C16: Important things to Remember Flashcards
Steps in extraction of Aluminium from its ore
- Aluminium es extracted by electrolysis 2. Alumina (Al203) is obtained from bauxite 3. Aluminuim oxide is molten in the presence of cryolite 4. The electrolyte is molten aluminium oxide and contains the aluminium and oxide ions 5. Graphite electrodes are used 6. Aluminium ion reduced to aluminium metal at the cathode which is molten and is tapped off. 7. Oxide ion is oxidized to Oxygen gas at the anode.
Steps in the extraction of Iron
- The Iron ore is hematite and magnetite. 2. CO is the reducing agent. 3. Iron ore, Coke, and limestone poured in at the top of the furnace. 4. Hot air blown in at the bottom 5. Hot air reacts with coke(carbon) to form carbon dioxide and the carbon monoxide 6. carbon monoxide reduces the iron ore to iron, which is molten. This is tapped off. 7. Limestone used to remove the main impurity, silicon dioxide in the form of calcium silicate.
Extraction of sucrose from sugar cane
Sugar cane ——–> Crusher ——–> Clarification ——–> Filtration ———> Evaporation ———> Vacuum Crystallization —–> Centrifugation Steps: 1. Sugar cane cut up by shredding machine into small chips 2. The chips are then crushed and rolled under spray of hot water, expelling the cane juice (sucrose) which is acidic and dilute. 3. Cane fibre (bagasse) is removed and used for electricity. 4. Calcium hydroxide is added to the cane juice to neutralize it and settle out the impurities. This process is called clarification. 5. Filtration of the clarified cane juice to remove solid impurities 6. Evaporation: The cane juice in made more concentrated by boiling off water 7. Vacuum crystallization - syrup is concentrated to the point of saturation to form sugar crystals mixed in a thick syrup called molasses. 8. Centrifugation: sugar crystals separated from the molasses. and dried.
Steps in producing ethanol from sucrose (FERMENTATION)
Fermentation: Process by which microorganisms such as bacteria and fungi break down sugars in the absence of oxygen to form an alcohol and carbon dioxide Steps to produce ethanol (rum) from molasses 1. Molasses is diluted with water 2. Yeast is placed in the dilute molasses and left to ferment for for 48hrs. This produces about 15% ethanol. 3. The ethanol and water mixture is distilled to obtain more concentrated ethanol.
Define isotopy
The existence of atoms of a single element that have the same atomic numbers but different number of neutrons
What is are isotopes?
Different atoms of the same element with the same atomic number but different number of neutrons
What is a radioactive isotope?
An isotope of an element that has an unstable nucleus that will spontaneously undergo radioactive decay to emit small particles of radiation
What are the uses of radioactive isotopes?
1.Carbon-14 dating 2.Cancer treatment(radiotherapy) 3.Generation of electricity in nuclear plants 4.Heart pacemakers Tracers
Define relative atomic mass?
Relative molecular mass is the average mass of a molecule compared to one-twelfth the mass of a carbon-12 atom
what is the use of a separating funnel
To separate immiscible liquids that have different densities or to separate 2 solutes dissolved in the same solvent.
How to separate KI from iodine when both are dissolved in water?
- Pour the mixture in a separating funnel. 2. Add a solvent such as hexane that will dissolve the iodine, but does not mix with water. 3.The hexane will dissolve the iodine and the water will dissolve the potassium iodide salt. And now the 2 a separated 4. Now use the separating funnel to drain off the more dense mixture, in this case the solution of potassium iodide.
what is an acid?
a substance containing hydrogen that can be replaced by a metal to for a salt
What is an acid salt?
A salt that is formed when the H+ ions in an acid are only partially replaced by metal or ammonium ions
What is the Basicity of an acid?
The number of protons produced per molecule of acid when dissolved in water
What are acid anhydrides
compound that reacts with water to form an acid
name 4 examples of acid anydrides
- carbon dioxide
- sulphur dioxide
- sulphur trioxide
- nitrogen dioxide
what is a base?
a proton acceptor
what is an alkali
a soluble base that dissolves in water to form a solution that contains OH- ions
Name 4 indicators
- litmus
- phenolpthalein
- methyl orange
- screened methyl orange
definition of a weak base
partially ionises when dissolved in water
the 4 main groups of oxides are:
- acidic oxides
- basic oxides
- amphoteric oxides
- neutral oxides
basic oxides are oxides of _________
metals
Neutral oxides are oxides of some (1)____________ which do not react with (2)_____________ or (3)_________. examples of neutral oxides are(4)_______________
- non-metals
- acids
- alkalis
- CO, NO, N2O
definition of a salt
substance formed when some or all of the H+ ions in an acid have been replaced by metal or ammonium ions
