<p>Okay I missed today class and we talked about moles, or mole, or however you say it. I heard they are really confusing and I need to learn them ASAP before I go back. So could anyone explain them or link me to a good chem website that will teach them to me?</p>
<p>This is all over the intertubes, please perform a Google search.</p>
<p>However, I like chem, so I will explain a bit:
A mole is a unit of measure in the same way a dozen is. If you understand what a dozen is, you understand what a mole is. 1 dozen = 12 and 1 mole = 6.02<em>10^23. If I have two dozen, I have 24. If I have 2 moles, I have 12.04</em>10^23.</p>
<p>You generally use moles to talk about how much of an element or compound you have (e.g. I have 1.2 moles of carbon). You can then use that amount to figure out how many grams of the element/compound you have. (e.g. 1.2 moles of carbon, carbon = 12g/mol, therefore: you have 12*1.2 grams of carbon).</p>
<p>Alright… here’s the concept of the mole.</p>
<p>Used for counting in chemistry.
6.02 x 10^23 is Avogadro’s Number. </p>
<p>For any substance such as NaCl… let’s say you have 3.5 moles NaCl.</p>
<p>You can use Avogadro’s Number to go from moles to representative particles (Atoms, Molecules, ions, there’s a lot).</p>
<p>For 3.5 moles of NaCl you have</p>
<p>(3.5 mol) (6.02 * 10^23 molecules)/(1 mol) = 2.1 x 10^24 molecules NaC;</p>
<p>@CranberryOrange I learned not to trust everything I find on the internet…ironic isn’t it?</p>
<p>@MIT That was confusing…where did you get the 3.5 from?</p>
<p>It was an arbitrary number.</p>
<p>just came up with it.</p>
<p>Btw… most science articles on wikipedia are valid.</p>
<p>So if I get this right…you find the atomic weight of each element in the substance…find the total weight of the substance…which in in moles…Then you times it by Avogadro’s Number. Then you find out the molecules?</p>
<p>Molar Mass is the proper name.</p>
<p>And the thing depends on what you want.</p>
<p>If you want mass and are given moles.</p>
<p>moles * molar mass.</p>
<p>if you want moles and given mass…</p>
<p>mass / molar mass.</p>
<p>You have to know how your units cancel out.</p>
<p>What’s the difference between mass and molar mass?</p>
<p>molar mass means mass unit per mole, or grams per mole.</p>
<p>Molar mass is what you get on the periodic table.</p>
<p>Molar mass is the mass of one mole of an element. Mass can refer to any amount of anything.</p>
<p>THIS IS SO CONFUSING! </p>
<p>Okay I am going to use an example: H2O The molar mass would be 18grams right? What would be the regular mass?</p>
<p>It depends on how much water you have</p>
<p>Yes, molar mass is 18 grams.</p>
<p>Can’t know the mass unless we know how much you have in moles, volume at STP… something.</p>
<p>That’s the purpose of stoichiometry.</p>
<p>1 mole equals 1 furry animal.</p>
<p>OH! So mass is the actually physical mass! I get it I thought were still talking on molecule</p>
<p>The molar mass (18 grams in this case) is the number of grams in one mole of whatever substance you are talking about.</p>
<p>2quarts of water would the molar mass still be 18?</p>
<p>Yes. </p>
<p>Molar mass is constant regardless of the Physical amount you have.</p>
<p>No one user quarts of water in Chemistry.</p>
<p>So 90grams of water?</p>
<p>MIThopeful16 already answered your question.</p>
<p>“Molar mass is constant regardless of the Physical amount you have.”</p>