Chemistry - April 2007

2007-04-23 01:45:32 · 5 answers · asked by Anonymous

Hey guys, need help with these questions..

1. Two items have a flash points of -15 degrees Fahrenheit, and 80 degrees Celsius.. which one poses the greater fire hazard?

2. Upper explosive limit of liquid cumene is 0.9% and 6.5% When exposed to an ignition source, will cumene vapors ignore in the air at each of the following: 10%, 0.09%, and 6% (basically yes or no)

2007-04-23 01:42:44 · 3 answers · asked by aa 1

Well, I was answering my homework and though I was doing pretty well until I ran across this equation:
FeS + HCl ----> H2S FECl

My problem is with the H2S, whenever I put a number beside it to balance the S the H gets unbalanced and it starts a never ending cycle.

Can I put a number in between it?
Like:
2FeS + 2HCl -----> H2S + 2Fe'2'Cl ?

2007-04-23 01:32:56 · 2 answers · asked by Xianpu 4

what is the balanced equation of copper being extracted from cuprite by heating it with carbon?

2007-04-23 01:26:20 · 2 answers · asked by Anonymous

Sometimes when I boil my water in the microwave for my morning coffee and add sugar to it, it fizzles, but not always. Sometimes it doesn't fizzle, sometimes it fizzles a lot, and sometimes just barely. I've tried adding the sugar before and after I add my instant coffee. This might sound like a stupid question but it's been really bugging me for not knowing why. I don't know if this has any significance but I live in China and maybe they put some kind of chemicals into their water that causes this reaction. Anyway, just makes me curious.

2007-04-23 01:21:09 · 9 answers · asked by swegricht 1

2007-04-23 01:16:27 · 5 answers · asked by ganesh - 1

2007-04-23 00:44:17 · 3 answers · asked by Anonymous

2007-04-22 23:01:34 · 1 answers · asked by p2 1

OK, its about the combined gas law and stuff like that... here it is:

"We can estimate the temperature of the centre of the sun by assuming it consists of gases with a average molar mass of 2.00 g/mol. If the density is 1.40 g/cm^3 at a pressure of 1.30 x 10^9 atm, calculate the temperature in degrees Celsius.

OK, now heres the tricky part. My teacher wont allow us to use the modified gas law that incorporates density and molar mass in PV=nRT. He wants us to use stoichiometry and other methods to somehow solve this problem. Im stumped on how to get the Volume and the number of moles from the info given.

Some help would be appreciated.

2007-04-22 20:42:36 · 1 answers · asked by Anonymous

2007-04-22 20:28:52 · 2 answers · asked by T_dizzler 1

Can anyone help me find the molecular shape of ICl5 with all the bond angles?

2007-04-22 20:10:46 · 2 answers · asked by Anonymous

n produced in each carbonate reaction? (show work)

Reaction #1- 0.5 g NH4HCO3=_____ g CO2

Reaction #2- 0.5 g NaHCO3=_______ g CO2

Reaction #3- 0.5 g KHCO3=________ g CO2

also what type of yield did you find in this problem? stoichiometry

2007-04-22 19:54:14 · 1 answers · asked by brent 1

The system starts with a mole of microstates and ends with a half mole of microstates.

2007-04-22 19:21:22 · 1 answers · asked by T_dizzler 1

2007-04-22 18:40:36 · 1 answers · asked by nancy_loya 2

When sulphuric acid added to carbohydrate( white sugar), the solid turns black and fume appears ? What chemical reactions are happening?

When sulphuric acid is added to meat, some red liquid leaks, what is indeed happening?

2007-04-22 18:26:12 · 3 answers · asked by Anonymous

Thanks

2007-04-22 18:20:48 · 1 answers · asked by monse 2

A salt MCl2 has a Ksp of 2.00×10-21. What is its solubility?

The metal M2+ forms a complex in A(aq) [MA4]2+ with Kf = 2.24×108.
What is the solubility of MCl2 in 1.9 M A(aq)?

2007-04-22 18:05:35 · 1 answers · asked by vgrapid01 2

What is the pH of a 0.6 M solution of a weak base B with Kb = 1.41×10-5?

A 25.0 mL sample of the base is titrated against 0.75 M HCl. What is the pH after 5.0 mL of the acid has been added?

What is the pH after 10.0 mL of acid has been added?

What is the pH when 30.0 mL of acid have been added?

What is the pH at the equivalence point?

What volume of base must be added to reach the equivalence point?

2007-04-22 18:04:02 · 2 answers · asked by vgrapid01 2

2007-04-22 18:01:15 · 1 answers · asked by jj 5

2007-04-22 17:55:24 · 3 answers · asked by kneeplay5 1

Thanks a lot for your help

2007-04-22 17:54:10 · 1 answers · asked by monse 2

2007-04-22 17:54:05 · 7 answers · asked by Anonymous

Briefly explain your answer and support it with mathematics

2007-04-22 17:52:39 · 2 answers · asked by jalabala6 1

The barium sulfate precipitate is filtered and redissolved in hot water. The barium is then titrated with 0.1567 M EDTA. If it takes 12.66 mLs of EDTA solution to reach the endpoint, what was the concentration of the sulfate in the original 25.00 mL sample?

2007-04-22 17:48:31 · 2 answers · asked by jalabala6 1

If I added 100 mL of water to this solution, would I expect the fraction of dissociation to increase or decrease?

2007-04-22 17:45:23 · 1 answers · asked by jalabala6 1

please give me the medical application?

2007-04-22 17:44:49 · 2 answers · asked by Anonymous

2007-04-22 17:43:46 · 1 answers · asked by jalabala6 1

I'm using a salt bridge to keep the anode/cathode solutions from mixing.

I've still been told it is the same as electrolysis of water. I don't believe this because the anode side has a pretty strong smell, but I'm not sure what it is.

So can I or can I not get HNO3 and KOH? What am I smelling?

2007-04-22 17:42:26 · 2 answers · asked by pirate77 2

Homogeneous solutions must be uniform in appearance.
A solute is the part of a solution that dissolves.
Either the solvent or the solute in every solution must be a liquid.
Colloids are solutions.

2007-04-22 17:15:55 · 3 answers · asked by Heavy Metal 3

water (H2O)
ethyl alcohol (C2H5OH)
sodium chloride (NaCl)
butane (CH3CH2CH2CH3)

2007-04-22 17:14:30 · 1 answers · asked by Heavy Metal 3