Chemistry - May 2007

I wonder if there are some methods could remove impurity of NOx in ozone gas besides using oxygen as material.
And are there any sensitive methods to measure ozone in water???
Thanks alot

2007-05-04 03:06:59 · 2 answers · asked by hlliu827 1

I wonder if there are some methods could remove impurity of NOx in ozone gas besides using oxygen as material.
And are there any sensitive methods to measure ozone in water???
Thanks alot

2007-05-04 03:05:55 · 1 answers · asked by hlliu827 1

I thought salt was bonded by very electrostatic forces of attraction? How come it dissolves in water?

2007-05-04 02:53:12 · 3 answers · asked by Anonymous

what is the actual reaction, I know universal indicator is made up of a lot of indicators, but which one reacts to change the colour, what reaction takes place and why does the colour change. why doesn't it happen when Universal indicator is added to water?

2007-05-04 02:34:35 · 6 answers · asked by Andy C 1

2007-05-04 02:32:36 · 1 answers · asked by cpc26ca 1

2007-05-04 01:56:38 · 2 answers · asked by harriet w 1

amount of heat released when acetylene burns with oxygen, producing carbon dioxide and water. First, write a balanced equation for the combustion of acetylene in oxygen. Then, how many grams of acetylene are needed for the complete combustion of 784 grams of oxygen? How many carbon dioxide molecules are formed in this reaction? please explain

2007-05-03 21:06:45 · 4 answers · asked by Anonymous

which contains hydrochloric acid. The unbalanced equation for this reaction is CaCO3(s)+HCl(aq) ----> CaCl2(aq)+ H2O(l)+CO2(g). How many calcium carbonate tablets, each containing 500 mg of the active ingredient are required to react with 18.5 grams of stomach acid containing 49.5% HCl by mass? please explain

2007-05-03 20:47:27 · 2 answers · asked by Anonymous

a. NaCl ,
b. H2O,
c. NaOH,
d. C8H18 (octane)
e. none of them

Checked everywhere in my text but cant figure it out still, arghhh!! And if anyone knows the answer can you tell me why as i would love to know as this question has me beat, for now.

Thanks heaps guys

2007-05-03 19:29:41 · 4 answers · asked by Anonymous

Does anyone know the products of the following reactions?

CoCl2 + NH3 --> ?
Zn(NO3)2 + NH3 --> ?
CuSO4 + NH3 --> ?
Na2CO3 + NH3 --> ?
AgNO3 + NH3 --> ?
FeCl3 + NH3 --> ?
Ba(NO3)2 + NH3 --> ?

I know that a precipitate forms for each of the reactions, but i dont know what the chemical formula of the precipitates is.

Thanks

2007-05-03 18:47:34 · 2 answers · asked by bballl 2

predict the sign of Delta Ssys for each of the following processes. For each statement select P-Positive, or N-Negative.
A) 2NO2(g) -> N2O4(g)
B) H2S(g) + 1/2O2(g) -> 1/8S8(s) + H2O(g)
C) 2K(s) + F2(g) -> 2KF(s)
D) CaCO3(s) + 2HCl(aq) -> CaCl2(aq) + H2O(l) + CO2(g)
E) 2KClO3(s) -> 2KCl(s) + 3O2(g)

2007-05-03 18:34:15 · 2 answers · asked by socr8711 2

M1V1=M2V2 or M1/V1=M2/V2?

Now I know that the first one is the right one, but why? Why won't the second one work? It's a proportion problem, right?

2007-05-03 18:02:57 · 5 answers · asked by CIC 1

Give two examples of single replacement reactions in which a metal and a salt give rise to a new metal and a new salt?

2007-05-03 17:04:26 · 4 answers · asked by theoneandonly4251 2

polyurathane foam

2007-05-03 16:48:22 · 1 answers · asked by Jasmine J 1

2007-05-03 16:41:17 · 1 answers · asked by Anonymous

Please help me some school work am confuse about.

How much heat will be released when 6.44g of sulfur reacts with excess O2 according to the following equation?

