Chemistry - October 2007

Please help me.

2007-10-12 07:50:12 · 1 answers · asked by Anonymous

Single water molecules can dissociate into hydrogen and hydroxide ions by themselves TRUE OR FALSE

WHY??

I think that the answer is FALSE. It is the "by themselves" that is throwing me off!

2007-10-12 07:46:28 · 4 answers · asked by LJC 2

Would a reaction take place when the following substances are mixed together? (i would say no because I don't think Hg can displace Al..)

Hg (s) + AlBr3 (aq)

2007-10-12 07:14:18 · 2 answers · asked by Jada 1

2007-10-12 07:00:35 · 1 answers · asked by LJC 2

Does heating copper sulfate produce a chemical or physical change? Why?

Also, does heating sucrose (table sugar) produce a chemical or physical change? Why?

2007-10-12 06:03:34 · 3 answers · asked by chemmyhead 1

Calculate the percent ionization of nitrous acid in a solution that is 0.249 M in nitrous acid. The acid dissociation constant of nitrous acid is 4.5x 10to the negative 4?

2007-10-12 05:44:00 · 2 answers · asked by Anonymous

Which ones are primary pollutants and which ones are secondary....

Sulphur dioxide
Nitrogen Monoxide
Nitrogen Dioxide
Carbon monoxide
Carbon Dioxide
carbon (soot)

2007-10-12 05:26:17 · 1 answers · asked by Anonymous

When you have a barbecue you burn the fuel to produce the heat needed to cook your food. When you have finished you have used up some fuel. But you have not used up the atoms in the fuel-the atoms are still somewhere. They have been conserved.

Q1)
If you used charcoal as the fuel,what happens to the atoms in the charcoal??

2) If you have used a gas barbecue, the fuel is natural gas (methane or butane) What happens to the atoms in a fuel?

3) Explain why, from the point of view of air quality,it is better to "get rid" of garden rubbish by composting rather than burning???

2007-10-12 05:23:22 · 4 answers · asked by Anonymous

(a) Potassium hydroxide(aq) + hydriodic acid(aq)
(b) Ammonia(aq) + hydrochloric acid(aq)
*molecular
*total ionic
*net ionic
*spectator ions

2007-10-12 04:44:52 · 1 answers · asked by Anonymous

2007-10-12 03:55:03 · 2 answers · asked by GoVols87 1

I know that graphite is molecule that conducts electricity becuase it has free electrons. However, I found that there are only 7 electrons in every graphite's outermost shell . Everything in nature need 8 electrons in their outermost shell to be stable. Isn't it? Who can help me to explain it by the principle of valence shell. Thanks.

2007-10-12 01:31:41 · 1 answers · asked by Anonymous

2007-10-12 01:19:36 · 1 answers · asked by Anonymous

Please put the follow sets of atoms in lowest to highest ionization energy (each letter contains 3 elements put those in order)

a. Mg, Si,S
b. Mg,Ba,Ca
c. F,Cl,Br
d. Ba, Cu, Ne
e. P, He, Si

2007-10-11 22:44:00 · 1 answers · asked by Anonymous

Which of the following compounds present exceptions to the octet rule ?

a) NH4+

b) PCl3O

c) XeF6

d) ClO3-

e) BrF3

THERE CAN BE MORE THAN ONE ANSWER SELECTED

2007-10-11 19:08:22 · 2 answers · asked by jason g 1

I got this wrong on my Chemistry quiz, but it may be on the upcoming test. The answer is 3, but I answered 6 on the quiz. Why is it 3? I just went by the 1s2/ 2s2 2p6/ 3s2 3p6 I thought it was 6 because that is what the maximun in the p.
Ahhhhhhhhh-help please?

