The Basic Chem Thread(Noobs should read this)

In this thread i'll attempt to teach you some basic chemistry. This is mainly for the noobies, but it might serve some of the more experienced aswell. If you know anything about chem, help me out with writing this Smiley.

Now, to get down to business. Chemistry is a very important part of our lives. It gives us oxygen to breathe, gives us energy to move, converts protein into muscle, deposits calcium into our bones so we can stand and walk up right, etc.

First, lets start with the elements, since anything smaller then this isnt as important as these, and the average person wont need to deal with or have the technology to do so if they want to.

The lightest element is Hydrogen, with a mass of 1. The second lightest is helium, which is essentially 2 hydrogen atoms fused together. Elements can exist in different states, such as solid, liquid and gas. Plasma is considered the fourth form of matter, although many people consider it not. Plasma is essentially ionized gas, such as fire. Solid is hard, like wood, steel, etc. Liquid is like water, mercury at room temperature, etc. Gas is like the air we breathe.

http://www.webelements.com/

This link has the basic elements, and you can click on them to see more details, etc.

Secondly, when dealing with chemicals, you want to have a perfect mix of chemicals, to prevent waste, prevent contamination, and make it easier to clean the final product. Every chemical is measured in moles. This is the number of a given molecule per a given amount of substance. Wikipedia can probably explain it better then i can, so i shall let it do the talking for me. Smiley

http://en.wikipedia.org/wiki/Mole_(unit)

You probably thinking " Huh ", so let me explain by giving an example from a previous thread.

There are 6.02x10^23 molecules of a given substance per 1 mole.

To figure out the moles of a given weight of substance(assuming pure) you go;

n = m/M

n= number of moles(you want to know this)
m = mass of substance
M = molar mass of substance

I.E. Oxygen is 16.

So, in 1000g of oxygen

1000/16 = 62.5Moles. Or 62.5 x (6.02x10^23) molecules of oxygen.

To figure out things with more then 1 element, you use this way;

Assuming 150g of H2SO4.

H = 1
S = 32.06
O = 16

So (2x1) + (1x 32.06) + (4 x 16) = 98.06

Therefore, we have

150/98.06 = 1.5296757087497450540485417091577 moles of a given substance.

If you know the number of moles, but want to know the mass in grams, then

m = n.M

m = mass
n = moles
M = Molar mass(all the same as above)

10 moles of oxygen

m = (10)(16)

m = 160.

It's simple enough. Just substitute the letters for the relevant numbers, and walla, you have the numbers you seek.

Aaaaaaaand; a link for your viewing pleasure;

http://www.ausetute.com.au/massmole.html

Hmmmm.....what next?

Balancing equations.

A link, first this time;

http://richardbowles.tripod.com/chemistry/balance.htm

This is where it starts to get tricky. You might think "oh, lets just mix a + b and walla, we have c. Wrong. Remember how i said you want to minimize waste? This is where you need this section. Lets give a really simple example.

Hydrogen + oxygen= water; or;

H2 + O2= H2O

Now, this might seem easy, but look at the numbers next to the H and the O. Notice how their both 2, yet in the end product it's only 2 and 1? Thats because elements like H2 and O2 exist normally in pairs. Now, to balance this, all you need to do is;

2 H2 + O2 = 2 H2O, for a total of 4 hydrogen and 2 oxygen on both sides. Simple, no? Thats right, it isnt. Try it on something a bit harder, maybe.....

Al + O2 = Al2O3; So;

4 Al + 3 O2 = 2 Al2O3 (4 Al on both sides, 6 O on both sides).

Now, you need to know atomic weight, since you(ideally) would use the same amount of material as the above ratio, except it isnt as simple as 4g of Al and 3g of O2.

Aluminium has an atomic weight of 27. 4 Al has a mass of 108.
Oxygen has an atomic weight of 16.(per atom) 6 O2 has a mass of 96.

Now, if my memory serves me right, you need 108g of aluminium and 96g of oxygen to make 204g of aluminium oxide, Al2O3.

Now, a little bit more oxygen definitely isnt going to hurt, since solid oxygen is rather rare(im pretty sure it only exists as liquid, gas and plasma, but not solid).

Now that i have hopefully explained this to the best of my ability and largely from memory(so it is bound to be flawed), i want anyone who even bothers to read this to help finish writing this, just add a post, add some links, whatever. Just bring discussion to this thread, otherwise SF will go down the drain and i'll be stuck with no good science forums to lurk .