Chemistry - January 2007

hey guys if you can help me out ...... do you know any facts about these elements?

carbon hydrogen helium iron copper nickel and zinc

or you can give me a web to go to

thanks!!!

2007-01-19 15:59:43 · 7 answers · asked by thrive 3

...With the below equation taken into consideration:

ZnS (s) + 2 HCl (aq) → ZnCl2 (aq) + H2S (l)

Help is greatly appreciated!

2007-01-19 15:48:47 · 6 answers · asked by Random G 3

2007-01-19 15:35:22 · 2 answers · asked by sbs89 2

Explain how you got the answer.
--the formula of acetic acid and blah blah blah.
Yep, thanks.

2007-01-19 15:25:54 · 5 answers · asked by Anonymous

2007-01-19 15:19:41 · 5 answers · asked by Fruit Loopz 1

2007-01-19 15:13:59 · 4 answers · asked by rhazzellee 1

You are heating a quart of boiling water. After taking it off of the burner, you have the task of getting the water to the lowest temperature possible at the 15 minute mark. You MUST add 50 ml of ice water in order to do so (can't omit it).

Should you add the ice water immediately after taking the boiling water off of the burner, or wait add the ice water at the 14-minute mark? It is either or; no times in between. Or does it matter at all?

2007-01-19 14:54:28 · 8 answers · asked by Cantaloupe 2

Calcium carbonate was thremally decoimposed . The ensuing gas completely neutraliserd one litre of 0.1N solution of ammonia. Assuming complete decomposition calculate the mass of calcium carbonate decomposed.

2007-01-19 14:34:01 · 3 answers · asked by Anonymous

Can you please explain the following:
The addition or removal of a substance in solid or liquid state does not change the concentration of that substance. The reaction of conndensed phases takes place only at an exposed surface- and if the surface exposed is changes it is always exactly the same chnage in available area for both forward and reverse reaction collisions. The forward and reverse rates will change by exactly the same amount if they change at all, so equilibrium is not disturbed and no shift occurs.

2007-01-19 14:22:40 · 2 answers · asked by S 3

I just got this question off of my biology studyguide im not sure what my professor meant by it but i thought he meant the names of the orbits in an atom spdfghi???

2007-01-19 14:08:53 · 5 answers · asked by Anonymous

2007-01-19 13:59:36 · 3 answers · asked by winston 2

Thanks in advance for the help.

2007-01-19 13:21:51 · 3 answers · asked by Random G 3

Ok, so i did out this problem, but in the answer booklet, i have no idea where this number comes from.
So the problem asks:
HF<-->H+ + F-
a. 40 g HF and 2kg water, determine mass of each substance which is needed to make max quantity of .1 molal HF solution.
i figured this out to be 4 g (0.2 mol) HF and 2 kg water.
the next part asks:
Determine the molality of F- ions and the molality of HF molecules in the solution prepared as directed in part a.
what the book does is, it says that the molality of all dissolved particles is equal to the sum of the molalites of H+ ions, F- ions, and HF molecules.
mH+mF+mHF=0.108 <<<---Where does that number come from/?????
it then explains, per kg solvent, let x=mol HF dissociated=mol H+formed=mol F- formed
0.1 - x = mHF
x+x+(0.1-x)=0.108
x=0.008
Now what confuses me is where the 0.108 came from?!?!?!?
it says no where how it comes from or where they got it?
possible explanation please?

2007-01-19 13:12:48 · 2 answers · asked by Anonymous

i know it's increase, but does its volume increase or decrease? and an explanation why please.

what is the minimum number of calories needed to chance 40 grams of water at 100 C to steam at the same temperature and pressure? 1. 43200, 2. 21600, 3l540, 4.40.


A gas sample is at 10 C, if pressure remains constant, the volume will increase when the temperature is changed to. 1. 263 K, 2. 273 K, 3. 283 K, 4.293 K

2007-01-19 13:12:19 · 3 answers · asked by Celia 4

i've been learning about them but never get a chance to see a real one.

2007-01-19 13:07:28 · 7 answers · asked by Ha!! 2

If the principal quantum number of a shell is equal to 2, what types of orbitals will be present? Is it s and p, or just s? Also, if the principal quantum number of the outermost electron of an atom in the ground state is n=3, what is the total number of occupied principal energy levels contained in the atom? Is it 1, 2, 3, or 4?

2007-01-19 12:35:47 · 1 answers · asked by Anonymous

I know there's some smoke while it's burning. but when you blow them out and the wick is still glowing a little, lots and lots of smoke comes out. why is this? what's the difference between flame and glowing? and why does the glowing make so much more smoke?

2007-01-19 12:20:33 · 3 answers · asked by JizZ E. Jizzy 2

The initial temperature is 18 C.Find the final temperature.

2007-01-19 12:15:32 · 1 answers · asked by zizi m 1

2007-01-19 12:14:20 · 4 answers · asked by sailorzfire 1

The equation for the reaction described in the question is NH4Cl (s) --> NH3 (g) + HCl (g)

Any help is appreciated!

2007-01-19 12:11:18 · 2 answers · asked by Random G 3

expanding isothermally from the initial pressure of 5 atmosphers to the final pressure of 3 atmospheres ,at the temperature of 0 C?

2007-01-19 12:02:27 · 1 answers · asked by zizi m 1

2007-01-19 11:51:13 · 6 answers · asked by Baby~D R 1

make hypothesis about the effect of temperature on reaction rate.

2007-01-19 11:46:23 · 2 answers · asked by help ^_^ 1

What is the strangest stories you have heard about oxygen, actinium, and chromium. The first one to answer all three gets the best answer.

2007-01-19 11:30:52 · 2 answers · asked by Immortal Syther 1

I just want a quick confirmatin/explanation. Are positive ions called positive ions because they have more protons than electrons. And are negative ions called negative ions b/c they have more electrons than protons? And is this what allows current to flow? thanks

2007-01-19 11:01:49 · 5 answers · asked by Anonymous

2007-01-19 10:36:23 · 4 answers · asked by cmwestbrook2002 1

2007-01-19 10:35:51 · 8 answers · asked by Anonymous

I know of at least one method, diluting it and slowly pouring into the drain, but it can still stain and eat away metals in the pipes a bit. Is there something else I could use to possibly just "neutralize" it? I think an alkaline metal nitrate would work (Li;Na;K) or some other salt. That or maybe even just try to get the pH as neutral as possible.

2007-01-19 10:18:51 · 3 answers · asked by Francis X 1

How many moles of sodium are there in 2.5 moles of Na3PO4

2007-01-19 10:05:25 · 4 answers · asked by hey hey. i'm here to stay. 2

How does the "collision theory" relate to the rate of a chemical reaction?

2007-01-19 09:48:00 · 3 answers · asked by help ^_^ 1