Boon Cume Flashcards
(105 cards)
Henderson-Hasselbach
pH = pKa + log([A-]/[HA])
All terms
pH is pH of solution ( unitless log concentration of H+ in aqeous solution (estimate of buffer solution))
pKa is pKa of our acid in question - acid dissociation constant of acid (unitless)
[A] is concentration fo conjugate base (concentration needs to be same as HA but typically M)
[HA] is concentration of acid - concentration M
Importance: allows a quick way to determine pH of weak acid solution - derived from Ka
also allows us to quickly make buffers of certain pH’s or determine how to make a solution of a certain pH with a weak acid or base
Nernst Equation
E cell = E(naught)cell -(RT/nf)ln(Q)
E cell - is potential of a cell at non standard conditions (V)
E naught cell is potential of cell at standard state conditions
R is the ideal gas constant - will change with units standard 8.314 - J/(mol *K)
T is temperature in Kelving
n is # of moles of electrons in balanced equations (transferred in redox) - unitless
F is Faradays constant (95,458.56 C/mol or 96,000)
Q reactant quotient or products/reactants - unitless? or has units depending on rate
Used for determining electrical cell potential under non standard conditions
Also relates our thermodynamic equations to our cell potential equations G = -RTln(K) - there are 2 others
Ohms Law
V = IR
Voltage (in V)
I is current (in amps)
R is resistance (in ohms)
Very fundamental relationship in electronics movement of electrons
Current through conductor proportional to voltage across two points
Thermal Noise in a resistor
Vrms = ROOT(4Kb * T * R * DELTA(F))
Vrms= root mean square noise voltage in V
Kb is Boltzmann constant – 1.38E-23 which is J/K)
T is temp in kelvin
R – Resistance of Element (ohms)
Delta F – is Frequency Bandwidth (Hz)
Signifigance: Thermal Johnson Noise – refers to the noise of thermal agitation of electrons in circuits – As such only disappears at absolute 0 and is a constant baseline noise -important in instrument detector readout. Frequency independent
An application – can reduce our noise by lowering temperature, reducing resistance, narrowing the bandwidth of electronic components of our detector
Biomolecular Reaction Rate
r = k[A][B] for A+B -> P
R = reaction rate (M/s)
K = reaction rate constant (2nd order so 1 /(M*s))
[A] and [B] are the concentration of reactants in Molarity
Signfigance – describes rate of chem reaction
Upper limit defined by frequency of collisions (eg limited by diffusion)
Arrhenius Equation
k = Ae^(-Ea / RT)
K is the rate constant – depends on rate order (1/s for first order?)
A is pre-exponential factor which can be broken down into frequency factor and orientation – also 1/s)
Ea is activation energy (J/mol)
R is gas constant 8.314 – J/(Kmol)
T is temp in kelvin
Signifigance: important factors that determine the rate of equationa dn show how we can manipulate the conditions to increase our rate (eg increase temperature)- also allows us to specifically calculate activation energy
Half lfie for first order reaction
t(1/2) = ln(2)/k
T ½ is the half life in seconds
K is the reaction rate (so first order 1/s)
Important because is an easy equation to get the half life of a reaction
Derived from first order rate equation
Half life time it takes to reach ½ fvalue (of reactant)
Fick’s Law of Diffusion 2 of them
1st)
J = -D(dn/dx)
2nd law )
dn/dt = D (LAPLACE(n(x,t)))
J is diffusion flux (m^2 * s)
D is diffusion coefficient (m^2/s)
N is concentration (mol/m^3)
X is position (m)
Delta here is laplace operator
T is time (s)
Signifigance: 1st law describes diffusion of a mixture in solution (from high to low concentration with magnitude proportional to concentration gradient)
2nd law – predicts how diffusion changes over time – using a partial differential equation . Used to model transport
Snell’s Law
nsin(theta) = nsin(theta)
N is the refractive index of a medium (unitless)
Theta is an angle between llight and normal (degrees)
Describe refraction of light moving through different media
Important in microscopy and spectroscopy
Indices = to reciprocal of phase velocities (so n2/n1 = v1/v2)
FRET efficiency
E = 1/(1 + r /Ro)^6)
E – efficiency – unitless
R – donor to acceptor distance (nm)
Ro = Forster distance (distance at which energy transfer efficiency is 50% related to overlap of donor and acceptor emission spectrums and molecular orientation – in nm)
Quantum yield of energy transfer – Efficiency dramatically decreases as afunction of distance (we see to the 6th power)
