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    • Thread Starter
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    Hi all,

    I am doing a SKE in chemistry and stuck with something...

    The question is: Zinc reacts with phosphoric acid to form zinc phosphate and hydrogen gas.

    Reaction uses 13.08 g of zinc in 0.500 dm3 of phosphoric acid solution...

    So what I have done is

    relative mass of zinc is 65.4
    13.08 g of zinc

    65.4/13.08 = 0.2 moles of zinc

    0.2 / 0.500 dm3 = 0.4 mol dm-3

    How do you work out volume of hydrogen given off?

    Equation is: 3Zn + 2H3PO4 = ZN3(PO4)2 + 3H2

    Thanks
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    (Original post by Lambert87)
    Hi all,

    I am doing a SKE in chemistry and stuck with something...

    The question is: Zinc reacts with phosphoric acid to form zinc phosphate and hydrogen gas.

    Reaction uses 13.08 g of zinc in 0.500 dm3 of phosphoric acid solution...

    So what I have done is

    relative mass of zinc is 65.4
    13.08 g of zinc

    65.4/13.08 = 0.2 moles of zinc

    0.2 / 0.500 dm3 = 0.4 mol dm-3

    How do you work out volume of hydrogen given off?

    Equation is: 3Zn + 2H3PO4 = ZN3(PO4)2 + 3H2

    Thanks
    At room temperature 1 mole of gas occupies about 24 litres
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    you know 1 mole of any gas at standard temperature and pressure has a volume 24 litres. So what volume does 0.2 moles of hydrogen have?
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    Thanks both.

    So is it 0.4 if Hydrogen is diatomic?


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    One mole of Zn produces one mole of H2.
 
 
 
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