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Science & Mathematics - 10 December 2007

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Agriculture · Alternative · Astronomy & Space · Biology · Botany · Chemistry · Earth Sciences & Geology · Engineering · Geography · Mathematics · Medicine · Other - Science · Physics · Weather · Zoology

I understand that forming the P=O drives the Wittig reaction forward but I am unable to comprehend why it helps initially when there is an overlap of the HOMO and LUMO? Does it lower the energy gap between the HOMO and LUMO?

2007-12-10 12:21:03 · 2 answers · asked by pwrfid 2 in Chemistry

1. Write a balanced equation for each of the reactions performed. Include the physical state of each substance. Classify each of the reactions as direct combination, decomposition, single replacement or double replacement.

Burning Mg:
2Mg(s) +02(g) > 2MgO (s) (? Type of Reaction)

Mg and HCl
Mg(s) + 2HCl(aq) >MgCl2(aq) + H2(g) (Single Replacement?)

Heating Cu
2Cu(s) +O2(g) > 2CuO(s) (? type of reaction)

H2O2 and MnO2
MnO2(s) + H2O2(aq)+2H(aq) > Mn2(aq) + O2(g) +2H2O (? Decomposition)

2KI + Pb(NO3)2 >PbI2 + 2KNO3 (? type of reaction)

2. Limewater is an aqueous solution of Ca(OH)2. Speculate on the identity of the cloudy white precipitate that forms with CO2 gas. Write a chemical equation for this reaction that is consistent with your observations.

3. A positive test for hydrogen was the "pop" test. What chemical reaction was occuribng? Write a balanced equations representing this reaction.

2007-12-10 12:19:27 · 2 answers · asked by Joey G 2 in Chemistry

The volume of gas is 400.0 mL when the pressure is 1.00 atm. At the same temperature, what is the pressure at which the volume of the gas is 2.0 L?

2007-12-10 12:18:26 · 3 answers · asked by Hannah L 1 in Chemistry

Does anybody know exactly how big it could have been if it was a meteor? Ive seen hundreds of meteors in my life . None like this!

2007-12-10 12:17:05 · 6 answers · asked by Anonymous in Astronomy & Space

What factors cause relative humidity to change?

Why is dewpoint temperature a better indicator of atmospheric moisture?

If the weather forecaster at 10:00 PM states that "the relative humidity has increased to 85% from the 65% relative humidity measured at 6pm” discuss what this statement may mean. Hint: The air in the evening usually cools down.

Summarize the processes by which water changes from one state to another. Indicate whether heat energy is absorbed or released.
on a cold winter day, when the temperature is –10°C and the RH is 50 percent, what is the total amount of water vapor in the air (also called the saturation mixing ratio)?
determine the RH and Td if the dry-bulb thermometer reads 16°C and the wet-bulb thermometer reads 12°C. Next, determine what the RH and Td would be if the dry bulb reads 16°C and the wet-bulb thermometer reads 8°C.

write a statement relating temperature and the capacity of the air to hold moisture.

2007-12-10 12:15:57 · 1 answers · asked by its_all_about_lady_jay 1 in Weather

Which plane is faster, the Blackbird or the X-43?
I try to find out but for some reason some website saw that the x-43 hasn't been flown yet!

2007-12-10 12:15:33 · 5 answers · asked by Richard 3 in Astronomy & Space

2007-12-10 12:15:22 · 1 answers · asked by flawless 1 in Biology

When was the 1st time you saw an aura&did you know what it was?
Did you do anything to cause you to see them? Do you see them around everybody all the time? Do you see them around animals too? Why can't I see them? (Should I be like pd and say because I can't see them...I don't believe they exist?)

2007-12-10 12:09:58 · 12 answers · asked by Deenie 6 in Paranormal Phenomena

A rectangle is to be inscribed in a semicircle of radius 8, with one side lying on the diameter of the circle. What is the maximum possible area of the rectangle? will you please explain how to do this??

2007-12-10 12:08:42 · 4 answers · asked by hannah 1 in Mathematics

answer in g/cm3

2007-12-10 12:07:53 · 1 answers · asked by Anonymous in Physics

im doing a report on the three types of rocks and i dont know if its metamorphic or sedamenary.

