Chemistry - December 2007

An ideal solution is formed by mixing liquids A and B at 298K. The vapour pressure of pure A is 180 Torr and that of pure B is 82.1 Torr. Assume that there are only A and B molecules in the vapour phase.
If the mole fraction of A in the vapour is 0.450, what is the mole fraction of A in the solution?

- much appreciated any help ne1 can give, iv been tearing my hair out and am now bald becos of this question :(

2007-12-09 00:21:27 · 1 answers · asked by Anonymous

A molar mass from freezing-point depression experiment

2007-12-09 00:20:17 · 1 answers · asked by Fafa 3

2007-12-09 00:12:58 · 1 answers · asked by Rogelio V 2

a) magnesium chloride;
b) barium chloride?

Thank you! x

2007-12-08 23:25:59 · 1 answers · asked by Anonymous

Silicon has no compounds in which the silicon atom forms double bonds with other elements. Phosphorus, by contrast, does form double bonds with other elements. Suggest why silicon and phosphorus are different in this respect.

2007-12-08 22:05:02 · 4 answers · asked by ebony 2

2007-12-08 21:40:48 · 2 answers · asked by jillian d 1

In a comparison of two radioisotopes, isotope A requires 15.0 hours for its decay rate to fall to 1/16 its initial value, while isotope B has a half-life that is 2.5 times that of A. How long does it take for the decay rate of isotope B to decrease to 1/32 of its initial value?

2007-12-08 21:35:51 · 2 answers · asked by mceb 1

The answer is 4.34 x 10^3, i don't know how to get to this answer, i have tried so many things maybe i am just over complicating it but please help.

2007-12-08 19:29:57 · 5 answers · asked by Anonymous

Here's the equation:

Zn + 2HCl ---> ZnCl2 + H2

The first two is a regular number and the other two 2's are supposed to be subscripted.

Would that make it 44.8 L of hydrogen?
It's OK to assume STP on this, according to my teacher.
Since it's H2, which would be 2 moles of hydrogen, and one mole = 22.4 L, it's 44.8 L.

Did I do that right?

2007-12-08 19:24:16 · 2 answers · asked by Anonymous

2007-12-08 18:39:48 · 2 answers · asked by Anonymous

2007-12-08 17:17:37 · 1 answers · asked by Anonymous

Does anybody know what would happen to you if you found out you had drinken a lot of water with a high pH level?

2007-12-08 16:49:00 · 3 answers · asked by Anonymous

2007-12-08 16:25:37 · 6 answers · asked by Anonymous

How much heat energy (KJ) is required to boil 2 liters of water at 25 degrees C in aluminum container (0.215 Calorie/gram *degrees C) HELP!!!

2007-12-08 16:17:49 · 2 answers · asked by anfisa03 1

HNO2(aq)+H2O(l)=H3O+(AQ)+NO2-(AQ)
A. What is the purpose of a buffer system?
B. What is the purpose of NaNO2 in the buffer?
C. How does the bugger react when some H3O+ is added?
D. How does the buffer react when sokme OH- is added?

2007-12-08 16:17:24 · 2 answers · asked by Allie C 2

A. H3PO4
B. NaNO3
C. CH3COOH AND NaCH3COO
D. HCl AND NaOH

2007-12-08 16:14:32 · 2 answers · asked by Allie C 2

a) has a fixed arrangement of particles
b) has a definite shape
c) has large distances between particles
d) has definite volume
e) is a good conductor of heat and electricity

2007-12-08 16:06:30 · 6 answers · asked by Loiman 1

What is the molarity of the acetic acid solution
CH3COOH(aq)+KOH(aq)=CH3COOK(aq)+H2O (l)

2007-12-08 16:06:02 · 2 answers · asked by Allie C 2

Calculate the following quantities.
(a) the pressure, in Torr, of 20.7 mol of an ideal gas in a volume of 175 mL at 19.0°C
__________ Torr
(b) the volume, in milliliters, of 46.0 mg H2(g) at 1.45 atm and -40.°C
__________ mL
(c) the mass, in kilograms, of 603 m3 of O2(g) at 709 Torr and 8.00°C
___________ kg
(d) the pressure, in pounds per square inch (psi), of 110 mg Ar(gas) in a 225 mL flask at 43°C
____________ psi

2007-12-08 14:33:49 · 1 answers · asked by Donna L 3

2007-12-08 14:26:33 · 6 answers · asked by princess_kc1 1

Why are the reagents used to test for cations usually alkali metal salts or ammonium salts rather than salts of other metals?

2007-12-08 14:23:51 · 3 answers · asked by david edwards 2

Combustion analysis of a hydrocarbon produces 0.396 g of CO2 and 0.163 g of H2O.
A) CH4
B) C2H6
C) C2H2
D) C2H4
E) C3H8

2007-12-08 14:23:47 · 5 answers · asked by Yoyo Y 1

2007-12-08 14:22:10 · 2 answers · asked by Yoyo Y 1

what does it measure?
the amount?

2007-12-08 12:54:20 · 15 answers · asked by KJDKLJ 1

or what things contain chromium?

2007-12-08 12:35:55 · 3 answers · asked by lismithly 2

1.calculate the work change in H at 298K and change in E for the combusition of one mole of sucrose at 25 degree C and 1atm pressure (use change in H sucrose = -2218kJ/mol)
C12H22O11(s) + 12O2(g) --> 11H2O(l) + 12CO2(g)
a. w= 0kj H=-5648kJ, and E=-5648kJ
b. w=0kj, H=5648kj and E=5648kj
c. w= 5648kj, H= 0kj and E= -5648kj
d.w=0kj , H= 0kj, and E= 0kj
e. none of the above.

2. A 73g sample of water with a temperature of 5.0 degree C is added to 271g water at 59degree C in an insulated container. What is the final temperature after thermal equillibrium is reached?
a. 0.021 degree C
b. 17 degree C
c. 32 degree C
d. 48degree C
e. 224 degree C

2007-12-08 11:44:10 · 1 answers · asked by Neha G 1

How does an electrolysis cell differ from a galvanic cell? (Select all that apply.)
A.The current of the electrolysis cell is generated outside the cell.
B.The current of the electrolysis cell is generated inside the cell.
C.The current of the galvanic cell is generated outside the cell.
D.The current of the galvanic cell is generated inside the cell.

2007-12-08 11:42:15 · 4 answers · asked by Sean H 2

CO + 2H2 -> CH3OH has a 61.3% yield. To produce 6.8 grams of CH3OH, what mass of H is necessary?

2007-12-08 11:27:52 · 2 answers · asked by Hey D 1

what are heavy metals on the table.

tell me all the elements that are heavy metal
or hit me up wit a site thx

2007-12-08 11:21:20 · 4 answers · asked by rich smith 1

33.6 L of CH4 are combusted under a dish containing ice. change in Hrxn for the combustion of CH4 is -802kJ/mol. How many grams of ice can you melt if none of the heat is lost to the environment? (change Hfus=6.00 kJ/mol)

2007-12-08 11:19:51 · 2 answers · asked by pochacco90630 1