Chemistry+balancing equation tips

We are on combustion reaction at the moment in chemistry, and I have to say, these reactions are like extremely hard to balance(well, just alot of erasing). It takes me a while to balance combustion reactions and I want to know if theres any tips in balancing them? Should I balance a certain element first to make it easier?

asked by Chopsticks
  1. Look at the products first to determine how much of the reactants you need.
    I balance oxygen last because you can add (usually) exactly what you need as a single element on the left. Then if it comes out something and a half, multiply by 2.

    posted by DrBob222
  2. Today, we balanced combustion reactions and I got numbers up to 62! Big numbers are intimidating to me :P. is it always going to be like that for combustion reactions?

    posted by Chopsticks
  3. Most combustion reactions are small numbers.
    C4H9 + O2 --> CO2 + H2O
    I see the H9 on the left and H2 on the right and I know I have a problem right off the bat because there is no whole number I can multiply by to get from 2 to 9. So right off the bat I multiply C4H9 by 2
    2C4H9 + O2 ==> CO2 + H2O
    Now with 18 H on the left I can balance H on the right.
    2C4H9 + O2 ==> CO2 + 9H2O
    Now I can balance C.
    2C4H9 + O2 ==>8CO2 + 9H2O
    Now I count the O I have on the right. That's 16 from CO2 and 9 from H2O which makes 25, another odd number. Usually, what I do is say, ok, I need 25/2 O2 like this,
    2C4H9 + (25/2)O2 ==> 8CO2 + 9H2O
    Then I multiply everything through by 2 to get rid of the half so that 25/2 becomes 25.
    4C4H9 + 25 O2 ==>16CO2 + 18H2O
    Then I check it. ALWAYS check it.
    16 C left and right.
    36 H left and right.
    50 O left and 50(32 from CO2 + 18 from H2O = 32+18 = 50).
    One thing about balancing equations is that you can ALWAYS know if you are right by checking the equation when you are finished. I always check mine to make sure everything balances.

    posted by DrBob222
  4. Ah, another problem I find that I have is that sometimes, I use double the number im suppose to use, and even those they balance, its 2x what I need. Is there a way to check that? it doesnt happen often, but it does.

    posted by Chopsticks
  5. Sometimes that happens to me, too. I just end up dividing everything by two and don't worry about it.

    posted by DrBob222
  6. H20

    posted by H + O2

Respond to this Question

First Name

Your Response

Similar Questions

  1. Chem

    The entropy of combustion of benzoic acid is zero. This means that... a)combustion is not spontaneous here. b)combustion is spontaneous, however, since the reaction is exothermic. c)combustion is spontaneous, however, since the

    A 8.90-g sample of ethane, C2H6, is mixed with 18.8 atm of O2 (an excess) in a 1.50 L combustion chamber at 130.0°C. The combustion reaction to CO2 and H2O is initiated and the vessel is cooled back to 130.0°C. What is the final
  3. Chemistry

    The combustion of methanol (CH3OH) forms carbon dioxide and water vapor. A combustion reaction refers to a reaction of a substance with oxygen gas. What is the balanced equation?
  4. chemistry

    Do any of you think that spontaneous combustion is possible? If a reaction brings about an increase of entropy (increase in randomness) and also exodermic, then a reaction is spontaneous. Right? Yes, I think spontaneous combustion
  5. Chemistry

    In a reaction in which A + B yields AB, the reaction is referred to as a _________. A. decomposition reaction B. double-replacement reaction C. combustion reaction D. composition reaction
  6. Chemistry...HELP!!!!

    In a reaction in which A + B yields AB, the reaction is referred to as a _________. A. decomposition reaction B. double-replacement reaction C. combustion reaction D. composition reaction i think is a
  7. Chemistry

    Hydrogen and methanol (CH3OH) have both been proposed as alternatives to hydrocarbon fuels. a) Write balanced chemical equations for the complete combustion of hydrogen and the complete combustion of gaseous methanol. Combustion
  8. chemistry

    Methane (CH4) is the main component of natural gas. It is burned for fuel in a combustion reaction. The unbalanced combustion reaction for methane is shown below. CH4 + O2 CO2 + H2O + heat When the reaction is balanced, how many
  9. chemistry

    During the combustion of 5.00g of octane C8H18, 239.5 kcal is released. Write a balanced equation for the combustion reaction. Are reactants or products favored? What is the sign of change of heat for this reaction? how much
  10. chemistry

    Examine the unbalanced equation. CH4 + O2 → CO2 + H2O What is the best classification for the unbalanced equation's reaction, and why? It is a combustion reaction because carbon dioxide (CO2) is emitted as a product. It is a

More Similar Questions