Chemistry - March 2007

2007-03-11 11:46:37 · 4 answers · asked by avalentin911 2

2007-03-11 11:44:07 · 2 answers · asked by Rob F 1

how do people know that when you twist a double bond it breaks? Can you see the atoms or bond? also how do they actually twist the atoms atoms?

also in some cis- or trans- organic compound one causes instant explosion. How does this happen and does it form

2007-03-11 11:40:36 · 1 answers · asked by Hzl 4

2007-03-11 11:39:52 · 2 answers · asked by atlien2008 1

A common method for preparing a precipitate is to mix solutions containing the component ions of the compound you want to be a precipitate. Consider the mixture of 0.1 Liters of 0.3 M calcium fluoride is mixed with 0.2 Liters of 0.06 sodium nitrate. Does a precipitate form and what is it?

I know that the CaF2 precipitates because its ion product is greater than the solubility product constant. I'm not sure about the sodium nitrate.

These are the answers I have to choose from.

a. Nothing will precipitate out
b. Yes, CaF2 will precipitate out
c. Yes, NaNO3 will precipitate out
d. At first both NaNO3 and CaF2 will precipitate out but due to the common ion effect, both will dissolve back into solution.
e. At first both NaNO3 and CaF2 will precipitate out.

2007-03-11 11:36:38 · 2 answers · asked by Ulna G 1

rate from 1-4. 1 being easiest 4 hardest. ranking from easiest to hardest(1-4).

-Chemical Kinetics
-Chemical equilibrium
-Acid-Base equilibira and solubility equilibria
-Electrochemistry

2007-03-11 11:36:00 · 1 answers · asked by avalentin911 2

2007-03-11 11:31:24 · 6 answers · asked by mike 1

Sodium chloride is purified for use as table salt by adding HCl to a saturated solution of NaCl (317 grams/Liter). When 25.5 mL of 7.85 M HCl is added to 0.1 Liter of saturated NaCl solution, how many grams of purified NaCl percipitate?

2007-03-11 11:28:41 · 1 answers · asked by Stephanie C 1

These two questions are really bugging me. Anyone have any ideas?

A 0.05 M solution of hydrogen sulfide (H2S) contains 0.15 M nickel chloride NiCl2, and 0.35 M mercury nitrate Hg(NO3)2. What pH is required to precipitate the maximum amount of HgS but none of the NiS?

Even before the industrial age, rainwater was discovered to be slightly acidic from dissolved CO2. What is the pH of a bottle of rainwater collected in 1863 if the solubility of CO2 in pure water is 88 mL CO2 gas in 100 mL H2O. The Ka1 of H2CO3 is equal to 4.5 x 10^-7. the volume percent of CO2 in air is 0.033%.

2007-03-11 11:24:19 · 3 answers · asked by Anonymous

Also, what are oxidation numbers? And one last thing, How do families relate to valence electrons? Thank you SO much!

2007-03-11 11:19:06 · 1 answers · asked by nobody's home. 2

Calculate [ OH - ] of a 0.200 M solution of Pyridine C5H5N Kb = 1.70e-9

2007-03-11 11:15:50 · 3 answers · asked by tiggerx313 1

Please give the values in KJ/mol. Thanks in advance.

2007-03-11 11:12:02 · 6 answers · asked by Anonymous

Also, how many have been discovered but need to be named? Please answer! Thank you!

2007-03-11 11:04:21 · 2 answers · asked by Anonymous

I'm assuming my calculations are correct and AgBr will precipitate first, but i'm not sure how to explain why? Or maybe i'm wrong :P

2007-03-11 10:57:58 · 2 answers · asked by NerdyAndrew 2

2007-03-11 10:54:20 · 3 answers · asked by Anonymous

2007-03-11 10:49:38 · 2 answers · asked by Anonymous

2007-03-11 10:35:31 · 27 answers · asked by ? 1

plants use CO2, and H2O in Photosynthisis to make glucose (C6 H12 O6). if a plant has 88 grams of CO2, and 64 grams of H2O determine the following:

limiting reactant


excess reagent and mass in excess


mass of glucose produced






this one realy stumped me, I got 89.318 grams of glucose produced, and i cant figure out which is the limiting reactant and excess reagent.

thanks to whoever answers

2007-03-11 10:34:20 · 3 answers · asked by daniel T 3

thankyou!!!!!!

