Enthalpy of Formation
Change in enthalpy when 1 mol of a compound in its standard state
forms from its constituent elements in their standard states. Abbreviated ΔH°f
Standard Enthalpy Change for a Reaction
Change in enthalpy for a reaction when all reactants and
products are in their standard states. Abbreviated ΔH°rxn
