>.< Flashcards
Colour of Litmus in an acidic solution
Red
Colour of Litmus in a basic solution
Blue
Colour of Universal Indicator [Increasing pH]
Red — Purple
pH Colour Range of Phenolphthalein
Colourless - Pink; Colour Change [8.3 - 10]
pH Colour Range of Methyl Orange
Red - Yellow; colour change [3.1 - 4.4]
pH Colour Range of Bromothymol Blue
Yellow - (Green) - Blue; colour change [6.0 - 7.6]
Describe the detoxification process of the cycad
The seeds of the cycad are toxic and carcinogenic, thus:
Anaerobic Fermentation and Leaching:
Fermentation involves soaking and burning the plant to fully ripen.
Leaching involves placing the cycad seeds in dilly bags and dissolve the water-soluble toxins under running water. Still water is not used as the toxins are not fully soluble
Describe a natural buffer system
Seawater has a buffer system involving carbonic acid and hydrogen carbonate.
Describe the Indigenous treatment of acids and bases
Clay and ochre were dried and crushed before adding water to form a paste, applied to the skin or ingested.
Clay is a detoxifying agent that neutralises excess acid in the stomach, relieving stomach pains
Aluminium
Chemical Makeup of Complex Ions
Transitional Metal + Ligand Molecule/Ion
Common Examples of Ligands
Water, Ammonia, Chloride, Hydroxide
Purpose of the Ligand in a Complex Ion
Ligands act as an electron donor
Formal Term for the bond between the transitional metal and the ligand
Coordinate covalent bond
Recall the general solubility rules
SNAAP + Group 1 metals:
Sodium
Nitrate
Ammonium
Acetate
Potassium
Exception: Lithium Phosphate
Neutralisation in Industry
Sodium Carbonate is used to neutralise acid spills and acidic wastage to minimise environmental damage; weak bases are used as exothermic.
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Limitations of pH indicators
Limitations:
- The substance must be in solution or gaseous; can only measure moisture
- Destroys sample
- Slightly acidic
- Qualitative not quantitative
- Solution must be colourless/ transparent or translucent or will distort results
- Affected by temperature
Environmental monitoring
Quality of
- Air
- Soil
- Water
Heavy Metals + Trace Elements
Flame Colour of Barium Ion
Pale Green
Flame Colour of Calcium Ion
Orange-Red
Flame Colour of Magnesium Ion
No Colour
Precipitation Test for Barium Ion
Addition of sulfate ion produces a white precipitate
Precipitation Test for Calcium Ion
Addition of sulfate ion produces a white precipitate
Flame Colour of Lead Ion
Trick Question; Poisonous as a vapour
Precipitation Test for Silver Ion
Addition of chloride ion produces a white precipitate
Addition of bromide ion produces a cream precipitate
Addition of an iodide ion produces a yellow precipitate
Precipitation Test for Copper Ion
Addition of a strong base produces a blue precipitate
Flame Colour of Copper Ion
Blue-Green
Precipitation Test for Iron (II) Ion
Addition of a strong base produces a green precipitate
Precipitation Test for Iron (III) Ion
Addition of a strong base produces a brown precipitate
Sequence for testing cations
Chloride ions, sulfate ions, hydroxide/base
Precipitation Test for Chloride Ion
Addition of silver ion produces a white precipitate; decomposes in sunlight
Precipitation Test for Bromide Ion
Addition of silver ion produce a cream precipitate
Precipitation Test for Iodide Ion
Addition of silver ion produces a yellow precipitate
Precipitation Test for Hydroxide Ion
Addition of copper ion produces a blue precipitate
Addition of iron (II) ion produces a green precipitate
Addition of iron (III) ion produces a brown precipitate
Litmus - Blue
Test for Acetate Ion
Litmus - Red
Test for Carbonate Ion
Nitric acid; bubbling [limewater test]
Precipitation Test for Sulfate Ion
In acidic solution, white precipitation with barium
Precipitation Test for Phosphate Ion
In basic solution, white precipitation with barium
Sequence for testing anions
Nitric acid, barium, ammonium + barium, silver
