Chemisty Help? x.x

[Ex.plode]

Heyy, Just wondering if anyone could help me out with the terms

Empirical (Simplest) Formula

&

Molecular (True) Formula

I've tried google, but I want a more relaxed/easy to understand definition if I can get one~

[Lukasz_Lucky]

Heyy, Just wondering if anyone could help me out with the terms

Empirical (Simplest) Formula

&

Molecular (True) Formula

I've tried google, but I want a more relaxed/easy to understand definition if I can get one~

Empirical formula is pretty simple to understand. It's the simplest formula you can get for a molecule. I will give some examples.

Let's you have the Glucose formula which is C6H12O6
If you want to simple it, you will simply have to divide all the numbers by the highest common number of them all. In this case, it will be 6. So your simple formula for the glucose molecule will be CH2O

Now, you have to be careful. You can divide by numbers which aren't common to all. If you divide by 4, you can, but it won't exactly be the simplest empirical formula.
You would write, in this case, C6(H3)O6.]
So it's better to find a whole common number which fits for all.

H2O is already in it's empirical formula because you can't divide the numbers anymore.
Sulfur is S8. You can get this one simple by dividing by 8 so your empirical formula will be S.

Molecular formula is the real formula. For Glucose, the molecular formula would be C6H12O6.

Simple as that.

[lolznplz]

in my class, when we started doing empirical, we started from a percentage, and there's a nice little poem to remember it.

percent to mass
mass to mole
divide by small
multiply till whole

1) so basically you change the percent to mass (assuming you use a 100g sample, simply change the % sign to a g)

2) multiply the mass by the atomic number (e.g. oxygen is 16.00). do this for each element.

3) now divide each of your products by whichever was the smallest.

4) multiply any that aren't whole numbers (or close to whole numbers, seeing as empirical is very rough) to make them whole. so if you had a number that was 2.5 after step 3, multiply it by 2 to get the whole number 5.

that last number is the subscript for the element you worked it out for.

so say you have 23% oxygen and 77% carbon
23% = 23 g
23/16.00 = 1.4375/1.4375 = 1

77% = 77g
77/12.01 = 6.411/1.4375 = 4.46, close to 4.5*2 = 9
so you get C9O

edit: to get molecular formula, you have to find N
to get N, you divide the molar mass of the molecular formula by the molar mass of the empirical formula (at least i'm pretty sure molecular goes on top). usually the molecular formulas mass is given in the question if you have to get to empirical first.

once you have N, you simply multiply the subscripts from the empirical formula by it.
EX:

156 gasdfasdfasfdasfasdf156 g is a random number that would be found in the description of the question
----------------------- = 1.257 = Nasdfasdfi can't remember if you have to multiply N until whole.
(12.01*9) + 16.00

N(C9O) =

[noddalives]

im a biochemisty major and your explanation confused me bigtime lolznplz

its better to go with the first explanation as im assuming youre still in school, otherwise youd already have a grasp of empirical and molecular formulas.

in basic terms its exactly what the name says(and i stole the glucose explanation >.>):
Empirical (simplest)- the formula in its simplest form eg. C6 H12 O6 becomes C H2 O
Molecular (true)- is the formula as the basic structure exists in non tampered form eg. C6 H12 O6 is C6 H12 O6

[lolznplz]

i tried to keep it simple, but that's tough over the internetz i guess.

i'm in grade 11, and we went right from percent composition to empirical formula.

[mokaiba]

Heyy, Just wondering if anyone could help me out with the terms

Empirical (Simplest) Formula

&

Molecular (True) Formula

I've tried google, but I want a more relaxed/easy to understand definition if I can get one~

X=2. :eek: