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Stoichiometry

I was looking around Instructables and saw many chemistry related Instructables, so I thought one on stoichiometry would help. Basically stoichiometry (my definition) is the study of amounts in relation to a chemical reaction. Stoichiometry is the base for all modern chemistry. The method I'm going to use is like a flow chart opposed to the "railroad tracks" that is taught by most teachers and books.

This Instructable is good for people who are just learning stoichiometry and those who want an easier way. This is also great for all those people who like to use chemical reactions to blow stuff up. You can find the right amount to optimize the reaction and save reactants so you don't waste money.
 
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Step 1: The mole

At the center of stoichiometry is the mole. The mole allows a chemist to find what masses of substances to use in a reaction.

One mole is an amount of a substance that contains 6.022×10^23 atoms. To help you understand how astronomically big this number is if I gave everyone on Earth (estimated 7 billion) $3 million dollars a day; I could keep handing out money for 78564 years. Yes that is right. Almost 80 thousand years.

There are many different ways to find moles depending on what you are working with. For solids or liquids that aren't solutions its sample mass/molecular weight=moles. Use a periodic table to find the molecular weight.  For example to find one mole of lets say carbon-14 the equation is x/14=1 
x=14grams
Another example: Find 5 moles of H2O.
x/18=5
x=90grams
Find how many moles are in 20g. of NaCl.
20/58=x
x=.345

I think you can get it from that.




STEMsheets6 days ago

This site has balancing chemical equation worksheets for extra practice balancing equations: http://stemsheets.com/science/balancing-equations-worksheet

seanroberts4 years ago
"6.022×1023" 6.022×10 ^ 23
joosh (author)  seanroberts3 years ago
Yeah didn't notice that. When I wrote it up I used an exponent, but it did show up I guess. Thank you :)
pborstel4 years ago
In the NaCl example, how did you determine the molecular weight of NaCl to be 28?
joosh (author)  pborstel4 years ago
Uh oops thank you :) I was going through it fast and used the number instead of weight.
pborstel joosh4 years ago
Ok, so 58?
joosh (author)  pborstel4 years ago
Yep, that one should be right unless my arithmetic is way off. If you are wondering about any molecules just look on a periodic table for the weights of each element and add them up.
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