Science & Mathematics - 7 December 2006

Solid urea, (NH2)2CO, burns to give CO2, N2, and liquid H2O. Its heat of combustion is -632.2 kJ/mol.

Balanced equation:
1(NH2)2CO(s) + 3/2O2(g) ---> 1CO2(g) +1 N2 (g) + 2H2O(l)

Calculate the heat generated per mole of H2O formed to 0.1 kJ.

Using this heat of combustion and the appropriate thermodynamic data, determine the heat of formation of urea to 0.1 kJ.

Make sure i have balanced right.. anything you can provide would really help/

2006-12-07 03:03:18 · 2 answers · asked by Anonymous in Chemistry

and who had the first one??

2006-12-07 03:02:46 · 7 answers · asked by Anonymous in Weather

(cont-) one flourine atom. The total # of carbon, hydrogen, and flourine atoms in in one molecule of flourtoluene is ANSWERS: a) 8 b) 12 c) 13 d) 15 e) 14

2006-12-07 03:00:33 · 1 answers · asked by BILLY D 1 in Chemistry

there are two groups of forces that are constanly changing earths appearance-constructive and destuctive forces.......i need to explain and give an example of each--serious answers only!!


thanks:)

2006-12-07 02:57:44 · 5 answers · asked by cowgirl642 2 in Earth Sciences & Geology

2006-12-07 02:57:31 · 1 answers · asked by Anonymous in Physics

Please help me && explain how you got this answer : /



When she rows with the current, Mindy can row 24 miles in 3 hours. Against the same current, Mindy can row only 2/3 of this distance in 4 hours. Find the rate of the current and Mindy’s rowing rate in still water. Assume that both rates are constant.



This problem is driving me crazy!!! Because they game me this:


Note: For a boat traveling in a stream, current has an affect similar to that of wind on an aircraft. A boat traveling upstream is traveling against the current. A boat traveling downstream is traveling with the current.


And that so called “hint” is frustrating because all it was was common sense.


So I discovered this:


Downstream ….Speed = rowing rate + current

Upstream….Speed = rowing rate - current

So rate x time = distance
(r+c) ....3 ....24
(r-c) ....4 ....2/3(24)

Now please help me figure out the rest. This problem is giving me a headache

2006-12-07 02:56:00 · 4 answers · asked by xolifes2sh0rtox 1 in Mathematics

exact distance please... in kilometers..

2006-12-07 02:55:34 · 1 answers · asked by Martin C 1 in Geography

a) 1.08 x 10(24)atoms b) 6.02 x 10(23)mol c) 6.02 x 10(24)mol d)1.82 x 10(23) atoms e) 6.02 x 10(23) atoms

2006-12-07 02:54:04 · 3 answers · asked by BILLY D 1 in Chemistry

just wondering if it would react the same as pseudo or just ephedrine

2006-12-07 02:50:41 · 4 answers · asked by sleep_problem 1 in Chemistry

I am considering developing a commercial use electrical product for sale within the EU and need to know how to self certify the CE mark.

Independant testing is very expensive and I do not believe it is necessary.

What guidlines do I need to follow to meet the requirements?

2006-12-07 02:49:50 · 4 answers · asked by Anonymous in Engineering

2006-12-07 02:49:34 · 6 answers · asked by starreyes2000_2000 1 in Chemistry

I want to communicate with Nevada or any other state without pushing power. I want to be able to prove to my fellow CBers that a cb radio can go to distance barefooted or should I say " Plain & simple"; Is it possible from Philadelphia?

2006-12-07 02:49:33 · 4 answers · asked by ltnscorpionking 2 in Engineering

some say it is a volcanic mountain in hawaii

2006-12-07 02:48:19 · 22 answers · asked by hellboy 2 in Earth Sciences & Geology

