Chemistry - September 2007

2007-09-22 05:10:23 · 7 answers · asked by ChadBF 1

Why does it feel hotter when passing your finger over a flame, as opposed to through the middle?

2007-09-22 05:01:26 · 2 answers · asked by supernothingx 2

2007-09-22 04:54:45 · 6 answers · asked by nathalie b 1

2007-09-22 04:54:16 · 3 answers · asked by Curious 1

A stock solution containing Mn2+ ions was prepared by dissolving 1.748 g pure manganese metal in nitric acid and diluting to a final volume of 1.000 L. The following solutions were then prepared by dilution:
For solution A, 50.00 mL of stock solution was diluted to 1000.0 mL.
For solution B, 10.00 mL of solution A was diluted to 250.0 mL.
For solution C, 10.00 mL of solution B was diluted to 500.0 mL.

Calculate the concentrations of the stock solution and solutions A, B, and C.

2007-09-22 04:49:51 · 3 answers · asked by Anonymous

1) for seperation of a mixture by paper chromatography, what are the components of the green food coloring qualitatively and quantitatively?

2) what can be concluded about the identity of the components in the unknown mixture? Qualitatively and quantitabily

2007-09-22 04:47:20 · 1 answers · asked by Anonymous

Example: Observing Changes...

2007-09-22 04:26:32 · 2 answers · asked by synni ♪ 3

Automobile air bags are inflated by nitrogen gas. When a significant collision occurs, an electronic sensor triggers the decomposition of Sodium Azide to form nitrogen gas and sodium metal. THe nitrogen gas then inflates nylon bags, which protect the driver and front-seat passenger from impact with the dashboard and windshield. What volume of nitrogen gas measured at 1 atm and 27 degrees C is formed by the decomposition of 100g of Sodium Azide?

2NaN3 ---> 2Na + 3N2

Please help

2007-09-22 04:21:45 · 2 answers · asked by Gillbates 2

OK so for my lab I was collecting data for the properties of solutions in electrolytes and nonelectrolytes.
My group A solutions included CaCl^2, AlCl^3, and NaCl? Each had 0.05 M
Then I collected the conductivity for each using a probe and I got:
CaCl^2- 8210 conductivity
AlCl^3- 4993 conductivity
NaCl- 6502 conductivity

Now, why is it that the group A compounds, each having the same concentration (0.05 M) have such large differences as far as conductivity values? How could I write an equation of dissociation for each?

Please help!

2007-09-22 04:07:06 · 2 answers · asked by Anonymous

2007-09-22 03:20:19 · 4 answers · asked by Anonymous

2007-09-22 01:36:56 · 4 answers · asked by siva 1

is a strong acid, has a melting point of 148 degrees celsius, and has an aromatic ring?

2007-09-22 00:24:00 · 1 answers · asked by silver_beatle 2

I have an engine make of cast aluminum and a steel bolt stuck in it. I drilled the bolt out but i cannot remove the shell with the threads. Is there something i can use to cause the steel bolt to rust/dissolve but not attack the aluminum block?

2007-09-21 23:54:41 · 1 answers · asked by Yuval L 1

a) a type of weak bond involving the sharing of an electron with a hydrogen atom

If you could..kindly answer this link also. God bless!


http://answers.yahoo.com/question/index;_ylt=AsmCrsYCJjnl2UsBfzlIS2fsy6IX;_ylv=3?qid=20070920175026AAbGLYe

2007-09-21 23:30:20 · 5 answers · asked by Anonymous

What is the ph of 0.1 M HCN?

2007-09-21 23:13:18 · 2 answers · asked by Anonymous

in NaHCO3 combined with H2SO4

2007-09-21 22:52:36 · 1 answers · asked by Anonymous

Chemistry Questions: seperation of a mixture by paper chromatography
After you have done the things down below
To assemble and operate a paper chromatography apparatus.
To study the meaning and significance of Rf values.
To test various food colorings and to calculate their Rf values.
To comparer measured Rf values with standard Rf values.
To separate mixtures of food colorings into their components.



