Chemistry - October 2007

I thought they should not make a reaction cause Cu is lower on the activity series than Fe, as with I2 and H.

2007-10-26 06:40:32 · 1 answers · asked by kooldogy88 1

2007-10-26 06:28:57 · 4 answers · asked by suman 2

and would a percipitate form??

2007-10-26 06:15:12 · 4 answers · asked by Ash and june 2

BENZEN (C6H6)
Melting Point: 5.5C
Boiling Point: 80C
Hf: 127J/g
Hv: 551 J/g
Sample Size: 100g
Sp. Heat (solid): 1.5 J/gC
Sp. Heat (liquid): 17 J/gC
Sp. Heat (gas): 1.0 J/gC
Rate of heating: 400 J/min

How much heat is required to melt the sample at the melting point?
How much heat is required to boil the sample at the boiling point?
How much heat is required to raise the temperature of the sample from 20°C below melting point to the melting point?
What is the difference in temperature between melting point and boiling point?
How much heat is required to raise the temperature of the sample of the liquid phase from the end of melting to the beginning of boiling?
How much heat is required to raise the temperature of the sample of the gas phase from the end of boiling to 20°C above the boiling point?

I need equations, you don't have to do the work!

2007-10-26 06:07:23 · 2 answers · asked by Anonymous

2007-10-26 05:56:27 · 3 answers · asked by nett 1

A balloon filled with 31.9 mol helium has a volume of 715. L at 0.0°C and 1.00 atm pressure. The temperature of the balloon is increased to 68.0°C as it expands to a volume of 893. L, the pressure remaining constant. Calculate q, w, and E for the helium in the balloon. (The molar heat capacity for helium gas is 20.8 J/°C·mol.)

2007-10-26 05:30:44 · 1 answers · asked by toocool 1

A 1.397 g sample of thymol, C10H14O(s) (a preservative and a mold and mildew preventative), is burned in a bomb calorimeter assembly. The temperature increase is 11.23°C, and the heat capacity of the bomb calorimeter is 4.68 kJ/°C. What is the heat of combustion of thymol, expressed in kilojoules per mole of C10H14O?

2007-10-26 05:29:50 · 1 answers · asked by toocool 1

Salicylic acid, C7H6O3, has been suggested as a calorimetric standard. Its heat of combustion is -3.023 103 kJ/mol C7H6O3. From the following data determine the heat capacity of a bomb calorimeter assembly (that is, the bomb, water, stirrer, thermometer, wires, and so forth).


mass of salicylic acid burned: 1.111 g
initial calorimeter temperature: 23.07°C
final calorimeter temperature: 29.55°C

2007-10-26 05:29:25 · 1 answers · asked by toocool 1

2007-10-26 05:21:05 · 12 answers · asked by jimmyjoe 1

2007-10-26 03:21:48 · 3 answers · asked by jnester0289 1

100.0 mL of 2.00 M HBr is mixed with 100.0 mL of 2.00 M KOH in a coffee-cup calorimeter. The temperature of the solution increases from 20.0 C as a result of the reaction. Assume that the calorimeter loses a negligible amount of heat, that the total volume of the final solution is 200.0 mL, the density of the solution is 1.00 g/mL, and that the specific heat of the solution is 4.18 J/g-K

2007-10-26 03:17:53 · 2 answers · asked by jnester0289 1

Quantum dot contains 10,000 atoms of silicon. Calculate mass (g), volume (cm^3), and if dot is acute, length (mass & mm).

Thanks alot!

2007-10-26 03:03:07 · 1 answers · asked by Caramel 2

given that the pKb of iodate ion IO3- is 13.83, find the quotient [HIO3]/[IO3-] in a solution of sodium iodate at pH 6.00

2007-10-26 02:50:34 · 1 answers · asked by Anonymous

Can anyone help me answer my question :)

What is meant by ionic and metallic bonding, using sodium chloride and copper as examples.

2007-10-26 02:40:19 · 1 answers · asked by Anonymous

Just the other day I found a note that my husband wrote. It reads as follows: "The bearer of this note is trying to tell you where a booby trap or a mine is located, if he does you should reward him kindly." There is a picture of an explosion on the note. I know he knows what he`s talking about because he blew up an owls nest a few years back which was near the place he was working--he`s Native American and they just don`t like owls.

