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    What mass of aluminium oxide can be made by burning 54g of aluminium?

    (4Al + 3O2--> 2Al2O3)
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    Work out the number of moles of aluminium oxide that can be formed first.
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    u do 54/molar mass of aluminium
    then times the answer by 2/4
    times this answer by the molar mass of aluminium oxide
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    (Original post by baz1998)
    u do 54/molar mass of aluminium
    then times the answer by 2/4
    times this answer by the molar mass of aluminium oxide
    so 54/108= 0.5
    0.5*(2/4)= 0.25
    0.25*204=102g ???
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    no, dnt include the number in front. only do 54 ÷ 1 Aluminium
    0.5 X 1 aluminium oxide
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    (Original post by grace_wh)
    so 54/108= 0.5
    0.5*(2/4)= 0.25
    0.25*204=102g ???
    108 isn't the relative atomic mass of aluminium.
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    [QUOTE=grace_wh;67518646]What mass of aluminium oxide can be made by burning 54g of aluminium?

    i did the following, not 100% sure though

    54/(4x26)
    ans/2
    ans x Mr od Al2O3

    to get an answer of 25.96g?
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    (Original post by Jassy16)
    What mass of aluminium oxide can be made by burning 54g of aluminium?

    i did the following, not 100% sure though

    54/(4x26)
    ans/2
    ans x Mr od Al2O3

    to get an answer of 25.96g?
    That's wrong.

    Also try not to post full answers, it won't help the OP learn. Read this: http://www.thestudentroom.co.uk/show...9#post64637319
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    (Original post by alow)
    That's wrong.

    Also try not to post full answers, it won't help the OP learn. Read this: http://www.thestudentroom.co.uk/show...9#post64637319
    where did i go wrong?
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    (Original post by Jassy16)
    where did i go wrong?
    You don't multiply the atomic mass by the stochiometric coefficient, and the atomic mass of aluminium is not 26.
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    For this, I got 102g for mass of AL2O3? Correct?
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    (Original post by coconut64)
    For this, I got 102g for mass of AL2O3? Correct?
    Sounds good.
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    (Original post by alow)
    Sounds good.
    cool
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    (Original post by grace_wh)
    What mass of aluminium oxide can be made by burning 54g of aluminium?

    (4Al + 3O2--> 2Al2O3)
    First of all, find the moles of aluminium i.e moles of aluminium=mass of aluminium burnt(54)/ molar mass of aluminium (27) then using your balanced equation, compare the moles of Aluminium: Aluminium Oxide which is 4:2. You'll get your moles of Aluminium Oxide and then, you can get the mass of aluminium oxide. (Again, use the formula, mass=moles into molar mass of aluminium oxide)
 
 
 
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