Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
31 Cards in this Set
- Front
- Back
How do you carry out a flame test? |
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 |
|
Lithium flame test colour |
Crimson |
|
Sodium flame test colour |
Yellow |
|
Potassium flame test colour |
Lilac |
|
Calcium flame test colour |
Orange-red |
|
Copper flame test colour |
Green |
|
Metal hydroxide precipitate tests |
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. |
|
Aluminum precipitate test colour |
White |
|
Calcium precipitate test colour |
White |
|
Magnesium precipitate test colour |
White |
|
Copper precipitate test colour |
Blue |
|
Iron(II) precipitate test colour |
Green |
|
Iron(III) precipitate test colour |
Brown |
|
Distinguishing between aluminium, calcium and magnesium ions |
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. |
|
Testing for halide ions |
Silver ions react with halide ions to form insoluble precipitates |
|
Chloride test colour |
White |
|
Bromide test colour |
Cream |
|
Iodide test colour |
Yellow |
|
Test method |
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. |
|
Chromatography |
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 |
|
Phases of chromatography |
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. |
|
Rf value equation |
Rf=distance travelled by substance/distance travelled by solvent |
|
Hydrogen Test |
A burning splint is held at the open end of a test tube of the gas. Hydrogen burns rapidly with a squeaky pop |
|
Oxygen Test |
The test for oxygen uses a glowing splint inserted in the test tube of the gas. The splint re-lights in oxygen |
|
Carbon Dioxide Test |
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) |
|
Chlorine Test |
The test for chlorine uses litmus paper. When damp litmus paper is put into chlorine gas, the litmus paper is bleached and turns white. |
|
Precipitation Word Equation |
Aluminium Chloride + Sodium Hydroxide —> Aluminium Hydroxide + Sodium Chloride |
|
Carbonate Test |
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. |
|
Sulphate Test |
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 |
|
What is an instrumental method? |
A method that can identify elements and compounds. It is accurate, sensitive and rapid. |
|
Flame Emission Spectroscopy |
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. |