Chemistry - November 2007

2007-11-05 09:16:28 · 2 answers · asked by Ashley V 2

2007-11-05 09:15:43 · 4 answers · asked by Ashley V 2

C?c?a?a?e?

2007-11-05 09:07:03 · 2 answers · asked by Anonymous

What changes in the oxidation number of oxygen must occur if it is to be an oxidizing agent? Explain.. thanks

2007-11-05 08:56:29 · 2 answers · asked by maybe714 1

In his explanation of the threshold frequency in the photoelectric effect, Einstein reasoned that the absorbed photon must have the minimum energy required to dislodge an electron from the metal surface. This energy is called the work function of that metal. What is the longest wavelength of radiation (in nm) that could cause the photoelectric effect in each of the following metals?
(a) Potassium, work function = 3.68 10-19 J
(b) Tungsten, work function = 7.16 10-19 J
(c) Silver, work function = 7.59 10-19 J

2007-11-05 08:55:32 · 2 answers · asked by Audre 1

I am just curious if all the elements in the periodic table can be combined into 1 object or creation or whatever you want to call it through whatever methods are available with today's scientific equipment. If so... any idea what that creation would be?

2007-11-05 08:55:20 · 2 answers · asked by nc_dixieman 2

How do I determine the oxidation states for atoms that contain more than two elements? For example:

-Na4Fe(OH)6
-XeOF4
-C6H12O6

I don't know how to figure out the individual oxidation states. Can anyone help me? Please?

2007-11-05 08:48:59 · 4 answers · asked by Anonymous

Find DH for the reaction in kJ/g.

2 C2H6(g) + 7 O2(g) ® 4 CO2(g) + 6 H2O (l)

is it -51.8,-1295,-1550, -1667, -3110

2007-11-05 08:28:37 · 1 answers · asked by Cassie G 1

Use the Rydberg equation to calculate the wavelength (in Å) of the photon absorbed when a hydrogen atom undergoes a transition from n = 1 to n = 3.
Å

2007-11-05 08:23:28 · 1 answers · asked by Anonymous

A mixture of 1.02 g of H2 and 2.21 g of He exerts a pressure of 0.480 atm. What is the partial pressure of each gas present in the mixture?
H2
atm
He
atm

2007-11-05 08:13:16 · 4 answers · asked by Heather L 1

How many mililiters is of NaOH was required to neutralize the acid?

2007-11-05 08:10:55 · 2 answers · asked by symia87 1

Identify the specific element that corresponds to each of the following electron configurations.
(a) [He]2s22p1

(b) [Ne]3s23p5

(c) [Kr] 5s1

(d) [Xe]6s1

2007-11-05 08:04:26 · 2 answers · asked by markusa_j 1

Chemistry AS homework, why is a nitrogen atom (0.075 atomic radius/nm) larger than an oxygen atom (0.073 atomic radius/nm)?
If you don't know what nm means don't even try! :)
Thanks

2007-11-05 07:54:31 · 5 answers · asked by AAAPokerJoker 2

35.04 mL of .237M I2 solution is required to titrate a sample containing As2O3. Calculate the mass of As2O3 (197.8 g/mol) in the sample.

As2O3 + 5(H2O) + 2I2 --> 2(H3AsO4) + 4HI

2007-11-05 07:45:10 · 4 answers · asked by Peter 2

31 P
15
How many protons in this atom?
How many neutrons in this atom?
How many electrons in this atom?
Please explain.

2007-11-05 07:38:28 · 2 answers · asked by Jen P 1

Sorry to keep bothering, I just seem to have a problem on each exercise *hides*

I got the more simple reactions, but when I'm thrown HCL and FCl2 I'm lost...
-------------------------------

Fe(s) + HCl(aq) ---> FeCl2 (aq) + H2 (g)

Balanced: Fe(s) + 2HCl(aq) ---> FeCl2 (aq) + H2 (g)

Oxidation numbers for each:
Fe = 0
2HCl === H=2(+1)=+2, Cl=2(-1)=-2
FeCl2 === Cl2 = 2(-1)=-2 therefore Fe= +2?
H2 = 2(1) === 2

If I'm right... only Fe is oxidized. Which is reduced? H stays 2 and Cl too.

