N THERMODYNAMICS
First law of thermodynamics: Energy Conservation Law
Thermodynamics is the study of energy and its transformations.
Mainly associated with heat, energy and temp
Energy can’t be created nor destroyed. Total universal energy is constant.
Energy can only ever be converted from one form to another/ or
transferred between systems.
Internal energy:
State functions: Path functions:
Bond enthalpies Heat
Internal energy and enthalpy Work
Heat capacity and specific
heat
Calorimetry
Hess’ law
Enthalpies of formation
ΔE Change in internal energy. Issa state function so its value depends
on the current state of the system rather than the end state.
q (heat) Energy transferred due to temp diff
+q Heat is absorbed by system (endothermic)
-q the opposite, heat released
W (work) Energy transferred by a force acting over a distance.
+W Work is done ON system (compressing a gas for eg)
-W Work is done BY system (gas expanding for eg)
SPONTANEITY, REVERSIBILITY AND ENTROPY:
Spontaneous reactions:
Reactions that can occur without any outside help. They happen on their
own and are irreversible.
For eg: Gas spontaneously expands into an evacuated space. It will not
spontaneously all go back into one corner.
These reactions tell direction (will it happen) not speed.
, Spontaneous reactions are temperature dependent. Meaning, a process
can be spontaneous at one temp and non-spontaneous at another.
Like how ice melts spontaneously at 0+ C but not at <0 C
Reversible vs Irreversible reactions:
Reversible reaction Idealised, infinitely slow process where
system and surroundings can be restored to OG state by
infinitesimal reversal of conditions.
Irreversible reactions Real world, finite-time process that can’t
be undone without permanent change in universe. ALL
SPONATANOUES REACTIONS ARE IRREVERSIBLE
Entropy: Measure of disorder
State function that measures disorder/randomness of system. Related to
how energy + molecules can be arranged.
S Entropy
q heat transferred under reversible conditions
T temperature in Kelvin
2ND AND 3RD LAWS OF THERMODYNAMICS
First law of thermodynamics: Energy Conservation Law
Thermodynamics is the study of energy and its transformations.
Mainly associated with heat, energy and temp
Energy can’t be created nor destroyed. Total universal energy is constant.
Energy can only ever be converted from one form to another/ or
transferred between systems.
Internal energy:
State functions: Path functions:
Bond enthalpies Heat
Internal energy and enthalpy Work
Heat capacity and specific
heat
Calorimetry
Hess’ law
Enthalpies of formation
ΔE Change in internal energy. Issa state function so its value depends
on the current state of the system rather than the end state.
q (heat) Energy transferred due to temp diff
+q Heat is absorbed by system (endothermic)
-q the opposite, heat released
W (work) Energy transferred by a force acting over a distance.
+W Work is done ON system (compressing a gas for eg)
-W Work is done BY system (gas expanding for eg)
SPONTANEITY, REVERSIBILITY AND ENTROPY:
Spontaneous reactions:
Reactions that can occur without any outside help. They happen on their
own and are irreversible.
For eg: Gas spontaneously expands into an evacuated space. It will not
spontaneously all go back into one corner.
These reactions tell direction (will it happen) not speed.
, Spontaneous reactions are temperature dependent. Meaning, a process
can be spontaneous at one temp and non-spontaneous at another.
Like how ice melts spontaneously at 0+ C but not at <0 C
Reversible vs Irreversible reactions:
Reversible reaction Idealised, infinitely slow process where
system and surroundings can be restored to OG state by
infinitesimal reversal of conditions.
Irreversible reactions Real world, finite-time process that can’t
be undone without permanent change in universe. ALL
SPONATANOUES REACTIONS ARE IRREVERSIBLE
Entropy: Measure of disorder
State function that measures disorder/randomness of system. Related to
how energy + molecules can be arranged.
S Entropy
q heat transferred under reversible conditions
T temperature in Kelvin
2ND AND 3RD LAWS OF THERMODYNAMICS
