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CHEMISTRY HELP URGENT A Level Watch

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    Hey guys I need help with oxidation numbers, if you could show how its done, it would be most appreciated.
    WO3 + 3H2 ----> W + 3H20
    Tungesten reaction with Hydrogen
    could you show whats being oxidised and reduced

    Also one more about sodium thiosulfate
    What is the oxidation number of sulphur in Na2 S2 O3 . 5H20 (Hydrated Sodium Thiosulfate)
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    Look at your past notes and stuff if you can and online resources.

    All elements on their own are 0. If they're not ions, then they balance to = 0. Since 03 = -6, tungsten is = +6. It goes to 0. This means it has gained 6 electrons because -6 add +6 = 0. Use OIL RIG (oxidation is loss [of electrons], Reduction is gain [of electrons]). We can conclude that Tungsten has been reduced since it gained 6 electrons.
    3H2 = 0 because it's on its own. When in the water molecule, it's now at +1 (two Hydrogens will balance the -2 of the oxygen). This means it's lost an electron. This means it's been oxidised.

    I'm not sure about sulfur but I think since:
    Na = +1 and there's 2 of them = +2
    O3 = -6
    +2 + -6 = -4.
    How do we make -4 = 0? Well sulphur must be +2 since there's two of them.
 
 
 
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