2006-12-07 02:47:55 · 5 answers · asked by Germstorm 2 in Physics

The Case for a Creator by Lee Strobel student edition
The Quantum theory states a space vacuum sometimes spits out objects for a brief amount of time then it is destroyed. The Kalam cosmological argument states these three things: every thing that begins to exist has a cause, the universe began to exist, and the universe has a cause. Experiences suggest that the first part of the Kalam argument is true. A research professor William Lane said, “The subatomic particles the article talks about are called ‘virtual particles.’ They are theoretical entities, and it is not even clear that they actually exist as opposed to being merely theoretical constructs.” Still we have to answer where the quantum vacuums came from. It appears step one of the Kalam held up. Early Christian Scientist used mathematical reasoning to show an infinite past is impossible. Imagine you have an infinite number of marbles and you gave me an infinite number of marbles. This would leave you with zero marbles. Infinity minus infinity equals zero. Or you only gave me the odd-numbered marbles. This would give both of us infinity. Infinity minus infinity equals infinity. Or you could give me all the marbles numbered four and higher leaving you with three. Infinity minus infinity equals three. An infinite number of things lead to contradictory results. Because in the first case infinity minus infinity equals zero, in the second case infinity minus infinity equals infinity, and in the last case infinity minus infinity equals three. Infinity was always subtracted from infinity but each time a different answer came up. The logical conclusion is that science confirms what the Bible says a Creator brought the universe into being. There can’t be a scientific explanation of the first state of the universe. In 1990 a biologist named Tim Berra stated if you compare a 1953 and 1954 Corvette side by side it is becomes obvious there has been descent with modification. Unknowingly he opened the door for the possibility for Intelligent Designer rather than undirected evolution. Henry Gee said “To take a line of fossils and claim that they represent a lineage is not a scientific hypothesis that can be tested, but an assertion that carries the same validity as a bedtime story – amusing, perhaps even instructive, but not scientific.” Jonathan Wells said, “I believe science is pointing strongly toward design. To me, as a scientist, the development of an embryo cries out ‘Design!’ The Cambrian explosion – the sudden appearance of complex life, with no evidence of ancestors – is more consistent with design than evolution. Similarity across species, in my opinion, is more compatible with design. The origin of life certainly cries out for a Designer. None of these things make as much sense from an evolution perspective as they do from a design perspective.” Wells also said “When you analyze all of the most current evidence from cosmology, physics, astronomy, biology, and so forth – well, I think you’ll discover that the positive case for an Intelligent Designer becomes absolutely compelling.”

2006-12-07 02:47:04 · 11 answers · asked by tribes777 1 in Physics

Just wondering.

Thanks.

2006-12-07 02:44:40 · 4 answers · asked by Anonymous in Engineering

chemistry mechanism of a person with xeroderma pigmentosum,strctures,and all about it.

2006-12-07 02:44:33 · 2 answers · asked by Anonymous in Chemistry

scientific method
data
graph

2006-12-07 02:44:26 · 1 answers · asked by Anonymous in Engineering

The Case for a Creator by Lee Strobel student edition
The Quantum theory states a space vacuum sometimes spits out objects for a brief amount of time then it is destroyed. The Kalam cosmological argument states these three things: every thing that begins to exist has a cause, the universe began to exist, and the universe has a cause. Experiences suggest that the first part of the Kalam argument is true. A research professor William Lane said, “The subatomic particles the article talks about are called ‘virtual particles.’ They are theoretical entities, and it is not even clear that they actually exist as opposed to being merely theoretical constructs.” Still we have to answer where the quantum vacuums came from. It appears step one of the Kalam held up. Early Christian Scientist used mathematical reasoning to show an infinite past is impossible. Imagine you have an infinite number of marbles and you gave me an infinite number of marbles. This would leave you with zero marbles.

2006-12-07 02:42:57 · 6 answers · asked by tribes777 1 in Physics

I know this effect is described as the difference in temperature that occurs in diffusive mixing of 2 non-interactive gases (for example hydrogen and nitrogen).
I have found articles about that, but they are too complicated for a person who is not an expert in physics.
I just need examples on how this effect can be applied, and a (simple) formula which tells me how to calculate this effect in mixing gases.

2006-12-07 02:42:36 · 1 answers · asked by valentina13 4 in Other - Science

If a virus spreads from 100 computers to 1,000,000 in 120 minutes and the equation is A(base of t)=A(base 0)e^kt , an original virus in 500 computers in 360 minutes?

2006-12-07 02:40:29 · 5 answers · asked by defman88 1 in Mathematics

2006-12-07 02:38:23 · 4 answers · asked by Anonymous in Astronomy & Space

i don't know whether its inertia or centrifugal force, i think inertia

2006-12-07 02:37:01 · 7 answers · asked by Anonymous in Astronomy & Space

2006-12-07 02:36:43 · 3 answers · asked by kc 1 in Biology

*links
*pictures

2006-12-07 02:36:07 · 2 answers · asked by FLACA 1 in Biology

Uses of X-ray diffraction technique

2006-12-07 02:35:12 · 2 answers · asked by tajnina k 1 in Chemistry

30 degrees in one place doesn't always feel like 30 degrees somewhere else, so it's not really a measure of how hot or cold a place is.

I know that with a drop in pressure, the temperature will drop, but does that mean temperature is essentially a measurement of pressure?

Thanks.

2006-12-07 02:34:22 · 5 answers · asked by Anonymous in Weather

2006-12-07 02:33:45 · 3 answers · asked by Michele 3 in Mathematics

2006-12-07 02:33:24 · 1 answers · asked by Leslie 2 in Physics

I know that's like asking how long a piece of string is. But there must be a typical or average figure per square metre of panel or something! I'm in the UK (same latitude as London).

2006-12-07 02:32:54 · 8 answers · asked by Geoff M 5 in Weather