Chemistry - May 2007

2007-05-04 13:46:43 · 3 answers · asked by ? 2

5. A sample of nitrogen occupies a volume of 546 mL at STP. What volume would the nitrogen occupy at 177 degree Celcius under a pressure of 7.35 psi?
A 91 mL
B 273 mL
C 900 mL
D 1.09 * 103 mL
E 1.80 * 103 mL
6. Calculate the volume occupied by 0.588 g of NH3 at STP, if it behaves ideally.
A 0.502L
B 0.368 L
C 0.621 L
D 0.775 L
E 0.804 L
7 At STP, 4.00L of a pure diatomic gaseous substance has a mass of 6.84 grams. The substance is
A Argon gas
B Fluorine gas
C helium gas
D Oxygen gas
E nitrogen gas.
8. Calculate the density of O2, in g/L at STP
A 0.810 g/L
B 1.43 g/L
C 1.62 g/L
D 0.714 g/L
E 1.14 g/L
9. What mass of CH4 is contained in a 500. mL sample of Ch4 at -40.0 degress Celcius and 300. torr?
A 0.0870 g
B 0.165 g
C 0.322 g
D 0.734 g
E 1.06 g
10. What is the pressure exerted by a misture of 14.0 grams of N2, 71.0 grams of Cl2 and 16.0 grams of He in a 50.0 liter container at 0 celcius?
A 2.47
B 6 .80
C 14.1
D 4. 66
E. 0.687
all at atm

2007-05-04 13:39:06 · 1 answers · asked by wqel12 1

inead a gel like silicone that when exposed to cold tempetrues wil harden.

2007-05-04 13:05:38 · 1 answers · asked by Teddy 1

Is the ΔS positive or negative and is the ΔG positive or negative; And, at what temperature.

I mean, for example, ΔS positive and ΔG negative at high temperatures only.

2007-05-04 12:40:52 · 1 answers · asked by W 1

Calculating actual yield of CO2
• d) The amount of gas collected in the first trial is __________mL and in the second trial is ___________mL. Change the volume of CO2 trapped in your bottle from milliliters to liters. Calculate the average volume of CO2 in liters. AVERAGE amount of CO2 collected is ________L.
• e) Use the Ideal Gas Law, PV = nRT, to calculate number of moles of CO2 trapped in your bottle. This is the actual yield of CO2. Assume that P is 1.0 atm and T is 293 K (room temperature). The gas constant, R, is (0.0821 liter-atm / mole-K); V is AVERAGE volume of trapped CO2 in liters calculated in (d); and n is the average number of moles of CO2 trapped in your bottle O2
n = PV/RT = {1 atm x V} / {(0.0821 L-atm / mole-K) x (293 K)}
You don't have to worry this long equation because it boils down to a simple equation that you use:
actual yield in moles = n = V x 0.0416
First, fill in the value for the AVERAGE volume of CO2 collected, V. The actual yield of CO2 is _________moles

2007-05-04 12:36:42 · 2 answers · asked by Kristina H 1

If no precipitate forms, then the equasion is unnessary; just state that no precipitate formed.

1. Ca(NO3)2(aq) and Na2S(aq)
2. Na3PO4(aq) and Pb(NO3)2(aq)
3. FeCl3(aq) and NH4NO3(aq)

2007-05-04 11:28:35 · 1 answers · asked by Anonymous

Please explain the order of water solubilities for the compounds in each of the following groups:

a) Ethanol>Choloroethane>Ethane

b) Methanol>Ethanol>1-propanol

2007-05-04 11:11:33 · 2 answers · asked by flyboy87 1

2007-05-04 10:52:12 · 1 answers · asked by Anonymous

The question is : In the titration of an impure sample of KHP, it was found that 36.0mL of .100 Mole NaOH was required to react completely with .765g of sample. What is the percentage of KHP in this sample?

2007-05-04 10:51:11 · 1 answers · asked by chris j 1

less painful than a tooth extraction.

any method of execution is justified because it only happens once to a person.

I think Cyanide is the gently option.

2007-05-04 10:43:32 · 3 answers · asked by Do not delete. 1

I know how to solve this problem if I have more information, but I don't know how to do the problem with only this information, although, it seems pretty simple.

Thanks.

2007-05-04 10:22:20 · 3 answers · asked by christopher239938 1

cyber skin is a synthetic material used in sex toys to mimic human skin. i need it for another non erotic purpose. what is the method i need to follow assuming i have a normal lab and chemical materials?