2S + 3O2 ⇒ 2SO3 ΔH゜= -791.4kJ.

i was taught to solve it i need to do the following(not 100% sure if this is the right way to solve this)

6.44g x 1mol/32 x -791.4/2mol = the answer.

My question is. Is this the right way to solve it. and for the question if i replace the word "Released" to "absorbed" obviously　ΔH゜ would a positive number. if it's positive do I need a different way to solve it?

2007-05-03 16:40:06 · 3 answers · asked by kabujun 3

Plastic no way but.Help.

2007-05-03 16:32:49 · 7 answers · asked by Anonymous

2007-05-03 16:29:54 · 2 answers · asked by mike 1

Please explain how soup on a pan on a stove is heated by conduction and convection.... please?

2007-05-03 16:27:43 · 4 answers · asked by mscassieandra 1

The half-life of carbon-14 is 5730 years. The daughter is stable nitrogen-14. A sample contains 1/4 C-14 and 3/4 N-14. How old is the sample?

2007-05-03 16:26:10 · 1 answers · asked by thunderbomb90 3

2007-05-03 16:20:43 · 1 answers · asked by Meno 1

a) is an electrolyte
b) is volatile
c) is nonvolatile
d) is liquid at the boiling temperature of water

2007-05-03 16:18:21 · 1 answers · asked by Meno 1

Assume that equal masses of two nonvolatile solutes of different molar masses are dissolved in two identical water samples. How do the freezing-point depressions of the two resulting solutions compare?

a) the depression for the higher-molar-mass solute will be less
b) the depression for the higher-molar-mass solute will be greater
c) the two depressions will be equal
d)any of the above might be the case, depending on the particular solute

2007-05-03 16:15:46 · 4 answers · asked by Meno 1

a sample of a gas in a cylindrical chamber w/ a movable piston occupied a volume of 1.40 liters when the pressure ws 762 torr and the temp. was 26.9 deg C. The volume of the system was readhusted to 0.150L by moving the piston. What was the pressure on the surface of the piston, in atmospheres, by the gas if the temperature remained constant?

I keep getting this wrong, I think I'm missing something

2007-05-03 16:15:37 · 2 answers · asked by A 3

a) lower both vapor pressure and freezing point
b) lower neither vapor pressure nor freezing point
c) lower vapor pressure but not freezing point
d) lower freezing point but not vapor pressure

2007-05-03 16:09:55 · 3 answers · asked by Meno 1

How does the temperature range over which a solution remains liquid compare to the range over which the corresponding pure solvent remains liquid?

a) the solution's range is narrower
b) the solution's range is wider
c) the two ranges are equal
d) any of the above may be true depending on the solvent

2007-05-03 16:07:49 · 1 answers · asked by Meno 1

And what types of things do you do, also do you need to know alot of math?

2007-05-03 16:06:09 · 9 answers · asked by koko 4

2007-05-03 16:04:40 · 5 answers · asked by Manuel L 1

What volume would 11.2g of a gaseous compund occupy at STP if the molecular weight of the compund is 44.0g/mole and the substance behaves like an ideal gas?

2007-05-03 16:02:36 · 2 answers · asked by A 3

I have a homework question that asks:
Write the balanced formula unit equation for the reaction of nitrogen oxide with oxygen. What is the sum of the coefficients? The problem is that it doesn't provide the formula for Nitrogen Oxide. I've been looking and all I can find is that it is a broad term that can mean any N + O compound, NO2, N2O2 etc...
I wrote out:
2NO + O2 ------> 2NO2 which would give a coefficient sum of 5. Is there a certain compound which is the most common that would be referred to as Nitrogen Oxide?

I'm just not sure if I should just use NO, when it seems such a general statement. Even Wikipeida states its a general term that could refer to NO, NO2, N2O, N2O3, N2O3, N2O4, ect...

N2O3 + O2----> N2O5 Coefficient sum of 3
2NO + O2 --- > 2NO2 Coefficient sum of 5
There seem to be some multiple solutions to this question.

Answers provided to choose are: 3, 6, 4, 8 and 5 ???

2007-05-03 15:55:51 · 3 answers · asked by Jeremiah G 1