GEN CHEM 3 Flashcards
(36 cards)
It refers to the capacity to do work.
Energy
It has neither mass nor volume.
Energy
Has no concrete form, but it can only be detected based on its effects.
Energy
is the study of the energy changes associated with chemical processes.
Thermochemistry
is the study of energy and its transformations.
Thermodynamics
allows us to “keep track” of energy change.
The first law of thermodynamics
is defined as the energy that is either released or absorbed due to differences in temperature conditions.
Heat
is defined as the result of a force acting through some distance
Work
is a region containing energy and/or matter that is separated from its surroundings by arbitrarily imposed walls or boundaries.
system
Everything external to the system is—
surroundings
When heat is lost by the system, it must be transferred to the surroundings. In such a case
qsys is negative, and qsurr is positive
When heat is absorbed by the system, it is taken from the surroundings, so
qsys is positive (qsurr is negative).
When qsys >0, the reaction is
endothermic
A reaction in which qsys < 0 is called an
exothermic reaction
The total energy of the universe is
finite
work is done by the system on the surroundings.
Expansion
Work done by the system is—because the system now has that much less energy.
ALWAYS NEGATIVE
work is done on the system by the surroundings.
Compression
Work done on the system is–. Energy from the surroundings is transferred into the system, so the system gains that energy.
ALWAYS POSITIVE
Some chemical reactions are accompanied by either the
absorption or liberation of heat.
The total heat absorbed or liberated in a chemical reaction is called
heat of reaction.
The heat content of the reacting system is known as the–. It is the total energy of a system at constant pressure.
enthalpy, H
Enthalpy can be experimentally determined by performing
calorimetry
a reaction is carried out inside an insulated vessel then the temperature is measured before and after the reaction.
calorimetry
