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Experiment 9

Groups 9, 10, 11

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` Qualitative inorganic analysis is the part

of analytical chemistry which seeks to

establish elemental composition of

inorganic compounds by using various

reagents.

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` It is mainly focused on detecting ions in an

aqueous solution, so materials in other

forms need to be brought into this state

before using standard methods.` The aqueous solution is then treated with

various reagents to test for reactions

characteristic of certain ions which result

in color change, solid formation, etc.

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` Ions are removed in groups from the initial

aqueous solution. After each group has

been separated, then testing is conducted

for the individual ions in each group.

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` Analytical chemistry is a category of chemistry

with a broad mission of understanding the

chemical composition of all matter and developing

the tools and experiments to make qualitative orquantitative measurements.

` 2 Types:

a. Qualitative Analysis

b. Quantitative Analysis

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` Traditionally, it was concerned with what

chemicals are present, what their characteristics

are, and in what quantities they are present

` These questions are often involved in questionsmore dynamic such as what chemical reaction an

enzyme catalyzes or how fast it does it, or even

more dynamic such as what is the transition state

of the reaction

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` Solubility test

` Centrifugation

`

Decantation` Flame test

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` This procedure is employed using both dilute and

concentrated forms of HCl, HNO3, H2SO4, and

aqua regia. (In Expt. 9, 6M HCl, 6M HNO3,

concentrated HCl and HNO3, and aqua regia)` In most cases, HCl is the preferred acid, although

HNO3 is used to dissolve many metallic minerals

containing lead and silver.

`

Water is used before the acids to determinesolubility.

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` A centrifuge is a piece of equipment that

puts an object in rotation around a fixed

axis, applying a force perpendicular to the

axis.

` The centrifuge works using the sedimentation

principle, where centripetal acceleration is usedto evenly distribute substances (usually present

in a solution for small scale applications) of

greater and lesser density

` Lab centrifuge: no physical separation

between the solid and liquid phase butaccelerated settling due to centrifugal

acceleration.

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` Decantation is a process for separating some

mixtures by carefully pouring the solution from a

container so that the precipitate is left in the bottom

of the original container.` Usually some of the solution must be left in the

container, and care must be taken to prevent a

small amount of precipitate from flowing with the

solution out of the container. It's generally used to

separate a liquid from an insoluble solid.

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` The flame test is a

procedure used to detect

the presence of metal ions

by introducing a sample of

the element or compound

to a hot, non-luminous

flame, and observing the

color that results.

Samples are usually held on aplatinum wire cleaned repeatedly

with hydrochloric acid to remove

traces of previous analytes.

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Symbol Name Color As Arsenic Blue

B Boron Bright green

Ba Barium Pale/Apple green

Ca Calcium Brick red

Cs Cesium BlueCu(I) Copper(I) Blue

Cu(II) Copper(II) (non-halide) Green

Cu(II) Copper(II) (halide) Blue-green

Fe Iron Gold

In Indium Blue

K Potassium Lilac

Li Lithium Red

Mg Magnesium White

Flame test chart part 1

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Symbol Name Color

Mn(II) Manganese(II) Yellowish green

Mo Molybdenum Yellowish green

Na Sodium Intense yellow

P Phosphorus Pale bluish green

Pb Lead Blue

Rb Rubidium Red-violet

Sb Antimony Pale green

Se Selenium Azure blue

Sr Strontium Crimson

Te Tellurium Pale green

Tl Thallium Pure green

Zn Zinc Bluish green

Flame test chart part 2

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` To identify the cations present in a given liquid

sample

` To identify the cation and the anion in a given

sample of a salt` To write the name and correct formula of the salt

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` After solubility test, dissolve a pinch of sample in

the appropriate solution and use the resulting

solution as the cation test solution

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General Assaying Procedures

http://www.thegeozone.com/members/assay/assay04.jsp#solubility

Wikipedia, The Free Encyclopedia

http://en.wikipedia.org/wiki/Main_Page