Chemistry - November 2007

In chemistry, what is different about the different colors of light (on a light spectrum). How are each color characterized...like, according to elements, or atom emission of light, I don't know. Where can I find any information, I couldn't find any on searchengines!

2007-11-06 02:23:06 · 4 answers · asked by Christina 3

Dear Yahoo Answers,

I need some help with the following Question.

Ammonium carbonate decomposes according to the equation below;

(NH^4)^2CO^3 = CO^2 + H^2O + 2NH^3

If 32 grams of (NH^4)^2CO^3 decomposes calculate;
Atomic weights to use: N = 14, H = 1.0, C = 12, O = 16
a. the mass of NH^3 gas produced

b. the volume of CO^2 produced if measured at STP?



Any contibution will be appreciated.

Thankyou

2007-11-06 01:29:44 · 1 answers · asked by Anonymous

Determine mass of potassium nitrate that could be obtained as crystals if 100ml and 1 litre of saturated solution of potassium nitrate are allowed to cool from 80oC to 25oC:

2007-11-06 01:23:09 · 2 answers · asked by Anonymous

Hello Yahoo Answers,
I need some help on the following question.


Calcium Carbonate reacts with hydrochloric acid to release carbon dioxide according to the following equation.

CaCO^3 + 2HCl = CO^2 + H^2O + CaCl^2

Atomic weights Ca = 40.1 , C = 12.0, O = 16.0 , Cl = 35.5 , H = 1.0

a. If 12.5 grams of calcium carbonate are mixed with an excess of acid calculate the moles of CO^2 formed.

b. Calculate the volume of CO^2 ( at STP) produced from the 12.5 grams of Clacium Carbonate.

c.If the 12.5 grams of CaCO^3 had been mixed with a volume of HCl such that the number of moles of HCl was 0.2 moles, calculate the moles of CO^2 formed



Any contribution will be appreciated.

Thankyou

2007-11-06 01:14:55 · 3 answers · asked by Anonymous

1) Aluminum nitrate + sodium hydroxide ----> Aluminum hydroxide + sodium nitrate

2) Potassium chlorate -----> pottasium chloride+ oxygen

3) Phosphoric acid+magnesium hydroxide -----> magnesium phosphate + water

2007-11-06 01:06:11 · 1 answers · asked by Caramel 2

Hello Yahoo Answers,
I am having trouble with this Chemistry Question. Can I please have help?


N^2 + 3H^2 = 2NH^3 ALL substances are gaseous

Atomic weights N = 14, H = 1.0
a. How many moles of hydrogen gas would be required to react with 0.5 moles of nitrogen gas?

b. If 1.5 moles of nitrogen gas reacts with excess hydrogen calculate the mass of ammonia ( NH^3) produced.

c. If all gases were measured at the same temperature and pressure what would be the ratio of reacting volumes for
Nitrogen : Hydrogen : Ammonia
_______:_________:________





Any Contribution wil be apprciated.

Thankyou

2007-11-06 01:05:39 · 1 answers · asked by Anonymous

If possible, include an explanation.

2007-11-06 00:54:42 · 1 answers · asked by go_master 1

it's for our science project.. and i'm really an enviromentalist. so please do help=)

2007-11-06 00:37:31 · 2 answers · asked by natalie999 1

2007-11-06 00:16:50 · 2 answers · asked by Baby Gurl 1

Thanks! =D

2007-11-05 19:35:41 · 7 answers · asked by thirdigras 2

I think i got this one but I need to be sure. I have a chemlab tomorrow morning and im so lost...

2007-11-05 19:30:07 · 1 answers · asked by robbyack2000 2

Could someone please help with the following questions?

Gases usually possess negative volumes when the temperature falls below -273.15K.
I believe this is false?

A glass column is filled with mercury and inverted in a pool of mercury. The mercury column stabilized at a height of 735mm above the pool of mercury. What is the pressure at the atmosphere?
I think this would be 0.967 atm?

Gas A effuses three times as fast as gas B. Gas B has a MM = 120.g/mol. What is the Molar Mass of gas A?
I believe the answer is 13.3g/mol?

If gas A effuses at twice the rate of gas B, what is the ratio of the molar masses (B/A)?

How much faster will gas A (MM=44) effuse than gas B (MM=120.)?

A excess of phosphorus reacts with 4.0L of H2. How many liters of PH3 are produced at the same temperature and pressure as that of hydrogen? P4(s) + 6H2(g) --> 4PH3(g)

2007-11-05 16:54:51 · 1 answers · asked by Anonymous

Hello. I have been trying to solve this problem for so long but it's just too hard. I don't understand it.

Does anyone know how to find the 1st derivative and 2nd derivative of √2x*sinx (the square root of 2x times sinx. using the 1st and 2nd derivative tests.

I know that I have to use the product rule with the chain rule but it is not working and my teacher said my answer is wrong.

Any answers are appreciated, I just want to understand how to do it.

Thank you!

2007-11-05 16:46:49 · 2 answers · asked by nattym04 2

How would you prepare 60 mL of a 0.200M HNO3 from a stock solution of 4.00M HNO3?

