anyone good at chemistry?

[SplshMtnLvr28]

i've been struggling lately in chemistry, and i don't get tonights homework at all, so i'd really appreciate it if someone could help me understand it.

right now we're doing limiting reactants and calculations involving a limiting reactant. my chem book shows how to determine which reactant is limiting in the equation and then solve it, but i just don't get it. so yeah :

For each of the following chemical equations, suppose that exactly 15.0 g of each reactant is taken. Determine which reactant is limiting, and calculate what mass of each product is expected. (Assume that the limiting reactant is completely consumed)

2Al + 6HCl ---> 2AlCl3 + 3H2

(i balanced it already)

if you could just explain to me how to figure out the limiting reactant, then the get the masses i'd really appreciate it. thanks a lot!

 

[VMK_MagicalLadee]

Alright so.
Here we go.

Find moles with your 15.0 grams. n=mxM
Then, set up a mole ratio ( do you know how to) to find out your moles given.
Then use another mole ratio with your newly found moles, and find out how much you need.

If one reactant has more than needed, its in excess and the other is limiting.
If one is not enough, then IT is the limiting reactant.

 

[TinkerTracy]

Chem was my worst subject....EVER
good luck!

 

[Addicted.to.Speed]

Stupid question for chemistry but,

But how do you find the mass of one molecule of H20, like i know that you add up those atomic masses (of H and O), but is that the answer or do you have to do something else to it????

 

[VMK_MagicalLadee]

H is 1.01( times it by 2, theres 2 hydrogen atoms) and O is 15.9994. Just add them. =]

 

[2HOT2touch]

its 18.02. we pretty much had to know that one by heart. I miss Chem. I HATE physics.

 

[KidGoofy]

Im taking it too but the only reason i am passing is because the teacher likes me. Also I am a really good guesser

 

[Addicted.to.Speed]

Thank you very much

 

[minniesBFF]

I'm supposed to be studying for my chem test tomorrow, but instead I'm on here. So I'm pretty much gonna fail. xD

 

[VMK_MagicalLadee]

xD

I have CHEM 2nd period today. We're doing a lab. =]