Science & Mathematics - 19 September 2007

2007-09-19 08:30:37 · 3 answers · asked by mitchell_a_ok 2 in Chemistry

The main reaction in Ph3COH and PhOMe to produce Ph3CPhOMe. This reaction fails in ethanol but proceeds in acetic acid. I don't understand why. I know that one is a reversible reaction and the other is irreversible. But why? any help is greatly appreciated.

2007-09-19 08:23:58 · 3 answers · asked by Anonymous in Chemistry

"Two locomotives approach each other on parallel tracks. Each has a speed of v = 70 km/h with respect to the ground. If they are initially d = 7.5 km apart, how long will it be before they reach each other?"

2007-09-19 08:19:39 · 3 answers · asked by Brooke B 1 in Physics

I know it has something to do with the sea, but what i dont know?

2007-09-19 08:15:53 · 13 answers · asked by JOANNE 2 in Earth Sciences & Geology

2007-09-19 08:13:14 · 9 answers · asked by starlightstarry 1 in Mathematics

No answers, please. I just need to see the steps involved.

1. How many grams of SO3 (g) would be contained in 15.5L at 175kPa and 35.0˚C?

2. Calculate the boiling point of a solution containing 4.6mol of AlCl3 in 800g of water. (Kb for water = 0.512˚C/m)

3. A 0.150M solution of vinegar, CH3COOH, is only partially ionized so that the [H+] = 2.31 x 10-3M.

What is the Ka for this acid.

4. How many equivalents are in 15.0g of H3PO4?

I can learn how, but I need to see how it's done. The teacher can try to explain it all she wants, but I need to see it in order to understand it.

2007-09-19 08:07:30 · 2 answers · asked by Anonymous in Chemistry

1)5x^2 + 5x + 11

2)4x^2 + 7x -2

2007-09-19 08:00:42 · 5 answers · asked by Anonymous in Mathematics

hey how do you solve this? You have to use substitution..

2007-09-19 08:00:33 · 5 answers · asked by Anonymous in Mathematics

2007-09-19 07:59:53 · 5 answers · asked by Anonymous in Biology

Ok... I am involved in running a mine which contains a bit of gold but a lot of silver.

Problem with the mine is that the ore contains millions of ounces of silver - but the silver particles are encapsulated in silica.

Due to the silica problem, current known mining techniques are only seeing 5% of the silver in the mine being recovered - with the rest lost during the silver extraction process.

HOW could more silver particles be more easily recovered from the silica???????

An imaginative solution would allow much more profitibility from mining operations - and hence fund the winning prize by itself.

This is serious. If your answer is accepted seriously by the board.. we will seek to contact you in the future (by either email or IM or by seeking you out via an open question directed to you), to either ask for more detail on paper, or, if your answer is accepted and implemented due to it being creatively great, to simply award you your winning payment in 2008.

2007-09-19 07:53:32 · 6 answers · asked by Narky 5 in Other - Science

Please tell me how to calculate the mean radius of a cylinder whose radius and height are known.

an example you can use to try this yourself is radius=10 height=20 and the mean radius is 11.32.

2007-09-19 07:53:25 · 2 answers · asked by Anonymous in Mathematics

gametes?

2007-09-19 07:51:43 · 2 answers · asked by truebluehuni 1 in Biology

please answer in a detailed answer! thx:-)

2007-09-19 07:50:29 · 6 answers · asked by laces01234567890 1 in Engineering

Is the ball going fastest when it leaves the pitcher's hand and slows down til it hits the catcher's glove, or is there a bell curve on the velocity?

2007-09-19 07:49:10 · 4 answers · asked by crocolyle10 3 in Physics

and how do we calculate k the force constant, and is k the same for the same spring?

2007-09-19 07:43:22 · 3 answers · asked by arabian_kisses08 2 in Physics

explain how sedimentary rocks are formed. Include the name of one specific type of sedimentary rock as an example.