2007-05-04 09:56:57 · 1 answers · asked by billy t 1

2007-05-04 09:28:33 · 10 answers · asked by Scrap master 2

Calculate the mass in grams of 8.35 *10^22 molecules of CBr4

2007-05-04 09:09:52 · 6 answers · asked by Anonymous

How do you find the boiling point. I read up on Wikipedia and my chem book and I can't find out how to do it. Thanks very much...chem homework is really driving me crazy today.

I have the following problem:

Which substance will have the highest boiling point?

a. They will all have similar boiling points because they have similar molar masses.
b. CH3CH2CH3
c. CH3Cl
d. CH3CH2OH

2007-05-04 09:02:32 · 7 answers · asked by christopher239938 1

1. which metals will be able to reduce copper ions in solution?

A. Potassium
B. Sodium
C. Calcium
D. Magnesium
E. Aluminum
F. Zinc
G. Iron
H. Lead
I. Copper
J. silver
K. gold

2. will copper be able to replace zinc ions in solution?why?

3.which metal will not be able to be oxidized by any of the other meatals listed?

Not Homework, dont answer with a stupid remark if you know it I would appreciate it. just getting study material ready with practice questions!so please help if you can! Thanx to all the ones who answer respectfully.

2007-05-04 08:55:06 · 3 answers · asked by MEB 2

Also the difference between iodine and iodide? I think it is somthing to do with their ions, where ammonia has a neutral charge but ammonium is positively charged.

2007-05-04 08:49:45 · 16 answers · asked by Anonymous

a. Na2CO3
b. PbSO4
c. AgBr
d. K2S

I know how to find out if it is soluble if I am given the solubility of of the liquid in water at a cetain temp., but I do not know how to do it if I am not given that information. Thanks for the help.

2007-05-04 08:47:30 · 6 answers · asked by christopher239938 1

1)strong base
2)weak acid
3)weak base
4)strong acid
5) neutral solution

2007-05-04 08:44:42 · 13 answers · asked by princess 1

use ph titration curves for HCL, ethanoic acid and phosphoric acid.. over which reigons is the system behaving as a buffer? Explain

2007-05-04 08:44:18 · 2 answers · asked by Adam 1

I know chemistry is like the stuff you learn in school, but what exactly is amchemy? I haeard s is something you do spiritually or something idk? can someone give me some good info on this?

2007-05-04 08:42:16 · 8 answers · asked by ledzep513 3

2007-05-04 08:18:12 · 2 answers · asked by Anonymous

Use the Gibbs free energy equation shown below to determine the temperature in degrees Celsius above which decomposition of KClO4 is spontaneous.

ΔG = ΔH – TΔS

2KClO4(s) → 2KClO3(s) + O2(g)

ΔH°f = 70.2 kJ

ΔS°f = 189.3 J/K

_______°C

2007-05-04 07:41:09 · 4 answers · asked by MEB 2

2007-05-04 07:38:29 · 3 answers · asked by Ramona W F 1

(they are full of gas)

Which answer is correct?
a. The first container contains twice as many gas molecules as the second.
b. The smaller container will have twice the pressure as that of the larger container as the temperature increases.
c. The smaller tank will develop a pressure change twice as quickly as the larger.
d. These choices are all correct.

2007-05-04 07:38:13 · 1 answers · asked by Anonymous

2007-05-04 07:07:49 · 2 answers · asked by Anonymous

It seems that a lot of the Yahoo Chemistry Section questions deal with balancing equations, looking up data and other things one must be able to do to become proficient at chemisty. Too often, in my opinion, we with knowledge simply provide answers rather that take the opportunity to teach the asker how to do something. Learning chemisty is a matter of learning the principles and how to apply them. Balancing equations is a good place to start.

In my perfect world no one here would ever balance another equation for an asker but would offer hints about doing it and let the asker struggle until he gets it. This is how learning happens. Why are we helping to undercut this process? Your thoughts????

2007-05-04 06:49:26 · 7 answers · asked by Flyboy 6

Prideict whether a precipitate will form when the following solutions are mixed.
Lead (II) acetate, Pb(CH3COO)2, and rubidium bromide, RbBr.
First you have to balance the equation.
Any help with this would be appreciated

2007-05-04 05:40:44 · 4 answers · asked by flowers4eden 1

also if potassium has more than one polysulphide, what are their recations with silver? Can I control the colour change produced on the surface of the silver by controlling (for eg) Ph? I want the reaction to stop when the silver becomes irridescent blue and purple to obtain consistency between pieces (I'm a jewellery making ex-chemist!!) without the trial and error I currently rely on!

2007-05-04 03:20:57 · 3 answers · asked by Amanda B 1

2007-05-04 03:20:18 · 13 answers · asked by bananafudge93 1