Chemistry - December 2007

What is atomic spectra?? it would be awesome if you incorporated energy levels, ground state, excited state, and EM waves in your answer. thank youuuuuuu

2007-12-05 10:52:02 · 1 answers · asked by Valery 2

ok now im really confused on how to do this one. Stiochemetry is very hard for me and i need to know how to do this question step by step please =) .....ok here it goes

Consider the following unbalanced equation
P4(s) + F2(g) -------> PF3(g)
How many grams of F2 are need to produce 120.g of PF3 if the reaction has 78.1% yield?

2007-12-05 10:50:23 · 4 answers · asked by cheman1223345 1

Please help me asap!!!!

2007-12-05 10:22:59 · 1 answers · asked by shufalo 1

for science

2007-12-05 09:55:35 · 1 answers · asked by alissa smith 1

i had the following problem in my chemistry book. the answer that i got was not the same as the answer from the book. perhaps somebody could explain it? the answer that i got was that it was a consumption and that the final pressure was 754.50 torr. apparently the answer was that it was a production and the final pressure was 826 torr.

here's the problem:

A student carried out a reaction using a bulb connected to an open-end mercury manometer on a day when the pressure was
746 torr. Before the reaction, the level of the mercury in both arms was at a height of 12.50 cm, measured by a meter stick placed
between the two arms of the U-shaped tube. After the reaction, the level in the arm connected to the bulb was at 8.50 cm. Did the
reaction produce or consume gases? What was the final pressure in the bulb (in torr)?

2007-12-05 09:40:29 · 1 answers · asked by Anonymous

2007-12-05 09:40:25 · 4 answers · asked by Anonymous

would silver (I) oxide be Ag2O?

2007-12-05 09:21:48 · 4 answers · asked by iloveyou! 1

true or false

2007-12-05 08:57:23 · 4 answers · asked by DeeDee 1

Vehicles which run on fuel cell technology are currently being developed. These vehicles are quiet and efficient and make use of two plentiful elements - hydrogen and oxygen.

Fuel cells generate energy to power the vehicle by combining hydrogen gas (H2) and oxygen gas (O2) to form water (H2O) as shown in the following chemical equation.
2 H2+O2 ==> 2 H2O

If a fuel cell-powered vehicle can hold a maximum of 5 kg of water (i.e., the product), what is the maximum total amount of hydrogen and oxygen gas that should be used as reactants?


So if anyone could help, it'd be much appreciated.
If you can make me understand it, when I can, I'll give you the 10 points.
:3

2007-12-05 08:56:17 · 4 answers · asked by Blackberries. 2

How many grams of phosphorus react with 55.2 L O2 at STP to form tetraphosphorus decaoxide?
P4(s) + 5O2(g) → P4O10(s)

2007-12-05 08:32:44 · 1 answers · asked by Anonymous

What is the mass of a 364.0 mL sample of ammonia gas at 10.6oC and 144.76 kPa?

2007-12-05 08:27:48 · 1 answers · asked by Anonymous

starting with the far left carbon as one.

CH2CCHCH3

What is the molecular shape of carbon 3?

1. Bipyramidal

2. Square Planar

3. Trigonal Pyramidal

4. Tetrahedral

5. Linear

6. Trigonal Planar

7. Angular

2007-12-05 08:19:52 · 1 answers · asked by pocketdictionary 1

a) The shape and function of a protein is determined by the sequence of amino acids along the chain

b) The sequence of amino acids that make up a protein are known as the tertiary structure of the protein

c) Although proteins are long and complex, they have a regular structure that results from hydrogen bondng

d) The primary structure of different protein molecules is created by hydrogen bonds between
an amine group on one molecule and a lone pair of electrons on an oxygen molecule in an adjacent protein

e) One type of tertiary structure found in proteins is α-helix

f) The structrure of a protein that results from only hydrogen bonding between the side
chains of the different amino acids is called the tertiary structure

2007-12-05 08:17:06 · 1 answers · asked by Anonymous

why is sugar a non-electrolyte?

2007-12-05 08:16:44 · 3 answers · asked by ~They call me MOMMY~ 6

can two objects at the same temperature have the same amount of heat?

2007-12-05 08:15:22 · 14 answers · asked by Grace K 1

i think i got it right, but im not sure... i got


1s^2
2s^2
1p^6
3s^2
2p^6
4s^2
3d^10
3p^6
5s^2
4d^10
4p^2


am i right??? if not where did i mess up??

2007-12-05 08:12:40 · 1 answers · asked by schs_gurrl 3

if some examples.

2007-12-05 08:11:15 · 3 answers · asked by zorgani1 1

This is the problem:
Describe an experiment using only hot and cold water that would allow you to verify that the heat capacity of your coffee cup calorimeter is about 10 J/C. Be Specific

2007-12-05 08:09:20 · 2 answers · asked by Anonymous

How will the equilibrium position of a gas-phase reaction be affected by changing the volume of the reaction vessel?

