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Analytical Chemistry
Final Exam Review - 1
42
Chemistry
Undergraduate 2
12/12/2009

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Term
Molarity (M)
Definition
mol / L total solution
Term
Molality (m)
Definition
mol solute / kg solvent
Term
weight %
Definition
(mass analyte / total mass) x 100
Term
ppm
Definition
mg / L

(mass analyte / mass tot soln) x 10^6
Term
ppb
Definition
(mass analyte / mass tot soln) x 10^9
Term
ppt
Definition
g / L

(mass analyte / mass tot soln) x 10^3
Term
Schlieren Effect
Definition
indicies of refraction cause a solution to look oily if it is not well mixed
Term
Bad Primary Standards
Definition
-Na2CO3
-H2SO4
-HCl
Term
Systematic Errors (Determinate)
Definition
reproducable
Term
Random Errors (Indeterminate
Definition
Gausian disstribution
Term
Accuracy
Definition
how close to the correct value
(error)
Term
Precision
Definition
how consistent you are
(deviation)
Term
absolute error
Definition
mean -actual value
Term
Relative Error
Definition
actual error/ actual value
Term
absolute deviation
Definition
result - mean
Term
Average Deviation
Definition
(∑|x-mean|)/ N
Term
Rel. Avg. Dev.
Definition
[(∑|x-mean|)/ N ] / mean
Term
Std. Dev.
Definition
√ {[∑(x – mean)^2] / N-1}
Term
aA + bB --> cC + dD
Find Keq
Definition
[C]^c x [D]^d / [A]^a x [B]^b
Term
Combine
H2CO3 --> H+ + HCO3- Keq1
HCO3- --> H+ + CO32- Keq2
Definition
H2CO3--> 2H+ + CO3 2-
Keq = (Keq1)(Keq2)
Term
Reverse:
H2CO3 --> H+ + HCO3-
Keq1 = 4.45x10^-7
Keq = (Keq1)(Keq2)
Definition
HCO3- + H+ --> H2CO3
Keq= 1/Keq1 = 2.25x10^6
Term
Order of precipitation
Definition
smaller Ksp precipitates first
Term
Common Ion Effect
Definition
a salt will be less soluble if one of its constituent ions is already present in the solution
Term
Acids and Bases
Arrhenius
Bronsted-Lowry
Lews
Definition
H+ and OH-
H+ donar and H+ acceptor
e- acceptor and e- donar
Term
Strong Acids
Definition
HCl
HNO3
H2SO4
HClO4
HBr
HI
Term
Weak Acids
Definition
HOAc
Carboxylic Acids
HF
H2S
H3PO4
H2CO3
Term
Strong Bases
Definition
NaOH
KOH
LiOH
Term
Weak Bases
Definition
NH3
R-NH2
Term
Find Kb
NH3 + H2O --> NH4+ + OH-
Definition
Kb = [NH4+]x[OH-] / [NH3]
Term
Kjeldalhl For N
(volumetric)
Definition
-sample placed in boiling H2SO4--> NH4+ + CO2 + H2O
-add excess base to convert NH4+ --> NH3
-distill the NH3 into a known conc. of HCl (some of the HCl will be neutralized, but not all)
-titrate the excess HCl with NaOH
-the difference in moles correlates to the moles of NH3 consumed
Term
What is the end point?
Definition
observed in lab --> color change
Term
What is the equivalence point?
Definition
mol of titrant = mol of anlayte
Term
ionic strength
Definition
1/2 ∑CnZn^2 = µ
C=Concentration
Z=Charge
Term
Activity of M
Definition
ÂM = [M]γM
Term
Debye- Huckle Equation
(for calculating γ)
Definition
logγ = (-0.51 x z^2√µ) / (1 + {[α√µ]/305})
γ = activity coefficient
z = ion charge
µ = ionic strength in [M]
α = hydrated ionic raiums in ppm
Term
Thermal Expansion
Definition
(conc1/ dens1) = ( conc2/ dens2)
[M]( 1 ± coeff. of therm. expan)(∆ temp)=
Term
Comparing an answer with the accepted answer within a specified confidence limit of a small data set (replication of a measurement with one overall mean and standard deviation)
Definition
Use the Confidence Interval:
µ = [m ± (ts)] / √n
look up t value for whatever degrees of freedom your data has (df = n-1)
Term
Comparing two different methods to see whether they agree with each other within a specified confidence limit. Measuring a qunatity multiple times with different methods; each data set has its own mean and standard deviation.
Definition
tcalc = |m1-m2| / spooled
calculate this t and compare to a t value from the table
Term
Comparing whether 2 methods agree with each other when a sample is measured once by one method and then again by another. Then different sample is measured once by method 1 and once by method 2. This is repeated for n different samples
Definition
1.Standard Deviation of the differences:
sd=√( [∑ (di - d)^2] \ n-1 )
di=difference between two methods
d= mean of the differnces
2. tcalc=(|d|/sd) √ n
Term
variance
Definition
s^2
(s=std. dev)
Term
coefficient of variation
(relative standard deviation)
Definition
(s/m) x 100
Term
Standard Error of the Mean
Definition
s / √n
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