2007-10-26 02:20:11 · 4 answers · asked by Ashlee C 1

Hello. In my chemistry class we were talking about boiling points and pressure. My instructor brought up this question: why does it take longer for an egg to cook in Colorado than in NY? I understand that Colorado is at a higher elevation, but I do not understand how that relates to cooking time. I think this is a simple concept to grasp, I just don't understand why I can't seem to grasp it. Please, with not a bunch of confusing chemistry jargon or equations, SOMEONE BREAK IT DOWN FOR ME!!!

2007-10-26 02:16:28 · 5 answers · asked by annied 1

Arrange the following metals in the order of their decreasing chemical activity :
Magnesium, Potassium, Iron, Gold

2007-10-25 22:22:19 · 4 answers · asked by meow 3

The problem is that I dont have easy access to chemicals and I can not get them in small quantity. So buying in bulk means that they are gonna be expensive(I mean the total cost). I already have KMnO4 and I want another oxidiser. Which one shall I prefer?

2007-10-25 21:08:42 · 3 answers · asked by blahblah82473 1

a semipermeable membrane separates a 4%(m/) NaCl solution from a 2% (m/m) NaCl solution. INitially, the two solution levels are the same, but over time the levels become different.
a. which solution level will riseand which will drop?
b. which solution becomes more concentrated
c. in which direction, if any, is there a net flow of solvent
d. in which direction, if any, is there a net flow of solute

please show your workkkk

2007-10-25 20:19:04 · 1 answers · asked by bubbles7070 2

How many grams of NaBr were added....?

At 37.0C, the vapor pressure of 355 g of water was reduced from 6.20×10−2 atm to 5.20×10−2atm by the addition of NaBr.

This is what I did:
Del P = x Po
.062 - .052 = x (.062)
x= .001 / .062
x=0.1612

Now # of moles in water:
355/18.02 = 19.7mol

Now use mole fraction:
xH2O = mol h2o / mol h20 + mol NaBr
mol NaBr = mol h20 / xH20 (xH20)
mol Nabr = 1 / .16
mol = 6.25

Convert moles to grams
6.25 x 103 = 643.75grams

IS this right?
Thanks!

2007-10-25 18:48:45 · 2 answers · asked by Anonymous

At temperatures greater than 100oC, condensation is "BLANK" because the absolute value of the TS term in the Gibbs free energy equation is "BLANK" the absolute value of the H.

I think the answers are not spontaneous and less than. Can anyone confirm this?

2007-10-25 18:13:22 · 1 answers · asked by Anonymous

You have 100 mL of water and you add 1 drop (0.05 mL) of a 1 M solution to it. What's the concentration of the solution?

2007-10-25 17:50:03 · 1 answers · asked by reggielarue 2

2007-10-25 17:42:32 · 4 answers · asked by George 2

A solution of ethanol (C2H5OH) in water is prepared by dissolving 55.0 mL of ethanol (density = 0.79 g/cm3) in enough water to make 215.0 mL of solution.

What is the molarity of the ethanol in this solution?

2007-10-25 17:27:41 · 1 answers · asked by 港式奶茶 3

A chemist started to carry out column chromatography on Friday afternoon, reached the point at which the two compounds being separated were about three-fourths of the way down the column, and then returned on Monday to find that the compound came off the column as a mixture. Sepculate the reason for this. The column had not run dry over the weekend

2007-10-25 17:23:40 · 2 answers · asked by *QP* 1

If I remember the elements in a polyatomic ion, could i figure out the charge without memorizing it?

2007-10-25 16:30:39 · 4 answers · asked by Dmac 2

I'm not sure how so yeah....

2007-10-25 16:26:42 · 11 answers · asked by thepizzaboy95 2

2007-10-25 16:18:43 · 9 answers · asked by yerafdog 1

Hydrogen sulfide can be deteced at a concentration of 2.00ppb. The density of air is 1.2929 g/L

1)What is the concentation of H2S in mg/L at the detection level?

2) The lethal dose of hydrogen sulfide by inhalation for rats is 7.13×10−4g/L . What is this lethal dose in ppm?

2007-10-25 16:13:12 · 1 answers · asked by Anonymous

What is w (work) when 1.47 kg of H2O(liquid), initially at 25 degrees is converted into water vapour at 151 degrees against a constant external pressure of 1 atm.? Assume that the vapour behaves ideally and that the density of liquid water is 1 g/mL.


ok so I know I have to use this formula
W = -P ext (Vgas-Vliquid)

for v gas, we use v= nRT/P
but do i subtract temperatures or what? what about P ??
clue me in folks asap please!!!!!!!!

2007-10-25 16:12:04 · 1 answers · asked by Curious 1