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Homework Help: Balancing equation - What is the chemical formula of cement?

  1. Sep 19, 2009 #1
    There are 2 parts to this question:

    1. If limestone (calcium carbonate) and clay (assume aluminum silicate) are mixed together and heated then the result is cement. Cement is a mixture of calcium oxide, carbon dioxide, aluminum oxide, and calcium silicate. These bags can be purchased at any building supplies store. Write a balanced equation.
    2. If the factory has 100.0 kg of clay in its reaction vessel, then how much limestone will they need to exactly react with the clay to produce the cement?

    Ok, so the first part is relatively simple, the only problem is I can not find what the chemical formula of cement is... there appear to be quite a few different formulas online. limestone is (CaCO3) and clay or aluminum silicate is (Al2SiO5). Once I find what cement is it will be easy to solve.

    I'm a little uncertain about the next part too.... ok, so I found out there are 162.05g/mol of Aluminum silicate, which would make 162,050mols of clay in the reaction vessel. So where can I go from here? thanks in advance people
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Sep 19, 2009 #2
    Not sure if it's correct, but in your post it's stated that cement is a mixture.
  4. Sep 19, 2009 #3


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    Staff: Mentor

    I will be brutally honest - this is a stupid question. Cement is a mixture of not precisely known composition, as different compositions are required for different applications. There are many reactions taking place and it is not possible to write ONE balanced reaction.

    That said, some googling will lead you here:


    and you will find some of the most important reactions taking part during cement hardening there.
    Last edited by a moderator: Aug 13, 2013
  5. Sep 20, 2009 #4
    its a stupid question I know, why didn't my teacher just give me what they think the chemical formula for cement is? I think this question is a dead end
    Last edited by a moderator: Aug 13, 2013
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