Science & Mathematics - 31 January 2007

2007-01-31 05:44:28 · 11 answers · asked by alona p 1 in Mathematics

2007-01-31 05:44:24 · 8 answers · asked by dragonwolf017 1 in Astronomy & Space

2007-01-31 05:44:00 · 1 answers · asked by goring 6 in Astronomy & Space

Calcium chloride is used to melt ice or to keep it from forming on roads. This important compound can be produced by reacting calcium carbonate with hydrochloric acid. Two by-products are water and carbon dioxide. What would the balanced equation for the formation of calcium chloride by this reaction be?

2007-01-31 05:43:01 · 2 answers · asked by San Fran Kid 2 in Chemistry

A 0.250 L solution of 1.150 M hydrochloric acid is used to neutralize a 45.0 g sample of barium hydroxide in a coffe-cup calorimeter. Barium chloride, a chemical that is sometimes used to produce a bright green color in fireworks, is produced by the reaction. The temp. in the calorimeter was observed to rise from 20.0 C to 32.9 C during the course of the neutralization. Assume that the density of the hydrochloric acid solution is 1.00 g/mL and that the specific heat capacity of the system is the same as that for water, 4.18 J/(g*K). Assume that only water is available to absorb or release heat and that the reaction is at a constant pressure.
2HCl(aq)+Ba(OH)2(aq)-->BaCl2(aq)+2H2O(l)

1.What was the limiting reagent in the neutralization reaction? Provide support for your answer.

2. How many moles of excess reagent were left over?

3. If 27.3g of barium chloride were obtained after the neutralization was complete, what was the percent yield?

2007-01-31 05:42:15 · 1 answers · asked by Tracey Lee ♥ 2 in Chemistry

2007-01-31 05:39:42 · 6 answers · asked by kyle w 2 in Weather

2007-01-31 05:37:45 · 3 answers · asked by Jen ... 2 in Mathematics

In Geometric terms, you have rays and lines. A line can be said to start at a given point and continue left and right forever. A Ray however starts at one point and continues 1 direction forever. So which is longer? A Ray or a Line? Give a good argument for your interpretation. How about a circle? What is the end of a circle? Can a Ray of sunshine, become a segment of Sunshine? Can you argue both yes and no?

2007-01-31 05:36:08 · 6 answers · asked by sol 1 in Mathematics

2007-01-31 05:34:55 · 2 answers · asked by Anonymous in Physics

2007-01-31 05:34:49 · 9 answers · asked by maryrelaxing 2 in Astronomy & Space

1.) What evidence indicates that many quasars existed long ago??
2.) Why do astronomers hypothesize that there is a supermassive black hole at the center of the milky way?
3.) How do astronomers observe the spiral structure of our galaxy?

2007-01-31 05:33:11 · 9 answers · asked by Marie 2 in Astronomy & Space

Please Help with these. Ratio as fraction in simplest form.
8 pencils out of 12 pens 42 text books to 28 students
27 rooms to 48 windows 15 angel fish to 75 fish

2007-01-31 05:32:38 · 2 answers · asked by dreamer 1 in Mathematics

please help me i am doing a case study for school and need to write a explantion about my hypothesis : why should we pay ofr IVF? For once the internet is no good please help thankyu x

2007-01-31 05:31:45 · 10 answers · asked by Anonymous in Biology

2007-01-31 05:31:24 · 17 answers · asked by xtanyax 3 in Zoology

if anyone could help me out or give me some pointers that would be great! thanks!

2007-01-31 05:28:39 · 4 answers · asked by stinabofina 1 in Mathematics

Why do we have that "groove" under our noses, you know, right above our lips?

2007-01-31 05:27:07 · 2 answers · asked by Kilroy 4 in Biology

(Consider the directing effects of the ester and the first nitro group on the addition of the second nitro group).

2007-01-31 05:27:04 · 4 answers · asked by webogirl 2 in Chemistry

how does ionization energy change as one proceeds accross the periodic table and how does it change as you move donw the periodic table?

2007-01-31 05:26:56 · 3 answers · asked by cutie pie! 3 in Chemistry

2007-01-31 05:25:03 · 40 answers · asked by Anonymous in Astronomy & Space

if they are same why does it have so many names? and wht is thier importance?

2007-01-31 05:24:19 · 10 answers · asked by Anonymous in Geography

1- A flask contains 25.0 mL of diethyl ether weighing 17.84g.What's the density of ether?

2- What's the mass of 22.7mL sample of gasoline, whose density is 0.70g/cm^3?

3- The acidic constituent in vinegar is acetic acid. A 10.0mL sample of a certain vinegar contains 501mg of acetic acid.Whats the Mass of acetic acid expressed in micrograms?

4- A water molecule has 2 hydrogen atoms,each connected to an oxygen atom.The distance between any one hydrogen atom & the oxygen atom is 0.96 Angstroms.Whats the distance in millimeters?
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Is the formula for Mass: M= V x D?Because that's what my answers are based on.
1- Idk if I'm doing this right but I got:7.13 g/mL

2- I actually got 15.89 but using the correct amount of Significant Figures, I think I should end up with 15.

3- ? I'm trying to work it out now.
4- ? I'm trying to work this one out as well.

IDK if I'm doing these right.Can you please check what I'm doing & possibly explain the other ones to me.Thank You! = )

2007-01-31 05:21:54 · 3 answers · asked by Miss*Curious 5 in Chemistry

My grandfather asked me and I did not know the answer and I would like to be able to tell him how, since most of our conversations consist of wacky material such as this,lol. Thanks

2007-01-31 05:21:01 · 2 answers · asked by bigcontry17 1 in Zoology

2007-01-31 05:20:15 · 2 answers · asked by webogirl 2 in Chemistry

2007-01-31 05:19:07 · 9 answers · asked by Anonymous in Zoology

2007-01-31 05:19:00 · 6 answers · asked by Saddgal 2 in Earth Sciences & Geology

2007-01-31 05:18:56 · 5 answers · asked by Anonymous in Astronomy & Space

How are weathermen able to forecast the amount of precipitation for a storm?

For instance, the forecast for our area is for 1 inch of snow.

2007-01-31 05:17:47 · 11 answers · asked by mark my words 3 in Weather

Shouldnt fish dry up since they are surrounded by salt water? (Water wants to diffuse towards higher solute concentration. IE: salt) Is their body not permeable to water at all? Seems like the same thing should happen to them that happens to a slug.

What about when they drink the salt water? Wouldnt their cells dry up because the water in them would diffuse out of the cell (towards the higher salt concentration outside of the cell) Again, this is what happens to us when we drink salt water. Why doesnt it happen to fish? (Unless maybe they dont drink but get their water from eating?)

Thanks.

2007-01-31 05:16:54 · 4 answers · asked by James 1 in Biology

2007-01-31 05:15:54 · 10 answers · asked by Diggler AKA The Cab Driver 1 in Astronomy & Space

2007-01-31 05:14:38 · 20 answers · asked by stev k 1 in Mathematics