CGPwned: Balancing Equations Crash Course!

Here's my take on balancing equations - the cgpwned way ;)

Enjoy! Hope this helps!

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  • Created on: 14-03-12 13:06
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BALANCING EQUATIONS ­ THE CGPWNED CRASH COURSE!
How do you balance equations? Student Answer: I don't know. Dude, its not an exam question.
Anyways in this section I shall try to explain how to balance equations!
INTRODUCING CHARGES
Ions are atoms that carry either a positive or negative charge. Compounds are electrically
neutral. Therefore, in an ionic compound there must e the right number of each sort of ion, so
that the total positive charge exactly cancels out the total negative charge. It's math
basically. This sounds confusing but it gets easier later...somehow.
Charges depend on the number of electrons on the outer shell. Group one metals have one.
Group two metals have two...etc
Group Charge
Number
1 1+
2 2+
3 3+
5 3-
6 2-
7 1-
8 0 <- Therefore they are inert
Note: Group 4 can produce an unpredictable pattern an is beyond GCSE level ­ according to my
huge Edexcel textbook.
Some of the names of compounds tell you the charge. Iron(III) chloride contains the iron with
the 3+ charge. Copper(II) sulfate contains a charge of 2+. Some transition metals need to be
learnt...
These are some ions that would help if you learn it (ew).
Charge Substance Ion
Positive Zinc Zn2+
Silver Ag+
Hydrogen H+
Ammonium NH4+
Negative Nitrate NO3-
Hydroxide OH-
Hydrogencarbonate HCO3-
Carbonate CO32-
Sulfate SO42-

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BALANCING A COMPOUND
If Chlorine is Cl2, then why is sodium chloride NaCl? Why not NaCl2? Well here's the thing.
Before even trying to balance an equation, you need to learn to balance a compound. But how
do you do it? Simple. We now know the charges (or at least I hope its we and not me). To
balance a compound, we need to make sure that the charges of each element add up to 0.
Sounds confusing? You bet...…read more

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Get it now? NO? okay I give up. If you do, then move on...
BALANCING EQUATIONS
Now it's the fun part! No...
Look at this:
2Na + Cl2 -> 2NaCl
Now let me remind you that on its own, any diatomic molecule must be written as element2.
However this also means you'd have 2 x the element. That's true, that's why you need
balancing. The Cl2 in the equation currently has a total of 4- charge. Na only has 2+.…read more

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Na + Cl2 -> 2NaCl
2 sodiums (total charge of 4+) + chlorine (total charge of 4- because of the diatomic molecule
thing) -> 2 sodium chlorides
Get it? At least understand it abit more? Okay let's try writing our own one! Lets write the
reaction between potassium and water.
Now we know that when potassium reacts with water, you get potassium hydroxide and
hydrogen, so lets figure out the balanced compounds and write them down first.…read more

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We know that Cl2 has to have that `2' because it is a diatomic particle and starts off by itself.
We also know this means Cl2 starts off with a charge of 2 x (1-), or a total of 2- charge. Lithium
only has a charge of 1+.
Lets use some common sense here. We know that lithium will react with chlorine to make
lithium chloride. Lets write that out in balanced form.…read more

Comments

Hannah

thank you x

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