2007-10-11 19:02:05 · 6 answers · asked by Boo Radley 4

i know one is synthesis.. but the other one? and why?
(:

2007-10-11 18:15:58 · 6 answers · asked by frenchychiffon 2

this is an easy question , but i need to be 100% sure its right

what do you get for

C3H8S(g) + O2(g) ---->
and
C3H8H(g) + O2(g) ---->

2007-10-11 17:44:10 · 1 answers · asked by Anonymous

Calculate the change in free energy (KJ) for the reaction
NO(g) + O3(g) → NO2(g) + O2(g)
under the following conditions:
T = 298 K ΔGo = -198.0 kJ/mol
Pressure of NO = 2.00 x 10-5 atm
Pressure of O3 = 1.98 x 10-5 atm
Pressure of NO2 = 2.70 x 10-6 atm
Pressure of O2 = 2.25 x 10-2 atm
Note that the value given above for ΔGo may not agree exactly with the value calculated using the thermodynamic data in the appendix of the text. Use the above value in this calculation.

2007-10-11 17:19:34 · 1 answers · asked by moare 2

Show the change in enthalpy calculation for the formation of NO from N2 and O2 using the following info:

NO (g) + .5O2 (g) --> NO2 (g)

change in enthalpy = -13.5 kcal/mol NO



i am so confused can someone help me please? (just telling me HOW to do it is fine)
THANK YOUUU <3

2007-10-11 17:15:18 · 1 answers · asked by Anonymous

Calculate the change in free energy (KJ) for the reaction
NO(g) + O3(g) → NO2(g) + O2(g) under the following conditions T = 298 K ΔGo = -198.0 kJ/mol

Pressure of NO = 1.72 x 10-5 atm
Pressure of O3 = 1.58 x 10-5 atm

Pressure of NO2 = 2.90 x 10-6 atm
Pressure of O2 = 2.25 x 10-2 atm

2007-10-11 17:12:57 · 1 answers · asked by Craig M 1

please explain

2007-10-11 17:12:46 · 1 answers · asked by Kol 1

1) decreases
2) increases
3) remains the same

and why? Thanks :)

2007-10-11 16:56:17 · 1 answers · asked by Anonymous

A voltaic cell consists of an Mn/Mn2+ half-cell and a Pb/Pb2+ half-cell. Calculate [Pb2+] when [Mn2+] is 3.3 M and Ecell is 0.17 V.

2007-10-11 16:36:55 · 1 answers · asked by socr8711 2

Why do atoms bond in an ionic bond?
and why do they bond in a covalent bond?

2007-10-11 16:24:43 · 3 answers · asked by greenpink413 2

2007-10-11 16:19:35 · 2 answers · asked by ggmal8 2

2007-10-11 16:18:10 · 1 answers · asked by bama12blue 1

In the United States, alcohol is rated according to "proof" which is usually defined as twice the percent by volume of pure ethanol in solution, measured at 60*F. What is the molarity of ethanol in a "92 proof" solution of ethanol in water. The density of ethanol (C2H5OH, molar mass=46g/mole) is 0.80g/cm^3 at 60*F; the density of water (H2O, molar mass= 18g/mole) is 1.0 gm/cm^3 at 60*F(15.5*C) Please Explain

2007-10-11 16:13:05 · 2 answers · asked by da_prospect_2006 S 1

A mol of photon in the red visible region of the electromagnetic spectrum has an energy of 181 kj/mol

calculate the wavelength in nm of the photons


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I have a solution but i dont understand it. i guess im supposed to change kj/mol to j/photon, why? how?

2007-10-11 15:56:46 · 1 answers · asked by Anonymous

If I drop an eyedropper drop of ordinary unleaded petrol into a container of exactly 1 litre, once it evaporates, what will the concentration of petrol vapour be, measured in PPM.

2007-10-11 15:45:23 · 1 answers · asked by Anonymous

I know that salt is primarily composed of NaCl, but how does the sodium and the chlorine get there if not all acids have sodium and chlorine?

2007-10-11 15:40:15 · 4 answers · asked by Rice R 1