Fe ---> Fe2+ - 2e-

2007-11-05 07:17:56 · 2 answers · asked by Pancha Pistolas 3

2007-11-05 07:17:13 · 2 answers · asked by Jen P 1

i am doing a science fair project on that question and i kinda need an idea of what im doing

2007-11-05 07:02:38 · 3 answers · asked by Anonymous

can someone tell me the heat of combustion for liquified hydrogen?

2007-11-05 06:05:35 · 2 answers · asked by thesilvernewt 2

Iron is extracted from iro oxide by removing oxygen.

A what name is given to reaction in which oxygen is removed from compound?

b Name an element that could e used to remove oxygen from iron oxide.

c write a word equation for the reaction that would take place in b




Titanium is used to make replacement hip joints.One reason wy titanium can be used in this way is that it resist corrosion.

A how is titanum protected from corrosion?

b Sugeest two other properties of titanium that make it suitable for this use.

2007-11-05 05:04:14 · 3 answers · asked by Anonymous

Water is a solvent in which of the following solutions?
A.Air
B.Liquid sterling silver
C.saline(salt)solution
D.Corn oil
_____________

which of the following statements about colloids is FALSE?
A. A colloid contains particles smaller than those in a suspension but larger than those in a solution.
B. A colloid does not settle out, because the partibles are contrantly tosssed about by the movement of the liquid particles.
C. A colloid is not a true solution.
D. A mixture of sand and water is an example of a colloid.
_______________
Which of the following statements about suspensions is TRUE?
A.A suspension contains particles smaller than those of a solution.
B. A suspension cannot be filterd
C. The large particles in a suspension eventually settle to the botom of the container.
D. A suspenstion is a true solution
______

2007-11-05 05:01:41 · 1 answers · asked by Anonymous

Hi everybody. I'm currently studying for a chem test and am stuck on this problem:

convert 1.76 X 10 to the negative 3 mol of cesium to grams.

The answer is 2.34 X 10 to the negative 1 grams.....but I can't figure out why.

Thanks so much in advance!

2007-11-05 03:49:07 · 5 answers · asked by Gym♥RAT♥ 3

a) Volatility of a liquid increases with increasing temperature

b) The equilibrium vapor pressure of a liquid results from evaporation exceeding condensation

c) The equilibrium vapor pressure of a liquid changes with temperature

d) The vapor pressure of a liquid at its normal boiling point is strongly affected by the type of molecules the liquid consists of

2007-11-05 03:46:08 · 8 answers · asked by unique_fantasy 1

What is the .......for Hydrogen, Cooper, Uranium, Mercury, Chlorine & Krypton:

Atomic number
Atomic Mass
# of electrons
# of protons
representative/
transition/
inner transition/
metal/nonmetal
Period #(n)
Group #
# of shells
Valence electrons
Halogen/noble gas/
Alkali Metals/
Alkaline earth metals/radioactive

2007-11-05 03:22:20 · 1 answers · asked by Anonymous

n = 1 to n = 4 for 1 mol H atoms.


J/mol

2007-11-05 03:20:06 · 1 answers · asked by Dumb B 1

which operate in the microwave region at 28.400 GHz (1 GHz = 109 Hz). Find the wavelength (in nm and angstroms) of this radiation.

2007-11-05 03:17:42 · 1 answers · asked by Bobby D 1

1. A 250cm^3 solution of NaOH was prepeared. 250cm^3 of this solution required 28.2cm^3 of 0.100 M (mol/dcm3) HCl for nuetralisation. Calculate what mass of NAOH was dissolved to make up the original 250cm^3 solution.

HCl + NaOH -> Nal + H2O

2. What volume of 5M (mol/dcm^3) HCl is required to nuetralise 20kg of CaCO3?

2 HCl + CaCO3 -> CaCl2 + H2O + CO2



im stuck would really appriciate some help thanks :)

2007-11-05 03:17:06 · 1 answers · asked by Anonymous

2007-11-05 03:16:52 · 1 answers · asked by Bobby D 1

You have equipment that operates at 61.0 percent efficiency for the reaction below.
Fe2O3(s) + 3CO(g) → 2Fe(s) + 3CO2(g)
If you need to produce 56.2 grams of iron in your equipment, how many grams of iron(III) oxide must you react with excess carbon monoxide?

I got 201g but it's not right. Any ideas. I really hate chemistry

2007-11-05 02:48:02 · 1 answers · asked by steelhead3686 3

My kid has a Science Project and this was the topic that we choose.

2007-11-05 02:41:55 · 3 answers · asked by jmowgli1 2