Analysis

Front 1

How do you carry out a flame test?

Back 1

1. Dip a clean wire loop into a solid sample of the compound being tested

2. Put the loop into the edge of the blue flame from a Bunsen Burner

3. Observe and record the flame colour produced

Front 2

Lithium flame test colour

Back 2

Crimson

Front 3

Sodium flame test colour

Back 3

Yellow

Front 4

Potassium flame test colour

Back 4

Lilac

Front 5

Calcium flame test colour

Back 5

Orange-red

Front 6

Copper flame test colour

Back 6

Green

Front 7

Metal hydroxide precipitate tests

Back 7

Dilute sodium hydroxide solution is used in tests for some metal ions, which form metal hydroxides that are insoluble. This means that the metal hydroxides appear as precipitates.

Front 8

Aluminum precipitate test colour

Back 8

White

Front 9

Calcium precipitate test colour

Back 9

White

Front 10

Magnesium precipitate test colour

Back 10

White

Front 11

Copper precipitate test colour

Back 11

Blue

Front 12

Iron(II) precipitate test colour

Back 12

Green

Front 13

Iron(III) precipitate test colour

Back 13

Brown

Front 14

Distinguishing between aluminium, calcium and magnesium ions

Back 14

A few drops of dilute sodium hydroxide solution react to form a white precipitate with aluminium ions, calcium ions and magnesium ions. However, if excess sodium hydroxide solution is added:

the aluminium hydroxide precipitate dissolves to form a colourless solution

the calcium hydroxide precipitate is unchanged

the magnesium hydroxide solution is unchanged

This means that using sodium hydroxide can give a positive result for aluminium ions, but it cannot distinguish between calcium and magnesium ions.

Front 15

Testing for halide ions

Back 15

Silver ions react with halide ions to form insoluble precipitates

Front 16

Chloride test colour

Back 16

White

Front 17

Bromide test colour

Back 17

Cream

Front 18

Iodide test colour

Back 18

Yellow

Front 19

Test method

Back 19

To test for halide ions:

add a few drops of dilute nitric acid to the sample

add a few drop of dilute silver nitrate solution

Observe and record the colour of any precipitate that forms.

Front 20

Chromatography

Back 20

Paper chromatography is used to separate mixtures of soluble substances and to provide information on the possible identity of the substances present in the mixture

Front 21

Phases of chromatography

Back 21

Chromatography relies on two different 'phases':

the mobile phase is the solvent that moves through the paper, carrying different substances with it

the stationary phase is contained on the paper and does not move through it

The different dissolved substances in a mixture are attracted to the two phases in different proportions. This causes them to move at different rates through the paper.

Front 22

Rf value equation

Back 22

Rf=distance travelled by substance/distance travelled by solvent

Front 23

Hydrogen Test

Back 23

A burning splint is held at the open end of a test tube of the gas. Hydrogen burns rapidly with a squeaky pop

Front 24

Oxygen Test

Back 24

The test for oxygen uses a glowing splint inserted in the test tube of the gas. The splint re-lights in oxygen

Front 25

Carbon Dioxide Test

Back 25

The test for carbon dioxide uses an aqueous solution of calcium hydroxide (lime water). When carbon dioxide is shaken with or bubbled through limewater, the limewater turns milky (cloudy)

Front 26

Chlorine Test

Back 26

The test for chlorine uses litmus paper. When damp litmus paper is put into chlorine gas, the litmus paper is bleached and turns white.

Front 27

Precipitation Word Equation

Back 27

Aluminium Chloride + Sodium Hydroxide —> Aluminium Hydroxide + Sodium Chloride

Front 28

Carbonate Test

Back 28

Carbonate ions are detected using a dilute acid. Bubbles are given off when an acid is added to the test compound. The bubbles are caused by carbon dioxide. Limewater is used to confirm that the gas is carbon dioxide. It turns milky/cloudy when carbon dioxide is bubbled through it.

Front 29

Sulphate Test

Back 29

Add a few drops of dilute hydrochloric acid to the sample. Add a few drops of dilute barium chloride solution. A white precipitate forms if sulphate ions are present

Front 30

What is an instrumental method?

Back 30

A method that can identify elements and compounds. It is accurate, sensitive and rapid.

Front 31

Flame Emission Spectroscopy

Back 31

Used to analyse metal ions in solutions. The sample is put into a flame and the light given out is passed through a spectroscope. The output is a line spectrum that can be analysed to identify the metal ions in the solution and measure their concentrations.