Monday, March 11, 2013

Week 23: Empirical Formulas and Applying Constant Ratios.

 Everyone knows Water is H2O right? How did we figure out that it was a 2:1 ratio in the first place? Well, Water ( H2O) as most know it is actually in its impirical form. Empirical form Is where the Lowest ammount of Atoms is expressed while stil maintaining to show their Constant Ratios. H2O has two hydrogen atoms and one oxygen atoms because while Oxygen is heaver and outweighs Hydrogen, the Molar Mass of Hydrogen is 2x that in oxygen in this compound. Knowing the Empirical Formula is super important!

Another Formula that we learned this week was the Percent Composition Formula, which taught us to figure out just how much of  each element was in the compound, the formula is the Molar Mass of the element over the Molar Mass for the entire compound multiplied by 100, For example if one wanted to find the percent of Oxygen in H2O one would put Oxygen's molar mass ( 16g/ mol) over the total Molar Mass of the compound ( 18g/mol) so the formula becomes 16/18 x100 which is 89%, so Oxygen makes up 89% of the compound water.

The final big, new thing we learned this week was how to put empircal Formulas to use. If you know how many  of each atom is needed to make a compound, you can multiply it by ANY NUMBER and still find the answer. We were testing this idea with NH3 in class. Mr. Abud was doubling or tripling the numbers and i was kinda perplexed because not everything is so simply doubled. He said that was the next step because not everyting in Chemistry is textbook perfect, or all even numbers. We tried working with decimals and found  that when multiplied by a deciaml theratio between the N, The H and the NH3  remained unchanged, i really felt likei grasped the concept because that day there were a lot less ppl in the class and the class felt more personal. I hope we delve further into this topic as i really find this interesting and fascinating as the  ratios do actually remain constant

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