Chapter 6: Thermochemistry Flashcards
Calorimetry
The measurement of heat changes
Chemical Energy
energy stored within the structural units of chemical substances
Closed System
A system that enables the exchange of energy but not mass with its surroundings
Endothermic Process
Processes that absorb heat from the surroundings
Energy
the capacity to do work or produce change
Enthalpy (H)
a thermodynamic quantity used to describe heat changes taking place at constant pressure
Enthalpy of reaction
the difference between the enthalpies of the products and the enthalpies of the reactants
enthalpy of solution
the heat generated or absorbed when a certain amount of solute is dissolved in a certain amount of solvent
exothermic process
processes that give off heat to surroundings
First Law of Thermodynamics
energy can be converted from one form to another, but cannot be created nor destroyed
Heat
transfer of energy between two bodies that are at different temperatures
Heat Capacity
the amount of heat required to raise the temperature of a given quantity of the substance by one degree C
Heat of dilution
the heat change associated with the dilution process
Heat of hydration
the heat change associated with the hydration process
Heat of solution
same as enthalpy of solution
Hess’s Law
When reactants are converted to products, the change in enthalpy is the same whether the reaction takes place in one step or in a series of steps
Isolated System
A system that does not allow the transfer of either mass or energy to or from its surroundings
Lattice Energy (U)
The energy required to completely separate one mole of a solid ionic compound into gaseous ions
Law of Conservation of energy
the total quantity of energy in the universe is constant
Open system
a system that can exchange mass and energy with its surroundings
Potential energy
energy available by virtue of an object’s position
Radiant energy
energy transmitted in the form of waves
Specific Heat (s)
The amount of heat energy required to raise the temp of one gram of a substance by one degree C
Standard enthalpy of formation
The heat change that results when one mole of a compound is formed from its elements in their standard states
Standard enthalpy of reaction
The enthalpy change when the reaction is carried out under standard-state conditions
Standard State
The condition of 1 atm of pressure
State function
a property that is determined by the state of the system
State of a system
The values of all pertinent macroscopic variables of a system
Surroundings
The rest of a universe outside of a system
System
Any specific part of the universe that is of interest to us
Thermal Energy
Energy associated with the random motion of atoms and molecules
Thermochemical equation
an equation that shows both the mass an enthalpy relations
thermochemistry
the study of heat changes in chemical reactions
thermodynamics
the scientific study of the interconversion of heat and other forms of energy
work
directed energy change resulting from a process
