Lesson 3 Flashcards
All chemical reactions exhibits the two
fundamental laws:
the law of conservation of
mass
the law of conservation of energy.
It is defined as the capacity to do
work.
Energy
________, unlike matter, cannot be seen,
touched, smelled, or weighed but all of its
form are capable of doing work.
Energy
directed energy change resulting from
a process.
work
There are different forms of energy namely:
Kinetic energy
Thermal energy
Chemical energy, and
Potential energy
All forms of energy can be ________ from one form
to another, but can neither be _______ nor ___________.
transformed
created
destroyed
In this law, the total quantity of
energy in the universe is assumed constant.
law of conservation of energy
it is the transfer of thermal energy between two bodies
that are at different temperatures
heat
is the study of heat change in chemical
reactions.
thermochemistry
is the specific part of the universe that is of interest to us
system
are the rest of the universe outside the
system.
surroundings
Three types of system:
(a) Open, (b) Closed and (c) Isolated system.
system where it can exchange mass and
energy, usually in the form of heat with its
surroundings.
open system
what system
Example. Boiling soup in an open saucepan
on a stove.
open system
A system that allows the transfer of
energy (heat) but not mass.
closed system
what system?
Example. A pressure cooker on a stove with
its lid tightly closed and the whistle in position
closed system
A system that does not allow the
transfer of either mass or energy.
isolated systm
what system
Example. A thermos flask containing hot
water
isolated
Any energy lost from the system, or the
given reacting mixture, is gained by the
surroundings.
exothermic process
any process
that gives off heat. example: combustion reaction
exothermic
heat has to be
supplied to the system by the
surroundings.
endothermic process
It is the measurement of heat changes.
calorimetry
It is a closed container designed specifically to
measure heat changes.
calorimeter
The ____________ of a substance is the amount of heat
required to raise the temperature of one gram of the
substance by one degree Celsius (J/g·°C).
specific heat (s)
specific heat formula
s=q/(mΔT)
The _____ of a substance is the amount of heat
required to raise the temperature of a given quantity of
the substance by one degree Celsius (J/°C.).
Heat Capacity (C)
Specific heat is an _________ property whereas heat capacity is an
_________ property.
intensive
extensive
The relationship between the heat capacity and
specific heat of a substance is
______,where m is the mass of the
substance in grams.
C = ms
heat change formula
q = CΔt or q = msΔt
+q is for __________ process and -q is for ___________
process.
endothermic
exothermic
Heat of combustion is usually measured by placing a known mass of a compound in a
steel container called a _________________, which is filled with oxygen at
about 30 atm of pressure.
constant-volume bomb calorimeter
is used to determine the heat changes for
non-combustion reactions. They used it in measuring the heat effects of a variety of
reactions such as acid-base
neutralization as well
as Heat of solution and heat of
dilution.
constant-pressure bomb calorimeter
is a thermodynamic quantity equivalent to the total
heat content of a system.
enthalpy
It is equal to the internal energy of the
system plus the product of pressure and volume.
enthalpy
The work is done on the surroundings for an expansion process
and it is done on the system for a compression process.
enthalpy
shows the enthalpy change as well as the
mass relationships. It is essential to specify a balanced equation when
quoting the enthalpy change of a reaction.
thermochemical equations
deals with the interconversion of heat
and other forms of energy.
Thermodynamics
If a reaction does occur under the given
set of conditions is called _________.
spontaneous reaction
If a reaction does not occur under the given
set of conditions is called _________.
nonspontaneous
To determine the spontaneity of the reaction, a
thermodynamic quantity called ________ must be
considered.
entropy
__________is described as a measure of how spread
out or dispersed the energy of a system is among the
different possible ways that system can contain
energy.
Entropy (S)
is the absolute entropy of a
substance at 1 atm and 25°C.
standard entropy
The units of entropy are
______________for 1 mole of the substance.
J/K or J/K·mol
The ____ states that energy can be
converted from one form to another, but it cannot be created or
destroyed.
First Law of Thermodynamics
The ___________ is defined as the entropy
of the universe increases in a spontaneous process and remains
unchanged in an equilibrium process.
Second Law of Thermodynamics
The second law of thermodynamics tells us that a spontaneous
reaction increases the entropy of the universe; that is,
___________
ΔSuniv > 0
In order to express the spontaneity of a reaction more directly, we introduce
another thermodynamic function called __________
Gibbs free energy (G), or simply free
energy
The___________is the free-energy change for a
reaction when it occurs under standard-state conditions.
standard free-energy of reaction (ΔGo)
The ________________ states that entropy of a perfect
crystalline substance is zero at the absolute zero of temperature.
Third Law of thermodynamics