***what can be identified the components of mixture s by means of their Rf values? Rf= d1/d2?

I am stuck on the last qustion please help me with three to four sentences please this is urgent thank you for your cooperation

2007-09-21 22:09:51 · 1 answers · asked by Anonymous

Are molecular ions only formed by bombardment of electrons.
what are the similarities between radicals and ions.

2007-09-21 21:26:54 · 2 answers · asked by Maths Rocks 4

2007-09-21 20:48:21 · 1 answers · asked by monicakryzelle_fortes 4

Let C(t) be the concentration of drug in bloodstream. As the body eliminates the drug, C(t) decrease at the rate that is proportional to the amount of the drug that is present at the time. Thus dC/dt =-kC(t) where k is positive number. If C(0) is the concentration at time t=0, find the concentration at time t.

help me on this question please.....

2007-09-21 20:40:59 · 1 answers · asked by wow_wow1127 1

2007-09-21 20:01:06 · 4 answers · asked by Ron 2

Some people on TV news say that bottled water is the same as tap water. I usually drink bottled water that I buy from the supermarket in a bundle of 48.

Once a year my water company sends out a print out of all the chemicals/minerals that are in our city tap water suppy that include;
Calcium, Sulfate, Chlorodibromomethane, Methyl-tert-Butylether, Chloroform, Bromodichloromethane, Bromoform, Bromochloromethane, Fluoride, Nitrate, Lead, Copper, Sodium, Chlorine, Asbestos, Total trihalomethanes, Haloacetic Acids, Alpha Emitters, Combined Radium.

That was the list in my tap water. Isn't that bad for people? I don't want to drink that. Is that in my bottled water? Is bottled water any better or not? Who can tell me some expert information?

2007-09-21 19:38:30 · 6 answers · asked by Ron 2

lb > kg

Carrots are $0.79 per pound. What is the cost of 1.2 kg of carrots?

Please reveal steps in your results --thank you

b/c I tried: $0.79 lb x 1.2 kg/2.205 lb = 0.429 = $0.43

The result I have is wrong.

2007-09-21 19:32:34 · 2 answers · asked by xxxladyxxx 1

2007-09-21 19:12:48 · 8 answers · asked by endgame1915 3

2007-09-21 18:48:50 · 3 answers · asked by khorshid 1

What are the significant figures of the volume of a cube in cm. cubed with dimensions 12.6 to 12.6 to 12.6 mm. ?

Well, here is what i know. There are 3 significant figures in one of the dimensional values so you estimate to 3 significant figures. !2.6 mm. = 1.26 cm. ; 1.26^3=2.000376 ; the volume then would be 2.00 cm., leaving the trailing zeros alone.

I don't know if i am right. Someone correct me if i am wrong. My teacher didn't teach me anything about this and she expects me to be a wiz at it at the end of the weekend.

2007-09-21 18:25:31 · 4 answers · asked by Anonymous

after making the methanol molecule with a 3D kit and ozidizing it by removing 2 "H" atoms (not from the -OH group) and replace with an oxygen.

#1) name the substance made??

after making 2 more identical molecules, react the -OH groups.

#2) name the bond formed?
#3) write the equation for this reaction

then build a methanol and ust the acid molecules we made before. once again react the PH groups and
#4)name the bond formed????
#5) write the equation for this reaction

2007-09-21 18:14:49 · 2 answers · asked by mani_ayat_3 1

after building the methane molecule with a 3D kit. we oxidize the methane by removing 2 "H" atoms and replacing with an oxygen.

#1) name the substance made explain its structure.

#2) if a hydrogen is removed from the original methane molecule and a CH3 group has been added. what substance has been made? and how does it differ from an aldehyde??

#3)add hydrogens to this molecule (break double bonds and add H). what type of molecule have you created?

2007-09-21 18:08:35 · 1 answers · asked by mani_ayat_3 1

Is it or not?

2007-09-21 18:02:43 · 2 answers · asked by Caramel 2

What would you observe if a precipitate forms when you mix two solutions? Like how do you know a precipitate has formed (characteristics?). Thanks.

2007-09-21 16:59:16 · 3 answers · asked by me 3