Mind helping me to solve this stoichiometry problem?

**Puffin** · 10-14-2010 05:23 PM

According to my teacher, it's easy, but for my whole class, it isn't.

Unknown element X combines with oxygen to form the compound XO₂. If 44.0 grams of element X combines with 8.00 grams of oxygen, what is the atomic mass of element X?

A. 16 amu
B. 44 amu
C. 88 amu
D. 176 amu
E. 352 amu

I'd appreciate the help and preferably a quick explanation, because no one understands it and our teacher is giving limited hints out. Thanks.

**SnakeCharmer** · 10-14-2010 05:43 PM

X + O2 --> XO2

m (O2) = 8 g
M (O2) = 32 g/mol

This means that 8/32=0.25 moles of oxygen reacted with 0.25 moles of X

m (X) = 44 g is equivalent to 0.25 mol of X

Atomic mass of X should be 44/0.25 = 176

EDIT: sorry M(O2) = 32, not 16 like I originally wrote

**Puffin** · 10-14-2010 05:47 PM

Thank you!

**Philosopher8659** · 10-14-2010 05:50 PM

Well I would have done it simpler.

For a one to one correspondence, O2 would be divided into 2, or 4 to 44 which is 11, then simply multiply. 11 x 16 for 176.

4 is to 44 as 16 is to 176.

**Xei** · 10-14-2010 09:49 PM

I'm not sure what we should do about these kind of threads.

I don't have any problem with answering general questions, but when it gets to basically doing homework for people... I'm not so sure that's a good idea.

Plus it's not really extended discussion... perhaps there should be a subforum for this kind of thread? Thoughts?

**Philosopher8659** · 10-14-2010 10:32 PM

I am not too keen on overly established formalities that really boil down to subjective non-sense. What is homework but the instilling of ideas to begin with? It often happens that one lacks the conception expressed in an idea, and thus makes faulty judgments. Best to err on the side of liberality than of stupidity.

**Puffin** · 10-14-2010 10:47 PM

Originally Posted by Xei

I'm not sure what we should do about these kind of threads.

I don't have any problem with answering general questions, but when it gets to basically doing homework for people... I'm not so sure that's a good idea.

Plus it's not really extended discussion... perhaps there should be a subforum for this kind of thread? Thoughts?

I'm not big on it either, but that's why I asked for an explanation so I understand the concept. And this is in Science and Mathematics, which is appropriate. As for it being in extended discussion, well... :p

**Philosopher8659** · 10-14-2010 11:01 PM

If you keep asking for understanding, you just might end up a philosopher, then watch out. big trouble.

**Xei** · 10-14-2010 11:01 PM

You weren't really told how to do it though, you were just given the workings... I'd much rather somebody said something like, 'what two things do you need to work out the atomic mass?', 'how can we obtain these from the question?', etcetera.

**Philosopher8659** · 10-14-2010 11:02 PM

Oh crap, not only where to say something by how. I don't have a gun, so I will just ask for an explanation on how to shoot myself without a gun.

**Xei** · 10-14-2010 11:06 PM

I have no idea what you're talking about, but you should understand as always that I wasn't talking to you anyway, I was talking to the original poster.

**Philosopher8659** · 10-14-2010 11:09 PM

Pardon me, I was misled into believing this was a forum. Not a twosome. Besides, I have adopted her as my soulmate, it is called virtual perversion.

**Xei** · 10-14-2010 11:15 PM

There's a difference between being free to talk to everybody and being obliged to, and I found your comments on my conversation incomprehensible so I thought I should let you know that I'm not replying to them.