( i think the greater the volume, the less the concentration would be therefore the less the equilibrium position would be)

Are there reactions that will not have their equilibria shifted by a change in volume?
yes or no
Explain.

(I don't really know here so if you could explain it to me that'd be great)

2007-12-05 07:45:34 · 1 answers · asked by topback35 4

What will be the freezing point depression if 42.0 g of ibuprofen (C13H18O2) is dissolved in 975 g of naphthalene? Kf for naphthalene is 7.00˚C/m

What is the boiling point elevation of 200. g of water when 11.4 g of ammonia (NH3) is dissolved in it? The Kb of water is .52˚C/m.

When 2.04 g of a substance were dissolved in 7.84 g of solvent, the freezing point decreased by 3.5˚C. The Kf for the solvent is 2.8˚C/m. What is the molar mass of the substance?

A solution is prepared using 18.0 g of an unknown substance in 150.0 g water. The boiling point was elevated .34˚C from that of pure water. The Kb for water is .52˚C/m. Calculate the molar mass of that substance.

What mass of ethylene glycol (C2H6O2, molar mass 62.1 g/mol) must be added to 10.0 kg water to produce a solution that freezes at-10.0°C? Kf for water is 1.86C/m.

What is the molar mass of 10 g of an unknown substance that raises the boiling point of .250 kg of water .75˚C? The Kb for water is .52˚C/m.

2007-12-05 07:41:43 · 0 answers · asked by Anonymous

Calculate the freezing point of a solution that contains 8.921g of (NH2)2CO in 85.0g of water. (NH2)2CO does not ionize in water. (Kf for H2O is 1.86 C/m)

2007-12-05 07:32:35 · 2 answers · asked by cdavis337 2

how do i write the reaction equation?

and why does the light go out, i dont really understand can you help me.

2007-12-05 07:13:06 · 6 answers · asked by jen27 1

What volume of O2(g) collected at 27 degrees C and 746 torr, would be generated by decomposition of 125g of a 50% by mass hydrogen peroxide solution?

2007-12-05 07:04:30 · 1 answers · asked by HaiLeY 4

i hear them talking about it on the radio and would like to know so i can converse in this subject

2007-12-05 07:02:12 · 2 answers · asked by gonzalo p 1

I've written down CH3CH(OH)COOH but I dunno if it's right

Also, what can you see when a colourless solution containing silver ions is tested with a solution containing chloride ions.
And what observation (if any) can you see when excess of aqueous ammonia is added to the mixture above.

2007-12-05 06:56:56 · 3 answers · asked by Anonymous

2007-12-05 06:51:36 · 4 answers · asked by Simba 2

A 150.0 g sample of a metal at 75.0'C is added to 150.0g of H2O at 15'C. The temperature of the water rises to 18.3'C. Calculate the specific heat capacity of the metal, assuming that all the heat lost by the metal is gained by the water.

2007-12-05 06:43:35 · 6 answers · asked by Caramel 2

A 15.0 g sample of nickel metal is heated to 100.0'C and dropped into 55.0 g of water, initially at 23.0'C. Assuming that all the heat lost by the nickel is absorbed by the water, calculate the final temperature of the nickel and water (nickel (specific heat) is 0.444 J/g 'C)

2007-12-05 06:30:48 · 1 answers · asked by Caramel 2

i dont know how to writ eht formulas for any of thees. i dont understand the methods you are supposed to use. i am so confused!
sulfuric acid
ammonium suflide
iron (II) oxide
hydrosulfuric acid
nickel bromide
bromic acid
ammonium bisulfate
nitrogen dioxide
sodium phosphate
magnesium phosphate
nickel bicarbonate
zinc hydroxide
hydroiodic acid
aluminum phoshpate
silver chromate
magnesium sulfite
chromium (III) phosphide
cobalt (III) nitrate
mercury (I) sulfate
copper (II) nitrite
phosphorus trichloride
lead (IV) chloride
iron (III) oxide
silver (I) oxide
manganese (II) hydroxide
ammonium carbonate
antimony pentasulfide
mercury (II) nitride
lead (II) hydroxide
mercury (I) iodate
iron (III) sulfate
nickel (II) sulfate
zinc (II) iodide
iron (II) flouride
nickel (II) selenide
sodium bisulfate
copper (I) carbonate
mercury (I) sulfate
manganese (II) oxide
nickel (II) chloride
lead (II) acetate
pottasium antimonide
nitric acid
cadmium nitrate

2007-12-05 06:25:48 · 6 answers · asked by iloveyou! 1

In which of the following statements is the functional group correctly identifed for the given compound ?


a) CH3CH2CH2COH alcohol


b) H3CCOCH3 aldehyde


c) CH3COOCH2CH3 ketone


d) C6H5CN amine

there may be more than one correct answer

2007-12-05 06:20:48 · 3 answers · asked by Anonymous