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# A level chemistry

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

(4Al + 3O2--> 2Al2O3)
2. Work out the number of moles of aluminium oxide that can be formed first.
3. u do 54/molar mass of aluminium
then times the answer by 2/4
times this answer by the molar mass of aluminium oxide
4. (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 ???
5. no, dnt include the number in front. only do 54 ÷ 1 Aluminium
0.5 X 1 aluminium oxide
6. (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.
7. [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?
8. (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
9. (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?
10. (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.
11. For this, I got 102g for mass of AL2O3? Correct?
12. (Original post by coconut64)
For this, I got 102g for mass of AL2O3? Correct?
Sounds good.
13. (Original post by alow)
Sounds good.
cool
14. (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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