Chapter 7 Flashcards
is the study of the
relationship between energy and matter.
Thermochemistry
is anything that has the capacity to
do work.
energy
is a force acting over a distance
work
is the flow of energy caused by a difference in temperature between objects.
Heat
is energy of motion or
energy that is being
transferred.
Kinetic energy
is the energy associated with temperature.
thermal energy
is energy that is stored in an object (e.g. bond energy), or energy associated with the position of the object.
Potential energy
Energy stored in the structure of a compound is
chemical
potential energy.
associated with positions of electrons and nuclei
chemical energy
Kinetic energy associated with the flow of electrical charge
electrical energy
Kinetic energy associated with energy transitions in an atom
Light or radiant energy
Potential energy in the nucleus of atoms
nuclear energy
Potential energy due to the structure of the atoms, the
attachment between atoms, the atoms’positions relative to
each other in the molecule, or the molecules’ relative
positions in the structure
chemical
states that energy
cannot be created nor
destroyed.
law of conservation of
energy
as the material or process within which
we are studying the energy changes within.
system
as everything else with which the system can exchange energy.
surroundings
is the study of the exchange of energy
between the system and the
surroundings.
thermochemistry
that the amount of
energy gained or lost by the system has to be equal to the amount of energy lost or gained by the surroundings.
conservation of energy
is the amount of energy needed to
move a 1 kg mass a distance of 1 meter.
joule (J)
is the amount of energy needed to
raise the temperature of one gram of water 1 o C.
calorie (cal)
is the study of energy and its
interconversions.
thermodynamics
conversion for calorie to joules
1 calorie = 4.184 joules
what is the other name for the law of conservation of energy
The First Law of Thermodynamics
of a system is the sum of the kinetic and potential energies of all of the particles that compose the system.
internal energy (E)
is a mathematical function whose result only
depends on the initial and final conditions, not on the process used.
state function
the height from the base to the peak of the
mountain is a state function
altitude
When energy flows out of a
system, E system is
negative
When energy flows into the
surroundings, E surroundings is
positive
Heat exchange at constant pressure is
called the
enthalpy
are a “graphical”way of showing the direction of energy flow during a process.
Energy diagrams
Energy is exchanged between the system and
surroundings through
heat and work
symbol for heat energy
q
symbol for work energy
w
is the heat capacity.
C
what does the heat of capacity of an object depend on
the mass and the type of material
is the amount of heat energy required to raise
the temperature of one gram of a
substance 1 degree C.
specific heat capacity
is the amount of heat energy required to raise the
temperature of one mole of a
substance 1 degree C.
molar heat capacity
what is work caused by?
a change in volume against an external
pressure
a chemical reaction occurs open
to the atmosphere under conditions of what?
constant pressure
Heat exchange at constant pressure is
called the
enthalpy
device used to measure enthalpy
the coffee-cup caloriemeter
of a system is defined as the sum of the
internal energy of the system (E) and the product of pressure (P) and volume (V):
enthalpy (h)
what is the symbol for enthalpy
H
Hand Ehave the largest difference for reactions that produce or use what
large quantities of gas.
the products of the reaction have less
chemical potential energy than the reactants.
exothermic reaction,
what does a negative delta h mean?
exothermic reaction
what does a positive delta h mean?
endothermic reaction
where does the extra thermal energy come from?
the conversion of
some of the chemical potential energy in the reactants
into kinetic energy in the form of heat.
The enthalpy change in a chemical reaction is an
extensive property
The surrounding area is called a
bomb calorimeter
device used to measure delta E
the bomb calorimeter
why is the the bomb calorimeter used?
bc it has a constant volume system
is the amount of
heat absorbed by the
calorimeter for each degree
rise in temperature
the heat capacity of the calorimeter
heat capacity of the
calorimeter
calorimeter constant.
As something rolls on the table, some of the energy is converted to heat by
friction
is the exchange of thermal energy between a system
and surroundings.
heat
Heat exchange occurs when system and surroundings
have a what?
difference in temperature.
is the measure of the thermal energy within a sample of matter.
temperature
Heat flows from matter with high temperature to matter with low temperature until both objects reach the same
temperature.
Thermal equilibrium
heat flows from the material at the ?
temperature to the material at the ? temperature.
higher to lower
Heat flows until both materials reach the same final
temperature –
Thermal Equilibrium
The amount of heat energy lost by the hot material
equals what?
the amount of heat gained by the cold material.
the change in enthalpy for a stepwise process is the sum of the enthalpy changes of the steps
Hess’s Law
is the enthalpy
change when all reactants and products are in their standard
states.
standard enthalpy change for a reaction