2007-09-19 07:41:47 · 1 answers · asked by Lovely 3 in Earth Sciences & Geology

1)Sqrt of 56x^5y^6 over 2y^4


2)7sqrt sign3+sqrt sign 6
over
sqrt sign 6+sqrt sign 3

thanks for the help!

2007-09-19 07:40:25 · 1 answers · asked by Duckie 26 2 in Mathematics

2007-09-19 07:39:39 · 10 answers · asked by Andreea 2 in Astronomy & Space

Like where?

2007-09-19 07:38:08 · 9 answers · asked by Anonymous in Astronomy & Space

I've read on different sites how atmospheric conditions limit telescopes' maximal performance/magnification based on Rayleigh criterion.
In telescopes' manuals are given 2 resolutions based on both standards.
They are given in arc seconds.So my question is:
If I know the Dawes limit ot the other can I calculate the maximal magnification based on it?I have resolution based on aperture and magnification based on aperture but such a "max reasonable magnification" is no good to me because that "reasonable" is relative.I want magnification based on resolution(arc seconds).How to calculate?

2007-09-19 07:37:09 · 3 answers · asked by OK 1 in Astronomy & Space

Alfred Wegener was a pioneer in the early development of the theory of plate tectonics. Wegener describes his ideas as "Continental Drift." Summarize or describe Wegener's ideas.

2007-09-19 07:36:49 · 3 answers · asked by Lovely 3 in Earth Sciences & Geology

For the sake of easier repair on orbit?

2007-09-19 07:31:38 · 2 answers · asked by Anonymous in Astronomy & Space

So, as I was searching for Christian arguments for the age of the earth, I found this site. I even found a few questions I could not answer and was wondering if someone could help me out. Here it is: "Since 1836, observations of the sun indicate it is shrinking about five feet an hour. Studies show this has been true for at least 400 years. At this rate, 100,000 years ago the sun would be twice as large as it is today. Twenty million years ago the sun would have touched the earth."
Thanks

The arguments for radioactive dating or obviously ridiculous but here is the site URL: http://www.barr-family.com/godsword/old.htm

2007-09-19 07:31:00 · 15 answers · asked by Anonymous in Astronomy & Space

are these values qualitative or quantitative?

1. measurements on the richter scale
2. area code
3. grade in school (ex. 4th grade)

2007-09-19 07:28:57 · 8 answers · asked by Bob 2 in Mathematics

HI everyone, my sign is sagittarus. born Nov 24th. i just want to know my moon sign.

2007-09-19 07:27:41 · 7 answers · asked by Anonymous in Astronomy & Space

2007-09-19 07:26:45 · 4 answers · asked by xtraudinair 3 in Medicine

f(X) = (2X^2 + 18 + X ) / X

the critical point is the derivative at 0, which is (2X^ 2 - 18 ) / X^2 = 0.

multiply both side by X^2 and you have (2X^2 - 18) = 0
divide both side by 2 and you have (X^2 - 9 ) = 0
Factor and you have (X - 3) (X + 3) = 0
So X = 3 and X = -3

According to my text book, it says that -3 is not in the domain. But WHY?? using -3 for X in the original formula does not cause any undefined values. Why is -3 not in the domain? Please let me know.

2007-09-19 07:25:53 · 2 answers · asked by Thai T 1 in Mathematics

Who can convert 1.64m into Feet (that is how tall i am and i want to know in feet) ta x

2007-09-19 07:24:17 · 21 answers · asked by Anonymous in Mathematics

I know that you multiply the term by 2 but i dont know how to make that work for the nth term equation, I tried Ax^2 + Bx + c and it didnt work...so if anyone can help me i would appreciate it! Thanks!

2007-09-19 07:20:36 · 8 answers · asked by gigembabe09 1 in Mathematics

together?

2007-09-19 07:18:38 · 5 answers · asked by Terri L 2 in Biology