16 replies to this topic

[bogboogalars]

Ok I recently got a worksheet with around 50 chemical equations I need to balance, aaand a few have been kicking my butt, well anyway, if someone could and/or would help that would be great.
Equations...

Al2(SO4)3+Ca(OH)2 ----> Al (OH)3+CaSO4

FeCl3+NH4 OH--->Fe(OH)3+NH4Cl

and again thanks.

Edited by bogboogalars, 06 May 2008 - 09:10 PM.

[Foam Total War]

Ok I recently got a worksheet with around 50 chemical equations I need to balance, aaand a few have been kicking my butt, well anyway, if someone could and/or would help that would be great.
Equations...

Al2(SO4)3+Ca(OH)2 ----> Al (OH)3+CaSO4

FeCl3+NH4 OH--->Fe(OH)3+NH4Cl

and again thanks.

You're right, those are quite tricky. Sorry I can't help, plus Chemical was last semester so it's not fresh for me. One more thing, when the number's after an element it's in subscript which means that only that element has the number of it denoted by the subscript, right? Sorry if that sounded confusing but I couldn't figure out how to word it. Good luck anyway.

Edited by Foam: Total War, 06 May 2008 - 09:26 PM.

[bogboogalars]

I believe the subscript is the the number of electrons but i'm not sure...

[Captain]

It's funny, because that's what I'm doing in school too! I probably should have done that homework, but it's too late now. I'm going to bed.

[aetherguy881]

Please tell me this is a joke. Honestly, what are some of the other equations you have there? I solved these in less than 2 minutes. It's all simple addition and subtraction. Sorry to be a hard ass, but these are a walk in the park.

However because I'm a nice guy (usually?) I solved 'em for you.

The first one (rating: easy)

Al2(SO4)3+Ca(OH)2 ----> Al (OH)3+CaSO4

ans

Al2(SO4)3+3Ca(OH)2 ----> 2Al (OH)3+3CaSO4

The second one (rating: easier)

FeCl3+3NH4OH ---> Fe(OH)3+3NH4Cl

Now to help you since you thought they were confusing. Take for example the NH4, this is one molecule, thus any coefficients before it multiply the whole thing. Think of the whole molecule as a whole, not parts, that comes later . so in essence, the second product in the second problem could look like this and still be (mathematically) correct:

3((NH4)(Cl)) such that there's 3NH4 and 3Cl

It also helps to do a check once you've finished balancing it.

For example, the second one again. I use a little chart, it helps a lot.

reactant/product - reactant side|product side
Fe - 1|1
Cl - 3|3
NH4 - 3|3
OH - 3|3

That way you can see if you have made an error.

Now don't ask if I'm good in chem, I just know what I'm doing in some areas of chemistry, I'm an EE major, I've only had chem in high school and once here. In this basic chem, there's nothing to it.

Hope I helped enough and that you have a greater (even marginal) understanding of balancing chemical equations.

[bogboogalars]

Thank you that helped a lot I was trying to see if I was doing it right, It prooved one thing to me... I'm screwed...

Edited by bogboogalars, 06 May 2008 - 09:58 PM.

[aetherguy881]

Why do you say you're screwed?

Did you really goof off that much in class?

When will people learn, take education seriously. It'll help in the long run. That and don't let your guidance counselor sign you up for classes that you don't need... (In highschool)

I'm not saying that to you, just in general...

[bogboogalars]

Nah I don't goof off much I just was absent the day we learned this stuff (like yesterday), and now I have to do this stuff without knowing how to do it...O well such is life.

[aetherguy881]

This problem is easily solved, stay after school with the teacher and learn it. Trust me, it helps, then while there, try some of the homework yourself and have her check it for you. Don't ask for answers, just try to understand it.

Teachers are called teachers for a reason. Or can you not stay after due to work or something? School is generally more important than a high school job.

Edited by aetherguy881, 06 May 2008 - 10:03 PM.

[Lynx]

Hey, booboo, i recently got a 97/105 on a Balancing equations test so you can pm me if you can't pm him for help.

Also, PLEASE fix you spelling and grammar. You are a new member and writing poorly isn't going to let you stay here long.

Not saying I'm a vet or something, it is that I've been here longer than you.

Just for kicks, lets see if you can get Hydroxic acid --> ____ It's decomposition, and a funny one too.

