balancing equations

[metal_dragon35]

hay im balancing chemical equations in science and i sort of get but id like to know if some one out there can explain it a little better than my teacher i have a test coming up the following week its finals ](*,) and i need to pass so will someone plaese help me if you would i would realy be thankful

[scourge]

I’m not a chemist, but I know this much—both sides of the equation always have the same number of each kind of atom, just combined differently. As in 2H2 + O2 = 2H2O.

[edit: if Martin can do it so can I ]

[martin]

I’m not a chemist, but I know this much—both sides of the equation always have the same number of each kind of atom, just combined differently. As in H2 + O2 = O + H2O.

But O is not molecule occurring easily or naturally. A better equation is

2 H2 + O2 = 2 H2O

Martin

[Edited to fix error]

[dgruss23]

hay im balancing chemical equations in science and i sort of get but id like to know if some one out there can explain it a little better than my teacher i have a test coming up the following week its finals ](*,) and i need to pass so will someone plaese help me if you would i would realy be thankful

Chemistry is a subject that you understand by doing example problem after example problem until you get it. My recommendation is that you get together with someone else in your class that understands the concept and have them explain it to you. But you need to keep working on problems - try again examples you've already done.

I can explain a few examples to you, but I don't know if you're talking about the basic equations or some of the difficult redox reactions. I'd also be concerned that if you're having trouble with balancing, there are probably many other concepts you're having a hard time with. Its hard to do stoichiometry for example, if you can't balance equations.

[dgruss23]

I’m not a chemist, but I know this much—both sides of the equation always have the same number of each kind of atom, just combined differently. As in H2 + O2 = O + H2O.

But O is not molecule occurring easily or naturally. A better equation is

2 H2 + O2 = 2 H2O

Martin

[Edited to fix error]

Really, you'd just want to write:

2H2 + O2 = 2H2O

O2 is not a product of the reaction. If any is left after the reaction it is considered "excess".

[Russ]

I would think it would have to be 2 H2 + O2 = 2 H2O or if you have just H2 + O2 = H2O + O. But having a single oxygen atom is unlikely so it would have to attach to some other available site.

[pghnative]

Does anyone know the reaction mechanism for burning hydrogen to form water? It seems to me that you might first form hydrogen peroxide:

H-H + O-O --- HOOH

followed by:

HOOH + H-H --- HOH + HOH (that is, 2H2O, of course)

[metal_dragon35]

thank you dg russ i apretate the help your rite it is something that has to be aced by doing exp after axp o and im doing bacic equations like
hydrogen +oxigen (well sence oxigen and hydrgen are diatomic and cant be fount a lone they end up beeing h2+o2 ) so it has to be
2 h2 +o2 +2 h2o corect am i rite another is (tell me if im ite on this one im working it out but i dont know if imm doing it rite)
__KMnO4=___K2O+__MnO+__O2(thats the problem)now i solve pleaz corect me if im wrong.
4KMnO4=2K2O+4MnO+5O2

tell me if im wrong but i worked that out i hope im rite but if im not correct me and explain wat i did wrong thank you.

[Peter B]

thank you dg russ i apretate the help your rite it is something that has to be aced by doing exp after axp o and im doing bacic equations like
hydrogen +oxigen (well sence oxigen and hydrgen are diatomic and cant be fount a lone they end up beeing h2+o2 ) so it has to be
2 h2 +o2 +2 h2o corect am i rite another is (tell me if im ite on this one im working it out but i dont know if imm doing it rite)
__KMnO4=___K2O+__MnO+__O2(thats the problem)now i solve pleaz corect me if im wrong.
4KMnO4=2K2O+4MnO+5O2

tell me if im wrong but i worked that out i hope im rite but if im not correct me and explain wat i did wrong thank you.

G'day Metal_Dragon35

Yes, the example you've given at the bottom is correct.

The way I worked it out was to list the atoms down the page, in this case:

K
Mn
O

We know that there are 4 O atoms for every K atom and Mn atom, we also know that the ratio must be the same before and after, and we also know that we need whole numbers of atoms (no fractions here).

If you look at the right hand side of the equation, you see that one product is K20, which means you end up with at least two K atoms. This means you must start with at least two K atoms. That in turn would require you to start with at least 2 molecules of KMnO4.

But if you start with only 2 molecules of KMnO4, you'll end up with 2.5 molecules of O2, which won't work. So if you double everything, you start with 4 molecules of KMnO4, and end up with the results you specified.

[metal_dragon35]

thank you peter that helps now if some one can post an ex(with out the anser) and let me try to solve it maby i will do good on this test tomorow pleaz some one help i need to pass this test.and once agin peter thank you

[Peter B]

thank you peter that helps now if some one can post an ex(with out the anser) and let me try to solve it maby i will do good on this test tomorow pleaz some one help i need to pass this test.and once agin peter thank you

No worries, Metal_Dragon35.

Here's an example for you to try out:

H2SO4 + NaOH -> Na2SO4 + H2O

(That is, sulphuric acid plus sodium hydroxide goes to sodium sulphate and water.)

(How do you do subscripts?)

[frogesque]

And for afters you could try the combustion of methane

CH4 + O2 => CO2 + H2O

Peter B It's messy to do and approximate but I just changed font size for the subscripts.

[dgruss23]

tell me if im wrong but i worked that out i hope im rite but if im not correct me and explain wat i did wrong thank you.

It looks like others have helped you. I'd say what you've done wrong is wait until the last minute to learn this stuff. Balancing equations is a very small part of a general chemistry class. I'm assuming you're going to see a lot more on your final than this.

Good luck on your test, but if it doesn't go well, make sure to get right on this stuff from the beginning if you take it again!

[metal_dragon35]

thanks guys for your help with the balencing thing i got a b on the test it was easy i understand more on how to balence now much better thank you agin