GCSE chemistry help!! advanced balancing equations

Chemistry discussion, revision, exam and homework help.

Announcements Posted on
IMPORTANT: You must wait until midnight (morning exams)/4.30AM (afternoon exams) to discuss Edexcel exams and until 1pm/6pm the following day for STEP and IB exams. Please read before posting, including for rules for practical and oral exams. 28-04-2013
Sign in to Reply
  1. lgellhorn's Avatar
    • New Member
    • Posts: 5
    GCSE chemistry help!! advanced balancing equations
    If we are given H2SO4 + Al = ? + H2
    How do we know that the answer will be balanced out to be
    3H2SO4 + 2Al = Al2(SO4)3 +3H2

    i just dont get how Al2(SO4)3 is bonded ? ionically ?? covallently ? please i need answers
  2. CW12345's Avatar
    • Junior Member
    • Posts: 45
    Re: GCSE chemistry help!! advanced balancing equations
    I think it's ionically bonded, Al has a 3+ charge, SO4 has a 2- charge, we need the charge to add up to 0, so 2 Al gives 2x3=6 and 3SO4 gives 3x-2=-6, giving an overall charge of 0. Now that we have Al2(SO4)3, we know we have (SO4)3 on the right hand side, so we need 3 SO4 on the left, so we get 3H2SO4 on the left, similarly it's Al2 on the right, so we need 2Al on the left. Finally we have 3H2SO4 on the left, so we need 3H2 on the right.
  3. ChemicalBond's Avatar
    • Adored and Respected Member
    • Location: Dover
    • Posts: 494
    Re: GCSE chemistry help!! advanced balancing equations
    Hey there! Aluminium Sulphate is an ionic compound. The charge on an Aluminium ion is +3, and the Sulphate ion is S042-. You have to make sure that each component's total charge adds to 0. Therefore, the negative ion needs to have an overall of -6 and the positive as +6 as they cancel out.

    Al+3 - you need 2 of these
    SO42-- you need 3 of these.

    Al2(SO4)3
  4. nv13's Avatar
    • New Member
    • Posts: 20
    Re: GCSE chemistry help!! advanced balancing equations
    Al3+ will ionically bonded to the complicated/compound ion SO42-, which is an ion formed from covalently bonded atoms. This is what then forms Al2(SO4)3
    Last edited by nv13; 10-06-2012 at 21:46.
Sign in to Reply
Share this discussion:  
Article updates
Moderators

We have a brilliant team of more than 60 volunteers looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

Reputation gems:
The Reputation gems seen here indicate how well reputed the user is, red gem indicate negative reputation and green indicates a good rep.
Post rating score:
These scores show if a post has been positively or negatively rated by our members.