PHYSICS, CHEM HELP NEEDED

[godfather93]

CAN SOMEONE PLEASE EXPLAIN WHY SOME TERMS ARE NEGLECTED WHEN SOME FORMULAS ARE DERIVED? ISN'T ACCURACY LOST IN DOIN SO?

[godfather93]

ANYONE? ASTAR?

[Saladin]

Stop writing in caps,

and the answer to ur q is that some quantities can be expressed in others.

So a complicated formula, will have many derived values.

[godfather93]

Stop writing in caps,

and the answer to ur q is that some quantities can be expressed in others.

So a complicated formula, will have many derived values.

thanks 4 replying but thats not the answer i am looking 4

[godfather93]

ALSO can someone tell me the diff By the way +-(plus on top of minus) and -+(minus on top of plus)?

[nid404]

the symbol ?, meaning "minus or plus", used alongside the plus-minus sign to show that a negative value is to be taken where the positive value is indicated by the plus-minus sign, and vice versa (as in (x ± 1) / (x ? 2), which means (x + 1) / (x - 2) and (x - 1) / (x + 2)).

Hope that helped

[godfather93]

thanks for that! i had the same logic in mind but somehow in formula derivations, it doesn't seem to work that way!

[nid404]

put up a sample...I'll check it out

[godfather93]

i'll put up the sample later.

Right now, I have a more important and tricky question --

Is chemistry as a subject a completely  theoretical subject???

U may think as to why i'm asking that but have u ever wondered, for example, why the number of electrons in the outermost shell is 8? I mean there is no clear cut evidence saying so, is there?

[nid404]

Yes there is and it's a lil difficult to explain....
Check http://www.knockhardy.org.uk/ppoints.htm - electronic configuration

[godfather93]

ok here's another question. We've all being studying electricity. But can u answer this simple question -

Before the discovery of electrons, how were the terminals of the battery marked as positive and negative?

[godfather93]

moreover, i would like to know that if u guyz have learnt the quantum theory, are we supposed to just memorize the postulates and rules or is there any background info given to u on how the scientists discovered it?

sorry that i have loads of questions!

[godfather93]

According to the atomic theory, atoms are moving all the time, but to different extents in solids, liquids and gases. if we accept the theory, the question is why can't we see the motion of atoms in a liquid i.e why does it seem to be standing still when all the molecules are constantly moving here and there?

[nid404]

ok here's another question. We've all being studying electricity. But can u answer this simple question -

Before the discovery of electrons, how were the terminals of the battery marked as positive and negative?

when were batteries invented??

[godfather93]

1800, by Allesandro volta