Science & Mathematics - 28 September 2006

Explain the following observations:

1. Barium chloride is added to potassium chromate(K2CrO4). Yellow ppt. formed.
(this mixture is separated into 3 test tubes for part 2 - 4)

2. 6M HCl is added to the mixture above, the ppt dissolves to form a yellow solution.

3. 3M H2SO4 is added to the mixture, no visible change, ie the ppt does not dissolve.

4. 6M HNO3 added to the mixture, ppt dissolves to form a yellow solution.




I need to explain the observations in terms of the equilibrium equations, Le Chatelier's Principle, etc. Also, im not sure of whats going on in the tube, and why doesnt sulfuric acid dissolve the ppt while the other two acids can? Thanks for your help!

2006-09-28 03:18:05 · 3 answers · asked by Noel 4 in Chemistry

2006-09-28 03:16:37 · 14 answers · asked by troy_ati 1 in Astronomy & Space

2006-09-28 03:15:55 · 2 answers · asked by tristunt 1 in Medicine

What is intelligent design???

2006-09-28 03:15:03 · 15 answers · asked by Saffy-Ann 1 in Other - Science

Gerry Gundersen mixes different soultions with concentratations of 25%, 40%, and 50% to get 200 liters of a 32% soultion. If he uses twice as much of the 25% soluion as of the 40% solution, find how many liters of each kind he uses.

Please no answers of "do your own homework." If I exactly understood the question, I wouldn't be asking for help. Any help is apperciated. Thanks!

2006-09-28 03:12:46 · 8 answers · asked by Anonymous in Mathematics

in modern society

2006-09-28 03:11:10 · 2 answers · asked by Roger A 1 in Chemistry

Jack Reinholt, a car salesman, has a choice of two pay arrangements: a weekly salary of $200 plus 5% commission on sales, or a straight 15% commission. Find the amount of weekly sales for which Jack's earning are the same regardless of the pay arrangement.

Please no answers of "do your own homework." If I exactly understood the question, I wouldn't be asking for help. Any help is apperciated. Thanks!

2006-09-28 03:10:01 · 10 answers · asked by Anonymous in Mathematics

2006-09-28 03:07:14 · 14 answers · asked by Anonymous in Astronomy & Space

I just think it seems a little strange that we look at the countries like we do... America on the left, England in the middle, China & Australia etc on the right, when really the map could have an upside down iceland as the focus point for example!! I do understand that the North & South Poles have to be North and South obviously, but who says that North has to be upwards, when if your in space the north pole is still the north pole, it just might be on the left, the right or wherever?! So why do Globe's, maps etc illustrate it always on top?
Thanks!

2006-09-28 03:06:10 · 15 answers · asked by booleycat19 1 in Astronomy & Space

Anything distinguishable from a thing is also a thing.

2006-09-28 03:04:05 · 8 answers · asked by The Knowledge Server 1 in Other - Science

Given a sample of radioactives substance, if half the material takes 10 years to decay to a non radioactive material, what is the rate of decay?
Given 1 ton of material, how long until 0.1% remains?

2006-09-28 03:01:50 · 3 answers · asked by Anonymous in Mathematics

2006-09-28 02:58:36 · 5 answers · asked by Anonymous in Mathematics

industrial chemicals

2006-09-28 02:52:50 · 3 answers · asked by goya 1 in Other - Science

2006-09-28 02:48:01 · 5 answers · asked by gim 1 in Astronomy & Space

2006-09-28 02:47:42 · 14 answers · asked by Anonymous in Other - Science

My immediate thought was photosynthesis, but surely that only makes carbohydrates. Even though carbohydrates do give plants the energy to grow, i don't think thats the full answer. Does anyone know the name of the whole process or is there something else completely? I've searched everywhere trying to find an answer!

2006-09-28 02:46:51 · 6 answers · asked by Anonymous in Astronomy & Space

2006-09-28 02:44:03 · 2 answers · asked by gulfarazahmed 1 in Physics

2006-09-28 02:41:05 · 6 answers · asked by Anonymous in Chemistry

why does water not form in a room for example

2006-09-28 02:40:38 · 9 answers · asked by Gerry 1 in Chemistry

2006-09-28 02:38:55 · 7 answers · asked by Anonymous in Chemistry

If a an integer, prove that a^2 is not congruent to 2 modulo 4 or to 3 modulo 4.

also I need help with this proof:

prove that every odd integer is congruent to 1 modulo 4 or to 3 modulo 4.

2006-09-28 02:38:47 · 4 answers · asked by Anonymous in Mathematics

As electro megnet produse flux when current flows thrugh windings.
But permenent megnet produse flux witout carring cureent as electromegnet. Therfore as fluxe is their in permenent magnet ,
there must be a indused current in it, (IF YES THEN I HAVE ONE EXPIRIMENTAL SETUP FOR FINDING THE CURRENT IN PERMENENT MAGNET ),(SEND ME ANSWERS ON :- nan1ban@yahoo.com)

2006-09-28 02:35:28 · 3 answers · asked by nan1ban 1 in Engineering

2006-09-28 02:31:48 · 8 answers · asked by spannerintheworks 1 in Mathematics

2006-09-28 02:31:26 · 4 answers · asked by Arun s 1 in Medicine

please help me

2006-09-28 02:19:14 · 4 answers · asked by flaca_cool_000 1 in Chemistry

2006-09-28 02:18:39 · 9 answers · asked by joeq1987 2 in Biology

please help me

2006-09-28 02:18:02 · 4 answers · asked by flaca_cool_000 1 in Chemistry

X(w) is the fourier transform of x(t). in time domain x(t) is a sinc function.

2006-09-28 02:16:56 · 1 answers · asked by sandeepkumar s 1 in Engineering

2006-09-28 02:13:09 · 15 answers · asked by Anonymous in Astronomy & Space

2006-09-28 02:07:59 · 14 answers · asked by dconstruct6 1 in Biology