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Chem 55 Quantitative Analysis Midterm 1 Cheat Sheet (DRAFT) by

chem 55 midterm 1; units, sig fig, uncertainty, propagation, t tests, precision/accuracy, titration, le chat principle

This is a draft cheat sheet. It is a work in progress and is not finished yet.

Units

Exa (E)
Peta (P)
Tera (T)
Giga (G)
Mega (M)
Kilo (k)
Hecto (h)
Deca (da)
^18
^15
^12
^9
^6
^3
^2
^1
Deci (d)
Centi (c)
Milli (m)
Micro (μ)
Nano (n)
Pico (p)
Femto (f)
Atto (a)
^-1
^-2
^-3
^-6
^-9
^-12
^-15
^-18

Sig Figs

Zeros before numbers are not signif­icant. If there is a decimal, zeros after non-zeros are signif­icant.
Multip­lic­ation, division: sig figs based on given value at beginning with least sig figs
+/-: align decimal places and go based off least decimal places. eg: 25.0+1= 26 since 1 has no decimal place
log: for log(x), digits after decimal place= sig figs of x
multi step equation: sig figs based off of last math step you perform

formation constant

uncert­ainty

absolute uncert­ainty= the plusminus value given
relative uncert­ainty= absolute uncert­ainty/ value it is given with
% relative uncert­sinty: abs uncert­ain­ty/­mea­sured value *100
+/- problem: abs uncert­ainty= square root (each abs uncert­ainty squared then added)
mult/d­ivis: convert abs uncert­ainties to % relative uncert­ainties first , do same squaring everything adding all sqrt , at the end undo % by remult­iplying by measured value
sig figs

prop uncert­ainty

  

pH

 
ph+poh=14, ph=-log [h+] so 10^-pH = [H+], poh= -log [oh-] (all log10)
pKa= -log10Ka; HA (aq)⇌ [H+] (aq) + [A −] (aq); ka= [H+][A −]/[HA]

confidence interval

CI= mean +/- ((t from table * stdev)/ sqrt n)
(t table confid­ence%) confidence that the true value is x% away from avg

amino acid structure

F calc

variance 1/vari­ance2

Precision accuracy

 
Precision= stdev/mean x100
relative accuracy= (exper­imental mean- known mean)/­known mean x100, accuracy= (exper­imental mean- known mean)

edta

  

Z stats

 
if given avg and stdev. μ mean, stdev sigma. find range away from mean which will be Z then use table
stdev^2= variance. relative stdev= 100* s/mean. stdev of mean= s/ sqrt n.
z= (x-μ)/­sigma

Equili­brium

Equili­brium

 
K>1=
Ksp, solubility in material= concen­tration of both products multip­lied. AB⇌ [A+] + [B-], ksp= [a][b]
eg: dissolve in solution that is z molarity of y reactant: corres­ponding concen­tration is x+z
solid= always 1

t calc 2 sets of data

EDTA

Mn+ + Ym- = MY ^ (n-m)
EDTA is Y