Science & Mathematics - 14 December 2006

2006-12-14 01:15:22 · 3 answers · asked by Rajeev M 1 in Geography

2006-12-14 01:13:49 · 26 answers · asked by elbellasera 2 in Astronomy & Space

the question is:
MgO and NaF is iso-electronic.However,the lattice energy of MgO is almost four times that of NaF.This is because:
1.The charges on the ions in MgO are higher than the charges on the ions in NaF
2.The inter-ionic distance in MgO is shorter as compared with that in NaF
3.The hydration energy of the Mg2+ and O2- ion is more exothermic.

My teacher told me that the (1) ,(2) are true.but (3) is false.
I really dont get it why (2) is true,because at that time ,it is still an exam,so we only got a sheet of table periodic with us.And from it,i can just see that Na 's radius is larger than Mg,but O's radius is larger than F.
I dont know which one between MgO n NaF has shorter distance of interionic.
Can somebody tell me how to see that by just using table periodic or maybe some theory?
and also,I can't think why (3) is wrong..

2006-12-14 01:11:39 · 1 answers · asked by Anonymous in Chemistry

Global Warming is due to the rise in volcanic activity.
Pollution is just complicating it.
Mother Nature is getting ready to do some major
housecleaning of Her own. And we're going to be
in the way!

2006-12-14 01:10:44 · 5 answers · asked by Master_of_Psyche 2 in Earth Sciences & Geology

The web is full of web pages stating that Windmills in Ireland turn the wrong direction from every other Windmill in the world.
Three questions:
1) Is this true
2) Why should it matter which direction since helicopters in Russia turn a different way from the others but still fly..
3) if your Desk Fan was a Windmill, which direction would it turn?
(if onfused this is the opposite side of when you turn it on)

2006-12-14 01:09:05 · 5 answers · asked by Anonymous in Engineering

2006-12-14 01:03:58 · 2 answers · asked by RAY EMIL M 1 in Engineering

I am at present doing a project for a science fair. In the project I have to make a magnet levitate over a electrically charged flat copper track or road. Now I have all the stuff I need ecept it's not working. When I put a 12 volt charge through the copper track and when I went to check if it was magnetised it did not show any magnetic characteristics (by the way the if has to be a fairly strong magnet). Can anyone tell me what I might be doing wrong?

2006-12-14 01:01:55 · 2 answers · asked by mikerushe 1 in Physics

2006-12-14 01:01:03 · 7 answers · asked by sudheep k 1 in Chemistry

other than dry cobalt chloride test paper( blue to pink if water is present), what kind of paper(s) can test whether the sample contain water?

2006-12-14 01:00:05 · 6 answers · asked by Anonymous in Chemistry

A chemist has one soluton that is 25% salt and 75% water and another solution that is only 5% salt. How many milliliters of each should the chemist use to make 1600ml of a solution that is 15% salt?

Can anyone please help me figure out the above? Or go over the steps with me to figuring it out? Thanks a bunch in advance! =)

2006-12-14 00:59:27 · 8 answers · asked by Ryan 1 in Mathematics

Please provide the url also if possible..

2006-12-14 00:57:45 · 1 answers · asked by Red Falcon 1 in Engineering

Is water a good electrical conductor ?

2006-12-14 00:57:19 · 14 answers · asked by Anonymous in Chemistry

2006-12-14 00:54:54 · 9 answers · asked by David H 6 in Astronomy & Space

it is a 3phase 240volt system
would settle for single phase to destination
i figured 3/0 wire 15ft up the pole the 4/0 triplex to destination. thought i'd atleast get 100 amp.
been told it could be done without stepping up then back down with transformer.

2006-12-14 00:54:16 · 2 answers · asked by mouse 1 in Engineering

I thought that being known since 800 BC mustn't have been something in favour of their existence but still, are they still there?

If they are or would have been there, how would have they affected the daily life there?

Do they or did they fascinate the researchers and physicists?

Really a very broad question but yea.... I am curious.

2006-12-14 00:54:11 · 2 answers · asked by Abhyudaya 6 in Physics

Where can I find Msc. in Engineering Business management from a high ranked university and flexibility in schedule for a busy proffesional in Industry?

2006-12-14 00:46:51 · 3 answers · asked by Hamody 1 in Engineering

I am in the prosess of doing a science fair project and as part of that project I have to use a voltage amplifter. So can anyone tell me how I can make a volyage amplifier. And don't tell me "go and buy one" I need to make one myself.

2006-12-14 00:43:07 · 1 answers · asked by mikerushe 1 in Engineering

if scientist theroize on a black hole how would they know whats really in a black hole and what it is. they just make a similation on it can they?

2006-12-14 00:41:34 · 13 answers · asked by zai wei 2 in Astronomy & Space

there would be new rules. a ref, a robot fighting commite to supervise the match 3 5 min rounds and weight division

2006-12-14 00:38:17 · 4 answers · asked by Zach 1 in Astronomy & Space

as far as i heard the moon isnt round. its a different shape and shows us the same side of the moon if anyone knows tell me pls thank you

2006-12-14 00:37:21 · 8 answers · asked by zai wei 2 in Astronomy & Space

it is wrong to kill a human.so ask your self this why is it ok to kill inhumanly,eat and digest animals? i mean it wouldnt be so bad if the animals werent alive when they started to skin them,and ,cut them up!
this brings me to my next point,it wrong to were a fur coat!why should a poor animal be killed for you to look good?!?come on people! it just commen sence! theyre living too!they feel pain!they have feelings too!

2006-12-14 00:24:33 · 11 answers · asked by silvers_girl_1192 1 in Zoology

No, really... what do they do? Where do they fit in the food chain... Why...

2006-12-14 00:24:02 · 25 answers · asked by Anonymous in Zoology

has this been screened yet, or is it due to be screened in 2007?

2006-12-14 00:22:49 · 6 answers · asked by catweazle 5 in Biology

2006-12-14 00:22:48 · 7 answers · asked by neha p 1 in Astronomy & Space

2006-12-14 00:20:13 · 4 answers · asked by Tangie 1 in Astronomy & Space

It's for a science project.

2006-12-14 00:17:58 · 2 answers · asked by hippiegirl 2 in Earth Sciences & Geology

I live in Finland and the sun rises at 9:30am, sets at 3pm.

2006-12-14 00:15:29 · 3 answers · asked by gabnella 6 in Astronomy & Space

Can anyone tell me what does a high and a low z-score mean(if possible,in more detail please)? Can a z-score be as high as 30+ and as low as -10? If so, what does it mean? Thank you!

2006-12-14 00:13:27 · 4 answers · asked by the DoEr 3 in Mathematics

2006-12-14 00:11:59 · 6 answers · asked by Barnes 1 in Astronomy & Space

A wooden right circular cone of altitude h and radius r is to be sawed into 3 parts of equal volume. How far from the vertex must the cuts be made? The cuts must be parallel to the base.

2006-12-14 00:11:42 · 3 answers · asked by Anonymous in Mathematics