Moles

moles = mass/molar mass

 

It's quite simple if you just remember that you're dividing the mass of what you have by the mass for one mole, hence finding how many moles there are. For example if you have 18 grams of water, which contains two hydrogen atoms with r.a.m of 1 each, so 2 in total and an oxygen atom, with r.a.m of 16, giving a total r.a.m for water of 18 grams, the number of moles = 18grams of water/18grams per mole of water = 1, so there is one mole in total.

 

Funny, we're doing the exact same thing in school. We've been doing it all year too, and I JUST figured it out.

And next week, school ends. :l

 

I swear you were in year 10? We don't do molars or whatever the heck they are yet

 

Moles argh. Could never ever get my head around them.

 

What did Avogadro teach his students in math class?


Moletiplication

my chem teacher always told mole jokes. they're hilariously tacky. oh but i do hate chemistry.

 

So I won't lie, I thought this was going to be about the animal. I was like what an odd thread.

 

An easy way to solve the issue is to use units. mass (g) / molar mass (g/mol). The grams cancel out, and you're left with moles.

My chemistry teacher took off points for not using units for just this reason. If you use units, and they don't work out in the end, you know you've done something wrong. If you just use numbers, and tack on the correct unit assuming you're right, how do you know if you've missed something?

 

ah same with my teacher, although remember that they're all technically fractions; even the measurements like grams because its mass (g)/1 so that you don't forget that the (g) part of the molar mass will have to go in the denominator in order for them to cancel out, or you will have to put another conversion in between those two parts. if you work with fractions like this, you will always know when you're done because there will only be one label left in the equation (or possibly two that combine into one kind of measurement)

and the reason i hate chemistry is because that is one of the more simple concepts