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Homework Help: Need your help with organic chemistry problems please!

  1. Feb 24, 2013 #1
    1. The problem statement, all variables and given/known data

    From burning 7,2 litres of an alkyne, we get 26,4 grams of carbon dyoxide CO2 and 5,4 grams of H2O. Determine the formula of the alkyne.

    2. Relevant equations


    3. The attempt at a solution
    x litres of Alkyne→n x 44grams of CO2
    7,2 litres→26,4

    But, what do I do with the water?? How do I find the "n"?

    1. The problem statement, all variables and given/known data
    700grams of CaC2 react with water H2O and give 120litres of C2H2. Find the mass in grams of benzene C6H6?

    2. Relevant equations

    3. The attempt at a solution

    I understand that a molecule of benzene is produced by polymerizing 3 molecules of ethyne (C2H2), but how in the world do I use the given info, when I know both the amount of CaC2 that reacts with water and the volume of C2H2 that I get from the reaction? What do I need to estimate??

    1. The problem statement, all variables and given/known data
    A mixture of ethane+ethene+ethyne is burned in the presence of O2 from air.

    a) How many litres of Oxygen is needed for burning 10 litres of the mixture?

    b) In how many litres of air is found this amount of oxygen?

    2. Relevant equations

    3. The attempt at a solution
    This is the difficult part, I am not sure whether I have done the equation above correctly or not?? Do I need to take each compound (ethane, ethene and ethyne) and do their burning reactions separately? What do I do from there?

    Thank you.
  2. jcsd
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