recations and elements

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what is a redox reaction?
Oxidation and reduction occurs simultaneously
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what is an oxidising agent?
accept electrons and get reduced
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what is a reducing agent?
donate electrons and get oxidised
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what do oxidation states do?
tell you the total number of electrons an element has donated or accepted
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what is the trend in boiling points of the halogens?
increase down the group due to increased van der Waals forces. Size and RAM of atoms increases.
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what is the trend in electronegativity of the halogens?
decreases down the group. Halogens are highly electronegative. As atoms are larger, electronegativity decreases.
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what is the colour and physical state of fluorine?
pale yellow gas
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what is the colour and physical state of chlorine?
green gas
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what is the colour and physical state of bromine?
red-brown liquid
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what is the colour and physical state of iodine?
grey solid
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what are the reactions of chlorine with water?
Cl2+H2O↔HCl+HClO, HClO+H2O↔ClO-+H3O+
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what does a halide ion do?
takes part in redox reaction, reduces something+ is oxidised itself. To reduce, halide ion loses an electron from its outer shell
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what can affect the reducing power of halides?
attraction between nucleus and outer electrons
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how do you test for halides?
Add nitric acid and silver nitrate. Fluorine-no ppt, chlorine-white ppt, bromine-cream ppt, iodine-yellow ppt.
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how do you test for halides?
add ammonia. Chloride ions-dissolve in dilute ammonia. Bromide ions-dissolve in conc ammonia. Iodide ions-insoluble in conc ammonia.
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what is the trend in atomic radius for group 2 elements?
decreases down group due to extra electron shells
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what is the trend in ionisation energy for group 2 elements?
decreases down group due to extra electron shells providing shielding. Reduces nucleus attraction to outer electrons.
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what is the trend in reactivity for group 2 elements?
increases down the group, the easier it is to lose electrons, the more reactive the element
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what is the trend in melting point for group 2 elements?
decreases down the group. Group 2 elements have metallic structures with their outer shell electrons being delocalised. Going down the group the ions get bigger
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what's the reaction of group 2 compounds with water?
M+2H2OM(OH)2+H2, Elements react more readily down the group due to the ionisation energies decreasing
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what are barium metals used for in medicine?
Barium sulphate used in meals to diagnose problems with the oesophagus, stomach or intestines. Patient swallows barium sulphate which coats the tissues so they show up on the X-rays.
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why can you only use barium sulphate in medicine?
other barium solutions are poisonous
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what is an ore?
natural substance a metal can be extracted from
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how do you extract aluminium?
Using electrolysis- ore is Al2O3 with various impurities. 1st impurities removed then dissolved in Na3AlF6 which lowers m.p. Cathode:Al3++3e-Al. Anode:2O2-O2+4e-.
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how do you extract titanium?
TiO2+2Cl2+2CTiCl4+2CO. TiCl4 purified by fractional distillation. Chloride reduced in furnace at 1000oc. TiCl4+4NaTi+4NaCl.TiCl4+2MgTi+2MgCl2
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what are the advantages of recycling metals?
Saves raw materials-ores finite resource. Saves energy-use less energy than metal extraction. Saves money to. Reduces waste sent to landfill. Reduces damage to landscape.
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what are the disadvantages of recycling metals?
Collecting and sorting metals from other waste can be difficult and expensive.Purity of recycled metal varies-usually other metals and impurities mixed in. Recycling may not produce consistent supply to meet demand.
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Other cards in this set

Card 2

Front

what is an oxidising agent?

Back

accept electrons and get reduced

Card 3

Front

what is a reducing agent?

Back

Preview of the front of card 3

Card 4

Front

what do oxidation states do?

Back

Preview of the front of card 4

Card 5

Front

what is the trend in boiling points of the halogens?

Back

Preview of the front of card 5
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