2007-03-11 10:30:46 · 13 answers · asked by ? 1

i'm not very good at maths?

2007-03-11 10:23:00 · 14 answers · asked by ? 1

How do we get B2S3 as the answer. Specifically, trying to figure out how we get 2 and 3..Boron has 3 and Sulfur has 6 electrons in its valence shell.

2007-03-11 10:20:39 · 1 answers · asked by Toothie 2

deals with stoichiometry and conversions of grams to mols.

2007-03-11 10:16:05 · 1 answers · asked by Anonymous

Technetium-99m is an ideal radioisotope for scanning organs because it has a half-life of 6.0 hr and is a pure gamma emitter. Suppose that 440 Mg were prepared in the technetium generator this morning. How many milligrams would remain after the following intervals?
1. one half life
2. two half life

2007-03-11 10:06:11 · 4 answers · asked by orange_crush_05 6

1All Brønsted-Lowry bases contain the hydroxide ion, OH-.
True
False

2. A solution is prepared by adding 0.10 mol of potassium chloride, KCl, to 1.00 L of water. Which statement about the solution is correct?
The solution is basic.
The solution is neutral.
The solution is acidic.
One needs to know the temperature before any of the above predictions can be made.
The values for Ka and Kb for the species in solution must be known before a prediction can be made

plz show works on number 2 or any explainations, thank you

2007-03-11 10:00:24 · 5 answers · asked by jennifer 2

I'm not sure if I answer this correctly.

Alcohol: hydroxyl group

Aldehyde and Ketone: carbonyl group

2007-03-11 09:59:13 · 4 answers · asked by shortydidi03 2

1. Which one of the following will give a solution with a pH > 7, but is not an Arrhenius base in the strict sense?
CH3NH2
NaOH
CO2
Ca(OH)2
CH4

2. Which one of the following substances will give an aqueous solution of pH closest to 7?
KNO3
CO2
NH4I
NH3
CH3NH2

can you guys help me wiff this one. i appreciate that.

2007-03-11 09:57:49 · 3 answers · asked by phong pham 2

What is the solubility of Al(OH)3 (Ksp= 3*10-34) in a slightly basic solution with pH of 8.44, in M?

2007-03-11 09:55:13 · 1 answers · asked by Anonymous

Using:
K = 39.10
Cl = 35.45
Oxygen = 16.00

I'm a little lost--can anyone help me out and show me how they did it?

2007-03-11 09:53:47 · 1 answers · asked by Burnt Toast 1

An ion can be removed from an aqueous solu-
tion by
1. the formation of what is essentially a
nonelectrolyte.
2. All of these
3. formation of a precipitate.
4. the formation of a gas that escapes.

In the net ionic equation for the neutraliza-
tion reaction between hydro°uoric acid (HF)
and sodium hydroxide (NaOH), the HF is rep-
resented as
1. neither the molecule nor the separated
ions since it is a spectator in the reaction.
2. the molecule, HF.
3. either as molecule or the separated ions.
4. the separated ions, H+ and F¡.

What is the net ionic equation for the reaction
between aqueous solutions of Na3PO4 and
CuSO4?
1. 2 Na+ + SO2¡
4
! Na2SO4
2. 3 Cu2+ + 2PO3¡
4
! Cu3 (PO4)2
3. Cu2+ + PO3¡
4
! CuPO4
4. No reaction occurs since no precipitate is
formed.

2007-03-11 09:51:29 · 1 answers · asked by dojorno5 2

A solution is 36.95% hydrochloric acid by mass and has a density of 1.195 g/mL. Find its molarity and molality.

I found the molarity to be 12.11 mol HCl/ L . So now I just need the molality.

Molality = # moles of solute / kg of solvent

2007-03-11 09:50:21 · 1 answers · asked by captinhankey 2