[Bobboau]

ok, so I got a test back today in my chemistery class, and I just barely got a d (69%). 10% of that came bacause I couldn't remember the life story of Ernist Ruthiford and every experiment he ever performed. this has _nothing_ to do with an understanding of chemistery but I digress... the thing that's realy got me unable to sleep now is this. there was a 5 point question pertaining to part of a limiting reactant problem, I honestly **** up the first part, I wrote down aluminum oxide as AlO, when it should have been Al2O3, so starting off with the wrong (but balenced) formula of
2AL + O2 -> 2AlO
and told that I had a mass of aluminum and oxygen that I can't remember (I think it was something like 80g Al and 117g O2, that isn't the right number but we'll go with it because it proves the point) I need to find the limiting reactant. the way the teacher want's it done is thus:
convert mass to moles of each reactant then find the potential moles of one of the products useing those moles assumeing everything else is in exsess, for each reactant, then compare the moles of that particular product between all the reactants and find the one that is smallest and that is the limiting reactant.
what I did was:
I find the number of moles of each reactant, treating the reactant as a whole unit, that is I treat 2Al as two alluminums, I get the moles of each of these and compare them, in essence I assume one 'product' is made and the ratios tell me how much of each I need to make it.

her math would go as such:
80(the mass of the aluminum)/27(aproximation of the atomic mass of aluminum)=2.96(moles of aluminum)
2.96*1(for every Al atom I get 1 AlO)=2.96(moles of AlO)

117(mass of the oxygen)/32(molecular mass of O2)=3.65(moles of O2)
3.65*2(for every O2 molucule I get 2 AlO)=7.31(moles of AlO)

2.96(moles from AL) < 7.31(moles from O2) -> Al is the limiting reactant


my math is as follows:
80(mass of the aluminum)/54(mass of two aluminum attoms)=1.48(moles of 'product' (product in this case is 2AlO))

117(mass of the oxygen)/32(molecular mass of one oxygen molocule)=3.65(moles of 'product' (2AlO))

1.48(from aluminum)<3.65(from oxygen) -> Al is the limiting reactant

I came to the same answer with a diferent, but logicaly sound reasoning, the only thing I did diferent is I factored out the ****ing two as to not do twice as much unnessisary math. in her defence I didn't write out a product of 2Al anywere and as soon as I found the mass of aluminum and started to do the division I realised it was already smaller than oxygen so I just wrote out'/2 would be even smaller' and didn't actualy write out 1.48. I spend nearly all hour trying to explain it to her, and I get the destinct impression she didn't beleive me and thought I was trying to BS my way out of it. now she says 'I'll ask some of the other teachers there oppionions and see what they say' and I'm ever-so-sure she's going to actualy explain my point properly and not simply tell them I did it wrong.

GODAMNIT I HATE IT WHEN I"M RIGHT BUT PEOPLE WON"T LISTEN TO REASON!!!

I got the right ****ing answer! every other class in this damned school showing work only gives you partal credit if you get the wrong answer. but errr 

[MatthewPapa]

i hear ya dude,

I had one like that back in high school

she ate my lunch (and my GPA)

and for some reason all chemistry teachers shun shortcuts, both logical and mathematical

[Polpolion]

[grammer nazi] Why did you use quotes instead of apostaphes in that line? must have been holding down shift [/grammer nazi]

I have a GPA of 4.0!

Of course I'm a freshmen (Freshman?) in HS and I've been in school for about two weeks...

[Sarafan]

I got the right ****ing answer! every other class in this damned school showing work only gives you partal credit if you get the wrong answer. but errr 

You see, this is how the world works, people (specially teachers) dont and wont admit that you're right simply because it will show that they dont know a thing in the first place.

[Mars]

I have a GPA of 2.5... and I don't ****ing care.

[Dark Hunter]

i hear ya dude,
I had one like that back in high school

Ditto. My chem teacher is absolutely by-the-book. Silly thing is, she came from teaching a college class to a high school class... not sure whether that's a step up or down.

Heh, she tried, at first, to get us to take notes a certain way; you know, one of those "note-taking techniques" they teach kids at study skills class. My entire class resented this (we hate being condescended to), so we refused to take notes in said manner, and got all A's on the first series of tests.  

She stopped attempting to make us do that....

[Nuke]

school is a waste of time, there are other ways to learn that dont cost you anything. read a non-fiction book every week, take an aprinticeship (and you get payed for it too), join the military (as they cram just the facts into your head, not the bull****, and pushups to you if you get the wrong answer). when i got my degree, i didnt take notes, i read only the required material, and i ocasionally skipped class to go partying. i dont think i learned anything new. seems every new grade is a repitition of the past one. ive learned more from casual use of wikipedia/the history channel/mythbusters than i ever did from school.

[Axem]

I had teachers that were pretty lenient about wrong answers as long as you tried.

Except for one. And to make it even better, he couldn't teach. So the whole class was trying to understand what he says before he goes off on a tangent to explain it in more "simple" terms. Oh and playing bingo with the 20-some phrases he would use daily.

[Flaser]

We had a chemist teacher who could qualify as a sadist....except we liked him for being hard on us.

For that matter he wrote the very book he teached from, as well as knew his work like the back of his hand....few people had 'A' grades, but those who did could go on and get a degree in the field with ease.

BTW when the grades actually 'counted' (as in, they would have had a definite impact on your enrollment chances), he simply gave everyone an 'A' who put in some effort.
He admitted that he won't **** with us for the sake of his own amusement, those who got 'A' grade were good to go, the rest shouldn't bother with the field as its not their cup of tea.

[Herra Tohtori]

I can feel your pain.


In my school (Helsinki University of Technology) we Physicists (students who study technological physics and mathematics) have kind of a running gag about Chemichists [sic]... As chemistry is after all nothing byt a hugely specified branch of physics, but many things in chemistry still use their own notations, own symbos and own.... well you name it.


I sometimes created controversies in class just for the sake of showing people that there *are* other ways of doing things. Lucky thing was that in high school we had excellent teachers in most subjects, so there wasn't too much need of such... I remember one occasion, though, in physics exam, where I deliberately used loose question notation to my advantage, posted two solidly based results using two different perspectives, and guess what - my work was not fully appreciated... It was about relativity, and to be more specific it asked how much time passes in earth when t amount of time passes in a space ship traveling at v (don't remember exact values), relative to Earth.


The question didn't specify the velocity vector of the ship in any other way than giving it a fixed value. I simply put in an example showing that from the perspective of linearly travelling space ship, time goes slower in Earth... But if space ship starts its journey from Earth, makes a biiig loop at velocity v and comes back to Earth, the space ship's time has passed less than Earth's time. 8)