To reduce, or not to reduce, that is the question...

Hello dear readers, thank you for visiting again to read our newest posts on Chemistry.

First off, you might think that today is one of those math-brain-attack days where your brain automatically  freezes after viewing our blog post. It's alright, we get that kind of feedback all the time, so you're not alone on this. Today's lesson will definitely involve less math in comparison to mole conversion (as far as I know, anyway...)

On first glance, it would seem that the following topics are focused on math, as opposed to chemistry. This is only partially true. Let's say in math, if you don't reduce a fraction on a test, you will lose marks unless your teacher is an incompetent nincompoop. However, on a chemistry test, it could be a completely different scenario. You may possibly even earn marks for not reducing the fraction...in a sense.

Empirical formula
All compounds have an empirical formula. What this means is that the compound is written with the lowest ratio of atoms in the compound. For example, we know that Glucose is C₆H₁₂O₆.
The ratio of its atoms are 6:12:6. In lowest terms, this would be 1:2:1, therefore the empirical formula of Glucose is CH₂O.



On the other hand, Molecular Formula is then the "not-in-lowest-terms" form of formula writing for compounds. And this form of writing states the exact number of each atoms contained in a certain molecule.

Let's try having a brain freeze now,


For example:
Given the molecular formula for butane is C4H10
What is the empirical formula of such?

[First, you look for the greatest common factor/divisor of 4 and 10, which is 2.]
[Then , divide both numbers by 2, you will get 2 C's and 5 H's]
[Ta Da]
[You answer should be: C2H5]

These formulas below you may want to must keep them closely in mind when a test date comes along,

Molecular Formula = Empirical Formula  x a Whole Number 
Molecular Formula Mass = Empirical Formula Mass x a Whole Number
Mass of one mole = Empirical formula Mass (g) x a Whole Number

Moving on ... don't worry you will have a 'brain melt' sooner than you think.

So,  how do you determine the empirical formula given the masses of each atoms???

The Million Dollar Question here today is: Determine the empirical formula of Ca, O, and H given 13.5g of Ca, 10.8g of O, and 0.675g of H. {Now, get out some scrap paper, folks and give this question a try. Stay tune for full-solution.}

1) Make friends with mole (unless you want your arm to be bitten off...the decision is entirely up to you)
                      1 mol Ca       
13.5g Ca x     40.1 g Ca         = 0.337 mol Ca

                      1 mol O          
10.8g O  x     16.0 g O          = 0.675 mol O

                      1 mol H       
0.667g H x     1.0 g H           = 0.667 mol H

2) Divide each value of mole by the smallest number of moles calculated when friend-making with moles.

 0.337     mol Ca  => 1.00
 0.337

 0.675     mol  O  => 2.00
 0.337

 0.667     mol H   => 1.98 ≐ 2.00
 0.337

3) Brain Melt time...

The final answer to the 'Million Dollars Question' is CaO2H2 and you can also present your answer in this form: Ca(OH)2 and the million dollars will still be awarded to you!
Are you the ultimate winner of the million dollars tonight?