Final Exam (not including exams 1-3) Flashcards
energy
capacity to do work
heat
transfer of energy from higher temerpature to lower temperature
thermodynamics
study of heat and energy flow during change and the relationship between heat and work
thermochemistry
study of heat involved in chemical and physical changes
or
study of heat change in chemical rxns
explosion energy (examples)
light, heat, sound, gas, expansion (work)
What does each particle in a system have?
kinetic and potential energy
internal energy (E)
kinetic + potential energy
joule
amount of energy needed to lift a 1 kg mass by 1 meter
calorie
amount of energy needed to raise 1 gram of water by 1 degree celcius
system
part of the universe that is of interest in the study
* can be anything
* ex. a person, a room
universe
system+surroundings
what can be exchanged in an open, closed, and isolated system
open: mass and energy
closed: energy
isolated: nothing
kinetic and potential energy are ___
inconvertable (not able to be changed)
law of conservation of energy
energy cannot be created or destroyed; it is constant
state functions
properties that are determined by the current state of the system, regardless of the path taken to reach that state
ex. energy, pressure, volume, temperature
analogy: 2 hikers took different paths but ended up at the same spot
first law of thermodynamics
energy can be converted from one form to another but cannot be created or destroyed
heat in an exothermic rxn
heat goes from (lost from the) system to surroundings
what are the 2 ways energy is lost from a system
- converted to heat, q
- used to do work, w
work
energy transferred when something is moved by a force acting over a distance
when gases expand, change in volume is ___, but the system is doing work on the surrounding, so work is ___
positive
negative
exothermic process
heat goes from system to surroundings
endothermic
heat goes from surroundings to system
standard enthalpy of formation of any element in its most stable form is ____ degrees celcius
0
hess’s law
the enthalpy change for an overall process is the sym of the enthalpy changes for the individual steps
kinetics
how fast will the rxn proceed
how does spontaneity have to do with speed
nothing
spontaneous change
occurs without a continuous input of energy from outside the system
* leads to an increase in entropy
nonspontaneous change
occurs if the surroundings continuously supply energy to the system
if a change is spontaneous in one direction, it will be ____
nonspontaneous in the reverse direction
spontaneous process
occurs under a specific set of conditions
nonspontaneous process
does not occur under a specific set of conditions
entropy (S)
measure of how spread out or how dispersed the system’s energy is
* increases when volume is larger
4 processes that lead to an increase in entropy
- melting
- vaporization
- temp. increase
- greater number of gas molecules
does entropy increase or decrease with temperature
increases
higher entropy when…
- molecules are more complex
- molecules are larger
- more energy
- higher temp
- solid to liquid to gas
which has a higher entropy: dissolved solid or liquid vs pure substance
dissolved
which has a higher entropy: gas dissolved in solution and solid vs pure gas
pure gas
entropy (S) is a measure of how ___
dispersed energy is throughout the system
2nd law of thermodynamics
no process is 100 efficient
heat lost to surroundings
standard free energy of rxn
free energy (G) change for a rxn wehn it occurs under standard-state conditions
standard state conditions
temp = 298 K
pressure = 1 atm
[solute] = 1.0 M
[H+] = 1 M
what does change in free energy tell us
spontaneity and the maximum energy available to do work
delta G
change in free energy when pure reactants convert COMPLETELY to pure products
what is the keq for product favored rxns
keq>1
conditions for reactant favored
change G under standard conditions>0 and K<1
oxidation
loss of electrons
reduction
gain of electrons
oxidizing agent
thing that is reduced
reduction agent
thing that is oxidized
oxidation number
charge the atom would have in a molecule or compound if electrons were completly transferred
anode
the electrode at which oxidation occurs
cathode
the electrode at which reduction occurs
does the anode or cathode produce the electrons
anode
salt bridge
spectator counter ions flow through the salt bridge to keep net neutral charge in the solutions
anode is always on the left or right
left
conditions for standard reduction potential (E naught)
1 M and 1 atm
E naught
sign changes when half-cell rxn is reversed but the number does not change even when coefficients do
diagonal rule
species on left with react spontaneously w/ species on the right of any rxn located below it
diagonal rule in my own words and applied to the problem
an element on the left side and above the other element is the one that gets reduced; the other element gets oxidized so we flip its equation and the E naught sign
when to use subscripts vs coefficients from balance equation
subscripts - breaking a moelcule into its individual element
coefficients - moles of reactant or product into moles of another
diatomic molecules molar mass
just one - when it’s apart of a compound
two - when it is alone
