Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    2
    ReputationRep:
    I have an exam this Friday and I have no idea how to balance chemical equations. I've watched so many videos on it and even in class, my teacher only went over it once. Can someone help me out on balancing chemical equations? THNX
    Posted on the TSR App. Download from Apple or Google Play
    Offline

    4
    ReputationRep:
    The number of each atom needs to be the same on both sides of the equation. The ONLY thing you can do is change the coefficients of each species.

    That's really all there is to it.

    As an example:
    C4H10 + O2 -> CO2 + H2O

    As you can see, there is 4 C on the left but only 1 on the right. 10 H on the left but only 2 on the right. 2 O on the left but 3 on the right. Not balanced.

    First balance C
    C4H10 + O2 -> 4 CO2 + H2O

    Then H
    C4H10 + O2 -> 4 CO2 + 5 H2O

    Finally need to do O and it gets a bit tricky. We have 8 O in the 4 CO2 and 5 O in the 5 H2O. 8 + 5 = 13 so we need to get 13 O atoms on the left. Since it is O2 if we do 13/2 (or 6.5) O2 then it will balance.

    C4H10 + 13/2 O2 -> 4 CO2 + 5 H2O

    But we don't really like seeing that fraction, so instead if we multiply the entire equation by 2 it will get rid of it.

    2 C4H10 + 13 O2 -> 8 CO2 + 10 H2O
    Online

    9
    ReputationRep:
    I would only add that there is a golden rule, one I have come to realise isn't obvious to all students:

    Before you balance the sides of the equation you must make sure each formula you are using is the correct formula. Don't try to manipulate formulae for convenience - the formula is the formula regardless of how easy it makes balancing the equation.
    It sounds obvious, but I have come across so many students who try to change formulae to make the balancing easier.

    You may also want to have a look at my post here


    Good luck with your test.
 
 
 
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • Poll
    Did TEF Bronze Award affect your UCAS choices?
  • See more of what you like on The Student Room

    You can personalise what you see on TSR. Tell us a little about yourself to get started.

  • The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

    Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

    Quick reply
    Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.