Exam 3 Flashcards
redox reaction
- involve transfer of electrons
- involve change in oxidation states
easily identifiable redox reactions
- combustion
- metal –> ionic compound
oxidation
loss of electrons
reduction
gain of electrons
True of False: oxidation and reduction can happen independently
FALSE. LIES.
reducing agent
- contains the thing being oxidized (whose charge increases)
- electron donor
oxidizing agent
- contains the thing being reduced (whose charge decreases)
- electron acceptor
Free element oxidation number
0
simple ion oxidation number
ion charge
sum of oxidation numbers
= the overall charge
F oxidation number
-1
H oxidation number
+1 (except with metal hydrides when it is -1)
O oxidation number
-2 except in peroxides when it is -1)
kinetic energy
energy of motion
KE =
1/2mv^2
Potential Energy
energy due to an object’s position or arrangement of its parts
Calorie to Joule
1 Calorie = 4.184 J
Heat
transfer of thermal energy
thermal equilibrium
when two or more substances in contact with one another reach the same temperature
internal energy (E or U)
- the sum of the energies in an individual particle of matter
molecular kinetic energy
KE of/ within molecules as they move
Change in Energy =
E final - E initial
Change in Energy is +
if a system absorbs energy from its surroundings
temperature vs. internal energy
- temperature is average KE
- internal energy is TOTAL molecular KE
temperature and kinetic energy are
directly proportional
state of an object
list that specifies objects current condition
state function
property that depends SOLEY on the current state of an object
open system
can gain or lose mass and energy
closed system
can gain or lose energy, NOT mass
isolated system
cannot gain or lose energy or mass
heat equation: q=
C (delta t)
heat capacity
the amount of heat required to raise an object 1 degree C
C =
(mass)(specific heat)
specific heat
amount of heat required to raise 1 g of a substance 1 degree C
heat absorbed/released: q=
ms (delta t)
chemical bond
the net attractive force between two atomic nuclei
when chemical bonds are formed, energy is….
RELEASED
chemical energy
P.E. of chemicals transferred in reactions
exothermic
heat is a product
endothermic
heat is a reactant
heat of reaction
amount of energy absorbed or released in an rx
pressure =
force / area
atmospheric pressure
- pressure from the atmosphere
- 14.7 lb/ in ^2
- around 1 amt
- around 1 bar
qv
heat at constant volume
qp
heat at constant pressure
P-V work: w =
P (delta V)
P-V Work
energy transferred as system expands or contracts against surrounding pressure
First Law of Thermodynamics
- conservation of energy
- delta E = q + w
q and w are….
NOT state functions
Delta E is a….
state function
heat of combustion
- heat produced by a combustion rx
- measured in a closed container
#bombcalorimeter
Bomb Calorimeter
measures the heat of rx under @ constant volume
heat of rx in solution are measured by
constant pressure calorimetry
delta H =
qp
delta H (in terms of H) =
H final - H initial
H product - H reactant
H =
E + PV
Positive delta H
endo
Negative delta H
exo
Enthalpy
heat content of a system
H
standard heat of reaction
value of delta H for a reaction under standard conditions and an actual number of moles (coefficients)
Hess’s Law
for reactions that can be written in steps, delta H is the sum of the delta H’s from the steps