Edited by Lynx, 06 May 2008 - 10:27 PM.

[Omega]

Dangit, y'all beat me to it.

And you only did equation balancing yesterday? I did that in like October. I'm 14 now, I was 13 at the time.

Yeah, for the second one (quite easy) I got:

FeCl3+3NH4OH -->Fe(OH)3+3NH4Cl

I just ate dinner, so I whipped that out in like 2 minutes. Guess I got beat to it.

[Cmdrmack]

Just learn you polyatomic ions and you'll be fine.

[Omega]

Don't forget molar mass, reactivity series, and oxidation numbers!

Edited by Omega, 07 May 2008 - 04:16 PM.

[SHADOW HUNTER ALPHA]

Also, PLEASE fix you spelling and grammar. You are a new member and writing poorly isn't going to let you stay here long.

Not saying I'm a vet or something, it is that I've been here longer than you.

He was here over a year before you, Lynx. Also, you may want to check your own post for spelling and grammar.

I haven't done this stuff yet, so I might as well be prepared. Can anyone explain the second equation, because it looks like you're all randomly switching numbers. What is being balanced and how do you balance the equation (my chem class sucks for me not to learn this)?

[Omega]

Well, Alpha, an equation isn't balanced until there are the same number of each kind of atom on each side. For instance, take one of the problems:

Al2(SO4)3+Ca(OH)2 ----> Al (OH)3+CaSO4

On the left side of the equation there are :
2 Al atoms
3 S
14 O
1 Ca
2 H


On the right side,
1 Al atoms
7 O
3 H
1 Ca
1 S

For an equation to be balanced, there need to be the same numbers on the right side of the equation, too. If there were fewer, that would be disappearing matter, which is a HUGE no-no. If there were more, that would be matter from the air, which is an even bigger no-no.

However, we are not to futz around with the actual chemical formulas. We can only change the amounts in which they occur, so we switch the coefficients. For instance, you could have:

H2O ---> H2+O2

But that isn't balanced! There's one more O atom on the right side than the left! So we change it to:
2H20 ---> 2H2+O2

See? We didn't change the chemical formulas, just the amount in which each substance appears.

To balance an equation, you change the coefficients so that the number of atoms of each element match on both sides of the equation.

FIRST: Balance the metals.
SECOND: Balance the nonmetals.
THIRD: Balance hydrogen.
FOURTH: Balance oxygen.
FIFTH: CHECK YOUR WORK!!!! Make sure that you didn't unbalance anything you balanced before. You might get some pretty ridiculous stuff going on when you balance equations.

So, the correct answer to that problem I mentioned earlier is:

Al2(SO4)3+3Ca(OH)2 ----> 2Al(OH)3+3CaSO4

On the left side of the equation there are :
2 Al atoms
3 S
18 O
3 Ca
6 H


On the right side,
2 Al atoms
18 O
6 H
3 Ca
3 S

Voila! Same number of atoms for each element on both sides of the equation. That's how you balance.

Just remember to balance metals, then nonmetals, then hydrogen, then oxygen, and then make sure it's all balanced.

Have fun!

The second equation works out like this:


FeCl3+NH4 OH--->Fe(OH)3+NH4Cl
Fe 1|1
Cl 3|1
N 1|1
H 5|7
O 1|3

BALANCED:

FeCl3+3NH4OH -->Fe(OH)3+3NH4Cl
Fe 1|1
Cl 3|3
N 1|1
H 15|15
O 3|3

You switch coefficients until the equation is balanced. That's all that it is.

Edited by Omega, 07 May 2008 - 05:05 PM.

[Uncle Hammer]

Omega I don't mean to challenge your methods, but that seems a little over complicated. Balancing chemical equations is in no means done in order of groups and families. It's a fairly simple process of just making sure you have the same amount of everything on each side. Doing it your way just wastes time and adds confusion. The only time steps are taken to balance is when your dealing with redox/acid/base reactions. Anyone taking the AP chem test this Tuesday?

[Omega]

Well, yeah, that method is over-bloated. Of course you wouldn't write all of that out on an actual test, but that's the long way around. The way I see it, that's just going through all the steps. Once you understand the concept, you start using shortcuts, or even just seeing the answer right off the bat.