Chem: Chapter 7
Energy
Capacity to do work or produce heat
Energy can be converted from one form to another but can be neither created nor destroyed
Law of conservation of energy
Energy due to position or composition Can also be a result of attractive and repulsive forces
Potential energy
Energy due to the motion of an object Depends on the mass and velocity of the object
Kinetic energy
involves the transfer of energy between two
objects
Heat
the force acting over a specific distance
work
Specific conditions that determine the transfer of energy between work and heat
pathway
a property of the system that depends only on its present state
State function
system
Part of the universe that is the current point of focus
exothermic
A reaction in which heat is expended termed Heat flows out of the system
endothermic
A reaction in which heat is absorbed is termed Heat flows into the system
Law of conservation of energy often called
first law of thermodynamics
Internal energy
the sum of the kinetic and potential energies of all “particles” in the system
At constant pressure
ΔH of the system is equal to the energy flow as heat
calorimeter
measures the heat associated with chemical reactions
Specific heat capacity
Energy required to raise the temperature of one gram of substance by one degree Celsius
Hess’s Law
In going from a particular set of reactants to a particular set of
products, the change in enthalpy is the same whether the
reaction takes place in one step or in a series of steps
Greenhouse effect
characterized by increase in temperature as observed in a greenhouse
expended based on the difference in potential energies between products and reactants
heat
gained by the surroundings must be equal to the energy lost by the system
energy
some of the potential energy is being converted to thermal energy through heat
in exothermic reactions
Standard Enthalpy of Formation
Change in enthalpy accompanying the formation of one
mole of a compound from its elements with all substances
in their standard states