General Category => General Board => Homework Haven => Topic started by: -shiNe! on January 31, 2011, 08:12:28 PM
Title: Mols?
Post by: -shiNe! on January 31, 2011, 08:12:28 PM
For Chemistry, how do you find Moles? We have to convert mols to grams for what we are doing right now, or grams to mols.
Title: Re: Mols?
Post by: Lucky on January 31, 2011, 08:18:10 PM
Ask Edi! He explained it to me in like 2 minutes and I understood it better than a semester of studying it :P Unfortunately, at the said time Edi was explaining it to me I was cramming for a mid-term, so I have forgotten it enough to the point I wouldn't feel comfortable explaining it :P
Title: Re: Mols?
Post by: TUR80 on January 31, 2011, 08:37:08 PM
um moles well you dig a mole out of the ground and weight it and convert the weight into grams
Title: Re: Mols?
Post by: -shiNe! on January 31, 2011, 08:56:45 PM
Unfortunatly I have no Idea who Edi Is
Title: Re: Mols?
Post by: BFM_SirTaco on January 31, 2011, 09:29:19 PM
hey there
so here is a quick run down
a mole (shortened to mol by some chestry teachers) is a unit of measurement. Now a mole is not a weight or a unit of length, rauther a mole is a set number. the value of a mole ir roughly 6.022 x 1023
this number is based on the number of ATOMS (please note that atoms are a COUNTED value) in 12.000 grams of carbon. This is called Avogadro's constant or number. So for instance if we were to count the number of atoms in 12.000 grams of carbon we would come up with roughly 6.022 x 1023. I hope you are following me so far.
now if you look at your periodic table you will see the symbol for all the elements. if you find carbon, under it you will find the number 12.000. Now this value has been disputed and will sometimes say 12.011 or something very close so check with your chemistry book before continuing. This number and all the numbers directly underneath their their respective element symbols represent how many GRAMS of an element there are when ONE MOLE of particles of the element are weighed.
lets try an example:
you teacher asks: how many grams of Magnesium will i have if i have 2.35 mols of magnesium.
first you would find magnesium on your periodic table and see that there are 24.305 grams of magnesium for every mol and then you would simply multiply 2.35 mols by 24.305 g and end up with 54.7 grams of Magnesium (notice i used my significant digits or figures to round my final answer).
similarily it works the same way around: you get the question, "i have 500. g of lead how many mols of lead do i have?" and you would divide 500. g of lead by 207.2g lead (which is the number of grams of lead in one mole of lead) and get 2.41 mols of lead (notice i again used my significant digits or figures to round my final answer)
any questions feel free to post....
alternatively you could watch this catchy video with a song that will get stuck in your head and you will never forget what a mole is
http://www.youtube.com/embed/1R7NiIum2TI
Title: Re: Mols?
Post by: BFM_Zakk on January 31, 2011, 09:31:14 PM