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23 Cards in this Set
- Front
- Back
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Air
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a mixture of many different gases including water vapour. dry air is water when the water vapour as been removed |
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Nitrogen% Oxygen% Argon% Carbon Dioxide% |
78 21 1 0.04 |
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Atoms in a molecule are joined together by one or two more...
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Covalent bonds
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Covalent bonds
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Formed when atoms share a pair of electrons. A bond is a force holding atoms together. Forces arise because the positively charged nuclei of both atoms are attracted to the negatively charged shared pair of electrons. This force holds the atoms together strongly and rigidly. |
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Forces between molecules
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The attractive forces between small molecules are very weak. Very little energy is needed for molecules to overcome these forces and move apart, so simple molecular substances have low melting and boiling points. Molecules of elements and compounds have no electrical charge, so pure molecular substances cannot conduct electricity. |
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INTERMOLECULAR INTRAMOLECULAR |
BETWEEN - WEAK WITHIN - STRONG |
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An ionic bond
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a strong force of attraction between positively charged and negatively charged ions which holds them together in the crystal lattice. Ionic compounds have no overall charge as elements are balanced. |
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Coloured ions and precipitates
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A precipitate is the solid formed when two solutions mix CALCIUM - White COPPER - Light blue IRON (II) - Green Iron (III) Red-Brown ZINC - White |
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Testing for negative ions
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To test for a chemical for the presence of negative ions, first add an acid. If the chemical contains the carbonate ion it will bubble and fizz. This is called effervescence. Next, divide the solution, add silver nitrate to one part and a few drops of barium chloride/nitrare to the other part. Sulfate = white, iodide = yellow, bromide = cream, chloride = white, carbonate = effervesces |
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Minerals
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Make up the lithosphere
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Diamond
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A mineral made of crystalline forms of carbon made of giant covalent structures. They are very hard and require a lot of energy to break the bonds to allow atoms to move. High melting points Does not conduct electricity Carbon covalently bonded 4 times in a tetrahedral 3-D lattice |
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Graphite
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A mineral made of crystalline forms of carbon made of giant covalent structures. Carbon covalently bonded 3 times. Atoms arranged hexagonally in flat sheets. The sheets are strong but there is a weak force between the sheets so they slide over each other. Each carbon atom has one electron not bonded so electrons can move easily between layers, allowing graphite to conduct electricity. |
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Ores
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Rocks that contain minerals from which metals can be extracted
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Reduction Oxidisation |
Loss of oxygen Gain of oxygen |
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RAM - Bigger number Leads to RFM which is... |
the sum of the RAMs of all the atoms or ions shown in the formula.
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Calculating the mass of a metal
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= Total mass of (insert metal) atoms ---------------------------------------------------------- Gram formula mass of (insert metal compound) x 100% |
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Electrolysis
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Means passing an electric current through a liquid electrolyte, which is broken down into elements. Molten ionic compounds are electrolytes. |
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Electrolysis 2
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... is a way of obtaining reactive metals from their compounds. When molten ionic compounds are electrolysed the ions are attracted by, and move towards, the electrodes which carry the electric current into the electrolyte. |
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Electrolysis 3
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Positive ions move to the negative electrode - Cathode Negative ions move to the positive electrode - Anode Metals gain electrons at the cathode and become neutral metal atoms. At the anode, non-metal ions lose electrons and become neutral non-metal atoms. |
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Metals
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- high melting points - strength - malleable - electrical conductivity - let electricity through |
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Metallic Bond
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a force between metals that attracts the atoms together it is strong in most metals so atoms need a lot of energy to make them move out of their positions in the lattice. |
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Metallic bond 2
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metal atoms can lose their outer shells leaving positively charged ions. when metal atoms are packed together in a crystal the outer shell of electrons can move freely from one to another. They form a 'sea of electrons'. The positive ions are attracted to all the free electrons around them. This force keeps the ions in the lattice. |
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