Science & Mathematics - 7 October 2007

I don't understand hybridization really and i have to explain why nitrogen trifluoride and phosphoruos pentafluoride are stable molecules and how nitrogen pentafluoride does not exist.

Can someone explain how hybridization works by explaining them?

2007-10-07 07:29:48 · 1 answers · asked by senseless.student 1 in Chemistry

thus the sense of life has been interpreted as a lie by human understandings?

2007-10-07 07:29:05 · 7 answers · asked by ponzon 1 in Biology

I've had two telescopes in my life and both have served me quite well. A small refractor Celestron and a medium sized Meridian reflector. Nice scopes for the relative newcomer to astronomy.

Now after several years of using these two I need a bigger better one. Deep sky objects are my next port of call. Anybody got any ideas.

2007-10-07 07:28:22 · 7 answers · asked by Deadman81 2 in Astronomy & Space

hi...
im 20 and i have been suffering from chest pains since i was 8 years old. The pain usually only comes when im really stressed out. I worry over simple things so pretty much ive been getting these pains every day from when i was 8. These pains consist of sharp pains with a long tightness feel for an hour or two a time...
these last two days i have felt chest pain when i was under no stress but it only happened twice or three times so far..

should i be worried? cos i am...

thank you so much

2007-10-07 07:28:03 · 8 answers · asked by Danielle 3 in Medicine

2007-10-07 07:28:02 · 7 answers · asked by . 1 in Mathematics

2007-10-07 07:26:25 · 2 answers · asked by Mr. Problem 1 in Mathematics

Show that x,y,z are never three terms (not necessarily consecutive)of an A.P.

2007-10-07 07:24:55 · 5 answers · asked by Anonymous in Mathematics

use implicit differentiation to find an equation of the tangent line to the curve at the given point.

2007-10-07 07:24:22 · 2 answers · asked by yakov59 1 in Mathematics

A man decides to climb an office tower using the stairs. If the floors are 3.8 m apart, how much gravitational potential energy would the man have relative to the ground floor if he made it to the fifth floor?

The answer is 41 J, but how would you figure that out without knowing the mass?

2007-10-07 07:24:19 · 1 answers · asked by Anonymous in Physics

2007-10-07 07:23:09 · 5 answers · asked by . 1 in Mathematics

2007-10-07 07:21:39 · 3 answers · asked by . 1 in Mathematics

2007-10-07 07:20:26 · 11 answers · asked by strongbow 3 in Physics

3x+129+3x+27=180
thanks.

2007-10-07 07:19:59 · 7 answers · asked by Maggie 2 in Mathematics

Algebra help! the question states perform the indicated operation

2007-10-07 07:17:56 · 5 answers · asked by nabs l 1 in Mathematics

2007-10-07 07:15:34 · 9 answers · asked by . 1 in Mathematics

2007-10-07 07:12:00 · 7 answers · asked by cindy d 4 in Physics

Here are a couple of my ideas:
1. Scientific stuff, like landing near one of the poles.
2. Do something we've never done before, like land on the opposite side.
3. Land where we have landed before, to verify the stuff is really there and see what condition they're still in. Maybe the batteries on the moon buggy are still good!
4. Unfold a huge cloth or something that would be visible from Earth (at least with a telescope if not the naked eye).

2007-10-07 07:11:59 · 10 answers · asked by Anonymous in Astronomy & Space

2007-10-07 07:10:32 · 2 answers · asked by Andreu 2 in Biology

The ˇ5 in my equation means that the base is 5. I was thinking that the answer is ;

logˇ5 25√5
logˇ5 25 (Square root of 5 which is 2.236067978)
logˇ5 55.9016994
= 2.5

Does anyone else have any other ideas?

2007-10-07 07:09:47 · 4 answers · asked by Dylan Rose 1 in Mathematics

2007-10-07 07:04:51 · 3 answers · asked by Anonymous in Other - Science

Natural selection seems to make more sense to me. A white mouse living in a white landscape lives to breed and black ones die out. Evolution? Why take millions of years to change from an ape to a man? Bit slow to be a successful survival tool?

2007-10-07 07:02:41 · 11 answers · asked by Granny 1 in Biology

I am really stumped at this problem. I tried Googling it and Wikipeding it but no luck. Any help? Please include a reference.
**********************************************************************
The host of a party turned to a guest and said, "I have three daughters and I will tell you ow old they are. The product of their ages is 72. The sum of their ages are my house number. How old is each?"

The guest rushed to the door, looked at the house number, and informed the host that he needed more information. The host then added, "The oldest likes chocolate pudding." The guest then announced the ages of the three girls.

What are the ages of the three daughters? (Hint: All the ages are whole numbers)
**********************************************************************
HELP PLEASE??

2007-10-07 07:00:44 · 3 answers · asked by i LoVe To HuG<3 2 in Mathematics

Evaluate the limit:

Lim [(2x+1)^3 (x-3)] / (x^2 + 1)^2
x->infiniti

10 points to whoever solves it first (or is helpful to me in solving it)
PS: show work plz

2007-10-07 06:59:46 · 2 answers · asked by Anonymous in Mathematics

The van that you are using to move can hold 16 moving boxes. Each box can hold 60 pounds of books or 15 pounds of clothes.



Let b represent the no. of boxes filled w/ books. Write a function that represent the total weight w of boxes in the van

2007-10-07 06:58:20 · 1 answers · asked by Anonymous in Mathematics

a 60 watt filament lamp is operated from an alternating current supply. The RMs voltage of the supply is 240v at a frequency of 50 hz

(i) calculate the maximum current in the filament?

(ii) and show that the maximum power dissipated in the lamp is 120 w

Thanks!

2007-10-07 06:57:47 · 1 answers · asked by NKS 2 in Physics

simplify and write your answer to the positive exponent.

I think the answer is m^4, is this correct?

2007-10-07 06:57:37 · 1 answers · asked by Anonymous in Mathematics

2007-10-07 06:56:42 · 4 answers · asked by Anonymous in Physics

2007-10-07 06:55:47 · 15 answers · asked by NICOLA P 1 in Chemistry

I have stumbled across a web-site, proposing that possibly a "30 lunar-days" month was what we actually had sometime in history.

Does anyone know more about the subject?
I am intrigued. Is this worth my time?

Note, I am not uneducated but know NOTHING about astronomy.


http://www.direct.ca/trinity/360vs365.html

2007-10-07 06:54:23 · 5 answers · asked by Heinz H 5 in Astronomy & Space

1) what is 1mmol/l NADH in umol/ml and mgs/ml?
2) what is the importance of NADH metabolically? in quantitavtive analysis?
3) what is 0.005mmol/l Blue Dextran in mgs/ml? in nmol/l?
4) What is Blue Dextan used for in chromatography?
5)Broadly speaking, why is Hemoglobin a colored protein? why was this prepared in physiological salin(0.15mol/l NaCl) as diluent?
6) what is the molarity of a 2g/l glucose soln?
7) a winchester of commercial ammonia(NH3) specifies that it has 8.8g/l ammonia, how would you prepare 0.1 mol/l? what is this soln in mg/ml? umol/ml and %w/v?
8)what is the molecular mass of ethanol? how would you express 70%v/v ethanol in : mol/l, mmol/ml, %w/v and w/w?
[notes the speficifc gravity of ethanol is 0.789g/ml]
9)what is the molarity of a 0.1% w/w/ soln of cholesterol in ethanol? [Mol,mass of cholesterol=386Da]

i reli havnt got a clue here.
im so dead. brainy ppl pls help me!!

2007-10-07 06:52:30 · 3 answers · asked by Anonymous in Chemistry