CHEM 2080: Prelim 1
76 Cards in this Set
| Front | Back |
|---|---|
|
1 atm = ? Torr = ? Psi
|
760 Torr = 14.7 psi
|
|
When using concentrations, what reactants cannot be used?
|
Solids
|
|
Define work
|
transfer of energy involves the action of a force through a distance
|
|
Define heat
|
occurs when there is a temperature difference between system and surroundings
|
|
Define enthalpy
|
energy required to contract or expand against a constant external pressure
|
|
Properties of molar enthalpy
|
state function and additive
|
|
Define standard molar enthalpy of formation
|
the enthalpy change for the equation in which one mole of a compound is formed at one-bar in stable forms of elements
|
|
Define heat capacity
|
energy in the form of heat required to raise the temperature of the sample by one degree
|
|
Define specific heat capacity
|
energy in the form of heat required to raise the temperature of a mass of a sample by one degree
|
|
Define half-life
|
the time it takes for one-half of a quantity of a reactant to react
|
|
The rate of reactants colliding correspond to…
|
the concentration dependence
|
|
The probability of having enough energy to react corresponds to…
|
temperature dependence
|
|
To maximize the rate of reaction, maximize the…
|
rate of A-B collisions
|
|
The rate of A-B collisions is proportional to the…
|
concentrations of A + B
|
|
Molecular energy diagrams are used to represent…
|
the total energy of the molecule
|
|
The total energy of the molecule is constant unless…
|
there is energy transfer
|
|
Potential energy is stored…
|
in bond
|
|
The kinetic energy is the…
|
veolcity
|
|
Define activation energy
|
Minimum energy needed for reaction
|
|
Temperature controls…
|
the average speed of molecules
|
|
If work is positive…
|
system gains energy e.g. compression
|
|
If work is negative…
|
system loses energy e.g. expansion
|
|
If heat is positive…
|
heat is transferred from the surroundings to the system
|
|
positive heat is what kind of reaction?
|
endothermic
|
|
If heat is negative…
|
system releases heat into the surroundings
|
|
negative heat is what kind of reaction?
|
exothermic
|
|
State functions depend on…
|
the state of a system, not the pathway it took
|
|
State functions
|
Enthalpy and energy
|
|
Pathway functions
|
q and w
|
|
A bomb calorimeter has a fixed…
|
volume
|
|
No work is done in a…
|
bomb calorimeter
|
|
All monatomic gases have a Cp of…
|
20.8 J/(mol K) at 25 degrees celsius
|
|
Regarding the size of the molecule and heat capacity, what features do polyatomic molecules have?
|
The larger the molecule, the more it can move, this the higher heat capacity
|
|
The half-life of a second-order reaction depends on…
|
initial concentration
|
|
Define an intermediate species
|
does not appear in the overall equation for the reaction
|
|
An intermediate species is produced…
|
in one step and consumed in the next
|
|
Bimolecular reactions include…
|
two molecules
|
|
Termolecular reactions include…
|
three molecules
|
|
Unimolecular reactions include…
|
one molecule
|
|
Temperature has a huge effect on…
|
rate of reaction
|
|
Within a piston, heat does not change…
|
pressure within the system
|
|
If the piston rises, work is…
|
negative
|
|
In a piston, there is constant…
|
pressure
|
|
For a piston, some energy can be released to…
|
surroundings as work
|
|
In a bomb, there is no…
|
work
|
|
If no work can be done, heat is transferred to…
|
the hand
|
|
In a graph, the reaction rate is calculated from…
|
the absolute value of a slope of concentration vs. time
|
|
If the graph of concentration change is straight, than the rate of reaction = …
|
k
|
|
If a graph of concentration change is straight, than the rate of reaction is independent of….and what order?
|
Concentration and zero order
|
|
For rate laws, the number of experiements needed to determine the rate law is equal to…
|
the number of unknowns in the equation
|
|
To determine the order of the reaction, graph…
|
the change in concentration against time
|
|
Concentration-independent half-life implies…
|
a first order reaction
|
|
Highest rate corresponds to…
|
highest number of collisions
|
|
When rate is independent of concentration, doubling the concentration should not effect…
|
the rate
|
|
Pressure can be substituted for…
|
concentration
|
|
In a piston, make sure to check….
|
weights on the piston
|
|
heat of formations is subject to…
|
coefficients
|
|
Equation to plot time against reaction rate
|
|
|
...
|
|
|
...
|
|
|
To find α and β for experiments that don't have 1 constant concentration
|
Rate1/[A]α1[B]β1 = Rate2/[A]α1[B]β2
|
|
Plot of 1/[A] is linear for...
|
a second-order reaction
|
|
Units of k for a first-order reaction is...
|
1/h
|
|
log ax = ...
|
x log a
|
|
ln(a/b) = ...
|
ln a - ln b
|
|
units of work
|
Joules (kg⋅m2/s2)
|
|
Units of heat (q)
|
Joules (kg⋅m2/s2)
|
|
Units of ΔHrxn
|
Joules (kg⋅m2/s2)
|
|
Units of ΔUrxn
|
Joules (kg⋅m2/s2)
|
|
Molar gas constant, R = ...
|
8.3145 m2⋅kg/(s2⋅K⋅ mol)
|
|
Δνgas = ...
|
(sum of coefficients of gaseous products) - (sum of coefficients of gaseous reactants)
|
|
Units of ΔH°rxn
|
kJ/mol
|
|
units of cp
|
J/K
|
|
units of Cp
|
J/(mol⋅K)
|
|
units of csp (specific heat capacity)
|
J/(g⋅K)
|
|
Units of Ea
|
J/mol
|
CHEM 2080: Prelim 1