1. Brief review of important concepts for quantitative analysis
CHM 235 – Dr. Skrabal
Brief review of important concepts for quantitative analysis
Some important units of quantification
Units for expressing concentrations in solids and liquids
Concentration-dilution formula

2. Fundamental SI units Remember the correct abbreviations! Mass
kilogram (kg)
Volume
liter (L)
Distance
meter (m)
Temperature
kelvin (K)
Time
second (s)
Current
ampere (A)
Amount of substance
mole (mol)
Luminous intensity
candela (cd)

3. Some other SI and non-SI units
Length
angstrom (Å)
Force
newton (N)
Pressure
pascal (Pa), atmosphere (atm)
Energy, work, heat
joule (J)
Power
watt (W)
Electric charge
coulomb (C)
Electric potential
volt (V)
Electric resistance
ohm ()
Electric capacitance
farad (F)
Temperature
degree Celsius (°C)
degree Fahrenheit (°F)

4. Some common prefixes for exponential notation
1012
tera (T)
109
giga (G)
106
mega (M)
103
kilo (k)
10-1
deci (d)
10-2
centi (c)
10-3
milli (m)
10-6
micro (μ)
10-9
nano (n)
10-12
pico (p)
10-15
femto (f)
10-18
atto (a)
Remember the correct abbreviations!

5. Commonly used equalities
103 mg = 1 g milli = thousandth
1 mg = 10-3 g
106 μg = 1 g micro = millionth
1 μg = 10-6 g
109 ng = 1 g nano = billionth
1 ng = 10-9 g
1012 pg = 1 g pico = trillionth
1 pg = g

6. Concentration scales Molarity (M) = Molality (m) =
Molarity is a temperature-dependent scale because volume (and density) change with temperature.
Molality is a temperature-independent scale because the mass of a kilogram does not vary with temperature.

7. Concentration scales (cont.)
Formality (F) =
Formality is sometimes used to express the concentration of substances, such as electrolytes, acids, and bases, that turn into different species in solution.
For example:
0.1 M NaCl (= 0.1 F NaCl) gives 0.1 M Na+ and 0.1 M Cl- in solution
0.5 M HCl (= 0.5 F HCl) gives 0.5 M H+ and 0.5 M Cl- in solution

8. Concentration scales (cont.)
Weight / weight (w/w) basis
% (w/w) =
ppt (w/w) =
ppm (w/w) =
ppb (w/w) =
 percent
 ppt = parts per thousand
 ppt = parts per million
 ppt = parts per billion
 ppt = parts per trillion
This scale is useful for solids or solutions.

9. Concentration scales (cont.)
Weight / volume (w/v) basis
% (w/v) =
ppt (w/v) =
ppm (w/v) =
ppb (w/v) =
 percent
 ppt = parts per thousand
 ppt = parts per million
 ppt = parts per billion
 ppt = parts per trillion

10. Concentration scales (cont.)
Volume / volume (v/v) basis
% (v/v) =
ppt (v/v) =
ppm (v/v) =
ppb (v/v) =
 percent
 ppt = parts per thousand
 ppt = parts per million
 ppt = parts per billion
 ppt = parts per trillion

11. Concentration examples
Concentrated HCl
Alcoholic beverage
Color indicator for titrations

12. Concentration example: %(w:v)
What is the concentration, on a %(w:v) basis, of vanadium in a solution that contains mg/L of vanadium?

13. Concentration scales (cont.)
Parts per million, billion, trillion are very often used to denote concentrations of aqueous solutions:
Note: ppt = parts per trillion

14. Concentration scales (cont.)
It is important to memorize:
1 part per million (ppm) = 1 mg / L
1 part per billion (ppb) = 1 μg / L
1 part per trillion (ppt) = 1 ng / L

15. Concentration examples
Conversion of molarity to ppm
Solution of M K2SO4

16. Concentration examples
What is concentration (in ppm) of K+ in this solution?
Solution of M K2SO4

17. Concentration-dilution formula A very versatile formula that you absolutely must know how to use
C1 V1 = C2 V2
where C = conc.; V = volume
M1 V1 = M2 V2
where M = molarity
Cconc Vconc = Cdil Vdil
where “conc” refers to the more concentrated solution and “dil” refers to the more dilute solution. Note that you can use any units you want for conc. and vol. as long as they are the same on both sides of the equation.

18. Concentration-dilution formula example
Problem: You have available 12.0 M HCl (conc. HCl) and wish to prepare L of M HCl for use in an experiment. How do you prepare such a solution?
Cconc Vconc = Cdil Vdil
Write down what you know and what you don’t know:

19. Concentration-dilution formula example
Problem: You have available 12.0 M HCl (conc. HCl) and wish to prepare L of M HCl for use in an experiment. How do you prepare such a solution?
Cconc Vconc = Cdil Vdil
Cconc = 12.0 mol L-1 Cdil = mol L-1
Vconc = ? Vdil = L
Vconc = (Cdil)(Vdil) / Cconc
Vconc = (0.750 mol L-1) (0.500 L) / 12.0 mol L-1
Vconc = 3.12 x 10-2 L = 31.2 mL

20. Concentration-dilution formula example
Great! So how do you prepare this solution of M HCl?
Use a pipet or graduated cylinder to measure exactly 31.2 mL of 12.0 M
Transfer the 31.2 mL of 12.0 M HCl to a mL volumetric flask
Gradually add deionized water to the volumetric flask and swirl to mix the solution
As the solution gets close to the mL graduation on the flask, use a dropper or squeeze bottle to add water to the mark
Put the stopper on the flask and invert ~20 times to mix