2007-12-10 12:07:17 · 1 answers · asked by Anonymous in Botany

1. why is the speed limit of the universe EXACTLY the speed of light?

2. why cant we go faster than that?

3. Why does time slow down the faster you go?

4. Just in theory, if we could, what would it be like if we went faster than the speed of light?

2007-12-10 12:02:06 · 5 answers · asked by Anonymous in Astronomy & Space

who , what , where , when and why

size and color

2007-12-10 12:01:34 · 3 answers · asked by lauren 1 in Astronomy & Space

2007-12-10 12:00:48 · 8 answers · asked by Tiko 3 in Biology

just answer yes or no?

And why doesn't ours fight back with the same?

2007-12-10 11:59:29 · 4 answers · asked by LandOfMisty 5 in Earth Sciences & Geology

Identify and describe the three types of blood vessels in the human body. Your answer should explain the following :
- the differences in their size (width) and structures
-the difference in their main functions and direction of flow
-if they usually carry oxygen - rich and/or oygen- poor blood

Ethan if u answer this u are definatly the smartest person one EARTH!

2007-12-10 11:58:03 · 1 answers · asked by lalalalala 3 in Earth Sciences & Geology

My little sister's doingg a science project...
she's onlyy 8 years old... help us please! =]

2007-12-10 11:56:27 · 10 answers · asked by Brenda 2 in Chemistry

How do you balance: Sodium hydroxide reacts with phosphoric acid to produce trisodium phosphate and water?
Thanks

2007-12-10 11:56:15 · 4 answers · asked by mune_ga_arimasu_ka 2 in Chemistry

I'm doing a science experiment in which I expose a plant to different concentrations of Windex and I want to see how it affects the plant's pigmentation, growth, and flower production. And I live in California. I would approximately have about 1 1/2 months to do the experiment. Thanks!

2007-12-10 11:54:17 · 3 answers · asked by Desiree 2 in Botany

2007-12-10 11:53:48 · 2 answers · asked by Anonymous in Chemistry

this plant is in Northeast Pennsylvania

2007-12-10 11:53:00 · 7 answers · asked by tmmz1107 2 in Botany

A solid sample of magnesium carbonate is heated strongly. how many total moles of products would be produced from 2 moles of reactant(s)?

2007-12-10 11:52:15 · 3 answers · asked by confusedkid 3 in Chemistry

1. Rewrite the square root of cos^2 + sin ^2 +cot^2 in a nonradical form without using absoulte values for pi
2. Points on the terminal sides of angles play an important part in the design of arms for robots. Suppose a robot has a straight arm 18 in. long that can rotate about the origin in a coordinate plane. If the robot's hand is located at (18,0) and then rotates through an angle of 60 degrees, what is the new location of the hand....??? this one is really confusing me..

I tried these a few times already and need some help. It would be greatly appreciated :)

2007-12-10 11:51:40 · 1 answers · asked by Anonymous in Mathematics

Water is added to a sample of solid magnesium nitride. Is the resulting solution acidic, basic, or neither?

2007-12-10 11:50:58 · 1 answers · asked by confusedkid 3 in Chemistry

2007-12-10 11:49:22 · 3 answers · asked by Anonymous is my name...lol! 3 in Engineering

The short side of an isosceles triangle is 16cm long. Increasing each side length by 24cm doubles the perimeter. how long are the other sides of the original triangle? explain your reasoning.

2007-12-10 11:49:06 · 2 answers · asked by hudson p 1 in Mathematics

Since sulfur is associated with fire, I assumed that if it was injected into the body, one could burn up internally. But is that actually true?

2007-12-10 11:47:38 · 16 answers · asked by Anonymous in Chemistry

x/x+2 + 4/x-2

2007-12-10 11:47:19 · 7 answers · asked by Anonymous in Mathematics

Solve for the value of x.
PLEASE SHOW THE STEPS!!

4x^(2/3) - 5 = 20

2007-12-10 11:46:43 · 1 answers · asked by Anonymous in Mathematics

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