Chemistry - November 2007

30.2 g of glycerine (C3H8O3) are dissolved in
150 g of water. What is the boiling point of
the solution? (Kb of water = 0.515±C/m)
1. 103.52±C
2. 100.10±C
3. 1.13±C
4. 101.13±C
5. 0.104±C
02

2007-11-02 05:55:14 · 1 answers · asked by uwannadonkey 2

2007-11-02 05:39:06 · 1 answers · asked by swole 1

how do I calculate this

2007-11-02 05:37:00 · 3 answers · asked by swole 1

please help me and show work

2007-11-02 05:35:32 · 3 answers · asked by swole 1

How many grams (to the nearest 0.01 g) of NH4Cl (Mm = 53.49 g/mol) must be added to 650. mL of 0.894-M solution of NH3 in order to prepare a pH = 9.00 buffer?

I keep getting 17.48 but it is the wrong answer.
This is how I am working it out.
PH=pKa+log(b/a)

9=9.25+log(x/.5811)
x=.326777 mol
Then I multiply by Mm to get 17.48 grams. I am doing something wrong and don't know what it is.

2007-11-02 05:30:28 · 3 answers · asked by Anonymous

What is the partial pressure, in atm, of the N2 gas ?

2007-11-02 05:22:53 · 1 answers · asked by T-BuKeTz 2

a. is quickly elimanted by the body
b. has a short life span
c. can do the job in least concentration
d. has a long half- life
e. a,b, and c

THNX FO HELP!!!

2007-11-02 05:16:11 · 2 answers · asked by Moose On Da Loose 2

Sn(s) + 2H+(aq)-------yields---Sn 2+(aq) +H2(g
Assume ideal gas behavior

2007-11-02 04:55:47 · 1 answers · asked by Toby B 1

I have a test monday and i'm lost we are in the gas chapter and thermodynamic chapter. Could someone explain what the molecular velocities and grahams law of effusion is? What is the root-mean-square velocity of gas particles? What in the h*** is enthalpy, change in enthalpy, Hess's law, and calorimetry and how does it relate to chemical equations? My teacher is Russian and she has a strong accents o I dont understand what she is saying and the books is evem more difficult to understand with all thise different triangles and letter and stuff...i've even bought 2 different chemistry books outside of my text book and they both explain the gas and thermochemistry chapters very confusing, I just feel like giving up some1 please help. Eveytime i ask someone to help me they claim they have a paper to write or something to do that is more important than the test.

2007-11-02 03:03:56 · 4 answers · asked by YeaWutever 2

sodiumbicarbonate
zinc chloride
chlorine
flourine
lead chloride
barium chloride
coper chloride
formic acid
haemoglobine
copperoxide

2007-11-02 03:02:32 · 2 answers · asked by javed q 1

I mean the plasma found in the sun and possibly in the rings of saturn. The particles move quickly in such a plasma, so could they give an illusion of density?

2007-11-02 00:27:23 · 2 answers · asked by Roy Nicolas 5

2007-11-01 23:51:16 · 2 answers · asked by devilblues 1

need to see how to work it out so I can learn

2007-11-01 23:37:24 · 2 answers · asked by HisGlory 1

2007-11-01 20:46:56 · 6 answers · asked by soddme 1

2007-11-01 19:12:19 · 1 answers · asked by Krista J 2

i know that there are subatomic particles but if it all comes down to those three wouldn't you expect there to be 3 types of substances

2007-11-01 18:53:06 · 3 answers · asked by confused 1

2007-11-01 18:10:06 · 1 answers · asked by Anonymous

Of the following substances, which one is NOT expected to dissolve in water?
1. Ca(OH)2
2. C7H16
3. CH3OH
4. C2H5OH
5. HNO3
6. C6H12O6

2007-11-01 17:27:18 · 5 answers · asked by Anonymous

Which of the following alcohols would be the least miscible with water?
1. propanol (CH3CH2CH2OH)
2. pentanol (CH3CH2CH2CH2CH2OH)
3. ethanol (CH3CH2OH)
4. methanol (CH3OH)
5. hexanol (CH3CH2CH2CH2CH2CH2OH)

2007-11-01 17:26:06 · 2 answers · asked by Anonymous

I need help with my calculation. I'm not so sure whether i'm doing this correctly or not.
Well...i start with
SW△T(unknown metal)= SW△T(H2O) + C△T(calorimeter)
I need to find the specific heat of the unknown metal.
data I've collected from the exp are as follows:
△T of H2O in calorimeter
mass of unknown metal
mass of water used
boiling water temperature
Now..my question is where do i use the temperature of the boiling water??
For C△T, I've specific heat of calorimeter *△T in calorimeter
For SW△T(H2O), specific heat of H2O*mass of H2O used*△T(but I don't whether I should use △T of H2O in cal or boiling temperature of H2O)
Finally, SW△T(metal), mass of metal*△T(I was thinking of using △T of H2O in calorimeter since temp of H2O=temp of metal) So, please let me know which one I should use and if what I've come up with is correct. And, no disrespectful answers. Thank you!!!

2007-11-01 17:20:00 · 1 answers · asked by aji 3

1. A compound has a molar mass of 80.0g has molecules that are tetratomic.
A.How many total atoms are present in a 120.0g sample of the compound?
B. How many molecules are present in a 40.0g sample of the compound?

2.what mass, in grams, of nickel is present in a 25.00g sample of nickel ore that is 77.25% NiS? Assume that impurities present do not contain any nickel.

2007-11-01 17:12:18 · 1 answers · asked by Anonymous

2007-11-01 17:02:36 · 5 answers · asked by lightbulb627 1

S(s) + O2 (g) --> SO2 (g) Change in heat is -296 kJ/mol

a) How much heat is evolved when 275g sulfur is burned in excess O2?
b) How much heat is evolved when 25mol sulfur is burned in excess O2?

Can someone help me out on this and show me a step by step process on how to solve this?

2007-11-01 17:02:04 · 2 answers · asked by Anonymous

Place the following in order of decreasing metallic character.

P

As

K

2007-11-01 16:05:23 · 2 answers · asked by Jay H 1

From this equation, S(s) + O2(g)--->SO3(g)
Suppose exactly 5g of each reactant is available, determine which reactant is limiting. Showing steps

2007-11-01 15:53:15 · 1 answers · asked by Anonymous

2007-11-01 15:49:23 · 5 answers · asked by bro..ken.. h e a r t 1

Consider two gases, A and B, each in a 1 L container of same temperature and pressure. The mass of container A is .34 and B is .48.

a) Which gas sample has the most molecules?
b) Which gas sample has the largest average kinetic energy?
c) Which sample has fastest average velocity?
d) How can the pressure in the 2 containers be equal since gas B molecules collide with the container more frequently?

2007-11-01 15:14:02 · 1 answers · asked by Anonymous

I spilled some potassium dichromate solution (about 0.02 M; the stain's a little larger than a quarter) on my jeans. I know it's pretty toxic; are there any special precautions I should take to wash it? Can it just go in the washing machine, or should I try to get the stain out and dispose of it with lab hazmat (and if so, what should I use to wash it out?)

2007-11-01 15:11:16 · 1 answers · asked by Kat 2

........CH3
............I
CH2=C-CH2CH2CH3

2007-11-01 15:02:59 · 2 answers · asked by Jenn S 2

2007-11-01 14:58:20 · 1 answers · asked by Anonymous