A. Concepts and Principles of Qualitative and Quantitative Analysis Flashcards
(27 cards)
_____ reveals the identity of the elements and compounds in a sample.
____ indicates the
amount of each substance in a sample.
Qualitative analysis
Quantitative analysis
An ____ is the process of determining how much of a given sample is the material by its indicated name.
assay
The sample MUST be ___ of the population
representative
The ____, is the collection of all of the components in the sample containing an analyte
matrix, or sample matrix
Used in evaporating liquids to remove nitrate ion and nitrogen oxides from acidic solutions
urea
Chloride and nitrate (and other organic constituents) can be removed from a solution by adding ___ and evaporating until copious white fumes of ___ are observed.
This process is called ____
sulfuric acid -> sulfur trioxide
wet ashing
Ammonium chloride is best removed by adding ___ and evaporating the solution to a small volume.
concentrated nitric acid
Ammonium ion can be removed from a liquid by ___
heating - rapidly oxidizes
A ____is the weighing error that develops when the object being weighed has a significantly different density than the masses.
buoyancy error
How to approach this problem?
A bottle weighed 7.6500 g empty and 9.9700 g after introduction of an organic liquid with a density of 0.92 g/cm3. The balance was equipped with stainless steel masses (= 8.0 g/cm3). Correct the mass of the sample for the effects of buoyancy.
- Get the mass of liquid
(m filled - m empty) - d of air = 0.0012 g/mL
d of liquid = 0.92 g/mL
d of masses = 8.0 g/mL - W = W1 + W1 [(0.0012/0.92) - (0.0012/8.0)]
____ is a process in which a solid is cycled through heating, cooling, and weighing steps until its mass becomes constant to within 0.2 to 0.3 mg.
Drying or ignition to constant mass
____ is a process in which a solid moves up the side of a wetted container or filter paper
creeping
____ is a measured fraction of the volume of a liquid sample.
aliquot
Mnemonics for SI units prefixes
The (tera)
Great (giga)
Man (mega)
king (kilo)
henry (hecto)
d(a)ied (deca)
drinking (deci)
chocolate (centi)
milk (milli)
μntil (micro)
nine (nano)
pm (pico)
SI Base units for
1. mass
2. length
3. time
4. temperature
5. amount of substance
6. electric current
7. luminous intensity
- kg
- m
- s
- K
- mol
- A
- cd (candela)
Differentiate mass and weight
Mass m is an invariant measure of the quantity of matter. Weight w is the force of gravitational attraction between that matter and Earth.
w = mg
Value of mole/ Avogadro’s number
6.022 x 10^23
Difference between molar analytical concentration and molar equilibrium concentration
molar analytical concentration Cx- total number of moles of a solute, regardless of its chemical state, in 1 L of solution.
molar equilibrium concentration [X]- the molar concentration of a particular species in a solution.
How to approach this problem?
Calculate the analytical and equilibrium molar concentrations of the solute species in an aqueous solution that contains 285 mg of trichloroacetic acid, Cl3CCOOH (163.4 g/mol), in 10.0 mL (the acid is 73% ionized in water).
- Get the M (mmol/mL) of Cl3CCOOH
- [Cl3CCOO-] = 73% of (M Cl3CCOOH)
- this is also equal to [H+] since 1:1 mole ratio - [Cl3CCOOH] = 27% of (M Cl3CCOOH)
- C of Cl3CCOOH = [Cl3CCOOH] + [Cl3CCOO-] = M of Cl3CCOOH
Differentiate the three %concentration
w/w: (weight of solute/weight of solution) x 100
v/v: (volume of solute/volume of solution) x 100
w/v: (weight of solute in grams /volume of solution in mL) x 100
w/v: g/mL x 100
The only %concentration that is temperature dependent
w/w concentration
(aka mass concentration)
Equalities for ppm, ppb, and ppt
ppt = (mass of solute / mass of solution) x 10^3
ppt = (mass of solute in g / volume of solution in L)
ppt = g/L
ppm = (mass of solute / mass of solution) x 10^6
ppm = (mass of solute in mg / volume of solution in L)
ppm = mg/L
ppb = (mass of solute / mass of solution) x 10^9
ppb = (mass of solute in μg / volume of solution in L)
ppb = μg/L
IMPORTANT: ppt = g/L, ppm = mg/L, and ppb = μg/L are only applicable if densities of solvent is approximately 1.00 g/mL
The p-value is the ___ of the molar concentration of that species.
negative logarithm (to the base 10)
pX = -log [X]
Differentiate density and specific gravity
The density (g/mL) of a substance is its mass per unit volume, and its specific gravity (dimensionless) is the ratio of its mass to the mass of an equal volume of water at 4°C.