Important for describing molecular chromophores – useful for bio and chemical sensors
Energy of Molecular Vibration eg energy spacing
E = h(n+ ½)v
E is energy at specified state (j)
H is plancks constant (6.626 E-34) Js
N is quantum number (unitless)
V is frequency (1/s)
This approximates molecular energy fo a vibrational state when using a simple harmonic oscillator approximation
Useful in molecular spectroscopy for interpreting spectra
Van Deemter
HETP = a + B /u+ c*u
HETP is height in theoretical plates (it’s a number of plates – related to resolution – is mm)
A is eddy diffusion term – (multi path effect) in mm
B is Band Broadening term – longitudinal diffusion (as something goes through a path it naturally spreads out in mm
C is mass transfer (the peak broadening that occurs as something moves across phases) in mm (diffusion into MP pores)
U is linear velocity (mm/s)
Signifigances – used to demonstrate efficiency for chraomtography columsna nd used to make them more efficient
Relates plate height to velocity of mobile phase by considering aspects of diffusion during separation – can be used to minimize HETP to maximize resolution
Equation relating Gibbs free energy to Equillibrium constant
Delta G(naught) = -RTln(K)
Gibbs free energy at standard state (kj/mol)
Gas constant (8.314 – J/mol*K)
Temperature, Kelvin
And K – equilibrium constant (depends on rate)
Relates gibbs free energy to our equilibrium constant
Equation relating Gibbs free energy to standard state potential of cell
Delta G = -nfE(naught)cell
G is gibbs free energy kJ/mol
N is moles of electorns transferred in balanced equation
F is faradays constant (96,000) C/mol)
E cell – is potential at standard state (V)
Relates gibbs free energy to an voltaic cell
Gibbs free energy equation
G = H TS
note (delta G, H and S)
Change in Gibbs free energy (kj/mOl)
= change in enthalpy (kj/mol)
- Temperature (Kelvin)
- Times Entropy (J/mol)
Very fundamental key equation relating gibbs free energy to enthalpy and entropy – demonstrates the energy available in a system to do work and what that depends on and how we can manipulate that by manipulating H or entropy.
Also can indicate spontaneity of a reaction (gibbs free energy <0)
Strength of electric field
E = F/q
E being strenght of electric field in N/C or volts/m
F being force exerted on an ion - force in Newtons
and q being the charge of the ion - charge in Coulombs
Lorentz Force Law
F = qE + qvxB
E being strenght of electric field in N/C or volts/m
F being force exerted on an ion - force in Newtons
and q being the charge of the ion - charge in Coulombs
v is velocity m/s
B is magnetic field in T
note vxB is the cross product
can also be qvbsin(phi)
with phi beingthe angle between v and B
Ohms Law
V = IR
Voltage (in V)
I is current (in amps)
R is resistance (in ohms)
Very fundamental relationship in electronics movement of electrons
Current through conductor proportional to voltage across two points
Light equation
c = Lambda * frequency
c being m/s
Lambda being m and frequency being 1/s
(can also have waveneumber - recipricol of wavelength
Energy of electromagnetic radiation
E = hv = hc/lambda = hwavenumber
E is energy in joules
wavelength in nm m etc
frequency 1/s (or wavenumber 1m
c is speed olight m/s
h is plancsk constant 6.634 E - 34 JS
Apparent Transmittance
(P + S)/ (P0 +S)
with P being radiation power exiting sample
P0 being initial radiation
and S being stray light
all unitless
important because transmittance and absorption key for spectrochem
Intensity of Phosphorescence/Fluorescence
Ip = 2.303 * k * phi(p) * (epsilon) *b * C *P(naught) = k’ * P(naught)
Note this is the same s fluorescent or the other equation but just has a k as well
phi(p) is the phosphorescent quantum yield (the fraction of exicited state molecules that return to ground state through phosphorescence (0-1)
k is a constant that accounts for efficiency in collecting and detecting emissions
C is concentration (M)
erpsilon is molar absorptivity (1/cm*M)
b is path length (cm)
P0 is the inital radiation pre sample
k’ is a constant that combines the other constants to simplify the equation
Note fluroescence equation is the same
Turbideemetry equation
T = It/Io
-log(T = kbC - same idea as a beers law
LOD expressions
3.3 * Sa/b)
LOQ = 10 *Sa/b
S being standard deviation of response or a blank
and b being the slope of the regression line
importance in being a standard way LOD and LOQ is made when describing a method and circumscribing its capabilites