2007-11-05 16:34:27 · 3 answers · asked by delixir_21 1

It is higher up on the activity series so would it for ZnO + H2?

2007-11-05 16:27:10 · 6 answers · asked by hishganish 2

MO(s) + CO2(g) MCO3(s)

A 2.80 g sample containing only MgO and CuO is placed in a 3.16 L container. The container is filled with CO2 to a pressure of 740. torr at 20.°C. After the reaction has gone to completion, the pressure inside the flask is 390. torr at 20.°C. What is the mass percent of MgO in the mixture? Assume that only the MgO reacts with CO2.

2007-11-05 16:15:05 · 1 answers · asked by mark 2

How would you expect sodium metal to react with sulfurous acid?

2007-11-05 15:36:33 · 1 answers · asked by Anonymous

2007-11-05 14:48:37 · 3 answers · asked by Anonymous

Would a sample of gas in a closed container in space (zero gravity) exert pressure on the sides of the container if the gas was kept at standard temperature and pressure? Explain.

2007-11-05 14:29:50 · 2 answers · asked by Anonymous

A glass column is filled with mercury and is inverted in a pool of mercury. The mercury column stabilizes at a height of 735 mm above the pool of mercury. What is the pressure of the atmosphere?

-1.03 atm
-0194 atm
-0.967 atm
-0.697 atm
-0.735 atm

2007-11-05 14:19:00 · 1 answers · asked by Anonymous

Problem from the back of my book. I have the answer but not sure how to work it.

A quantity of N2 gas originally held at 4.62 atm pressure in a 1.70-L container at 26°C is transferred to a 13.5-L container at 20.0°C. A quantity of O2 gas originally at 3.34 atm and 26.0°C in a 8.43-L container is transferred to this same container. What is the total pressure in the new container?

2007-11-05 14:15:03 · 1 answers · asked by Reviction 1

A 20.0-L stainless steel container was charged with 2.38 atm of hydrogen gas and 3.00 atm oxygen gas. A spark ignited the mixture, producing water. What is the pressure in the tank at 25 ºC? at 125 ºC

--My teacher said it has something to do with Avogadro's Law, but I have no idea how to even set up the problem since volume is constant??

Hints:
pt 1-- Since V and T are constant, Avogadro’s Law applies. Hydrogen is the limiting reactant.
pt 2--At this temperature the water is also a gas, and its pressure should be added to the pressure of remaining oxygen.

2007-11-05 14:07:23 · 3 answers · asked by nannybugsx83 1

2007-11-05 14:04:54 · 14 answers · asked by lanilaidan 1

A molecule that contains only carbon and hydrogen is composed of 74.83% carbon by mass.

a) What is the empirical formula?
b) How many hydrogen atoms are present in 25.8 g of this substance?

2007-11-05 13:58:02 · 3 answers · asked by bryon_barker 2

2007-11-05 13:33:59 · 2 answers · asked by Anonymous

Nitrogen and hydrogen gases react to form ammonia gas as follows:
N2(g) + 3H2(g) → 2NH3(g)
At a certain temperature and pressure, 4.07 L of N2 reacts with 12.2 L of H2. If all the N2 and H2 are consumed, what volume of NH3, at the same temperature and pressure, will be produced?

Ok so it gives me the liters and grams/moles and its not a limiting reaction. Do I use 273k at 1atm by chance?

And


The compound 1-iododecane is a nonvolatile liquid with a density of 1.20 g/mL. The density of mercury is 13.6 g/mL. What is the height of a barometer column based on 1-iododecane, when the atmospheric pressure is 769 torr?

I have worked several problems silimar to this but the question being in denisty screw me up. Do I some how convert the problem to mm Hg's since 760 mmhg=760 torr = 1 atm to find the height? I am guessing mm hg's.

I really apperciate your time guys. Answers has helped me so much in understanding in class.

2007-11-05 13:24:17 · 2 answers · asked by Reviction 1

ok i don't like to ask homework questions but i am somewhat stuck right now. I keep trying the problem but my answers are off. Here is the problem: Consider the dissolution of CaCl2:

CaCl2(s) ---> Ca^(2+) (aq) + 2Cl^(-1) (aq) deltaH = -81.5kJ

An 11.0g sample of CACl2 is dissolved in 125g of water, with both substances at 25.0°C. Calculate the final temperature of the solution assuming no heat lost to the surroundings and assuming the solution has a specific heat capacity of 4.18 J/(°C*g).
If you could help me understand how to do this problem then i think i can figure out the rest. Thanks in advance

2007-11-05 13:14:50 · 1 answers · asked by live in the moment 2

My specific question is...

The molecular weight of water is 18 amu. Therefore 18grams of water (=18mls H20) contains Avogadro's number of water molecules. What is the size (or dimensions) of a water molecule. I also need to clearly state my assumptions?!

How do i go about this problem?

Thanks for your help!

Jody

2007-11-05 13:07:37 · 4 answers · asked by Anonymous

ASAP please.

2007-11-05 13:01:35 · 12 answers · asked by hate mi kill mi nam mi raw !!! 2

2007-11-05 12:49:36 · 3 answers · asked by NoTrigger 2