Chemistry - November 2007

I need to find the thinkness of a 35cm squared peice of aluminum that weighs 1.00grams.

Aluminum has a density of 2.7grams/cm cubed

2007-11-12 14:19:16 · 1 answers · asked by Anonymous

I need this for a chem paper. Answer asap would be greatly appreciated!

2007-11-12 14:07:15 · 1 answers · asked by vikingboy1927 2

I'm having problems with all these weird products in Chem problems. I don't see how I could have predicted these. Can someone explain the logic behind these to me. Here are a few examples.

Pure phosphorous burned in air.
P + O2 yields P4O10
Why?

Access concentrated HCl is added to 1.0M solution of CoCl2.
HCl + CoCl2 yields H2 + CoCl3
What the %^#^!?

Solid cesium oxide is added to water.
Cs2O + H2O yields 2Cs + 2OH-
Huh?

A solution of potassium hydroxide is added to solid ammonium chloride.
I don't even know about this one.

And what's up with sulfuric acid?
H2SO4 + anything yields whatever it wants apparently.

I seriously need help.

2007-11-12 14:02:05 · 2 answers · asked by Chris H 1

In a lab we need to separate 3 substances so they come out separtely. The three substances are
1. Salt
2. Sand
3. Iron Fillings

how can i separate these three substances so that all three come out in three diferent piles of differnet substances.

if you dont understand contact me at samusai12@gmail.com

PLZ DONT SEND ME SPAM!!

2007-11-12 13:53:54 · 10 answers · asked by KoolDude574 1

Give the maximum number of electrons in an atom that can have these quantum numbers.
n = 4, l = 0, m = 0

2007-11-12 13:53:03 · 2 answers · asked by Somerandomguy 1

I am having trouble finding the physical and chemical properties of Calcium, especially because I dont understand a lot of what I am reading. Could someone please help me out with this?

Thanks soo much. :)

2007-11-12 13:43:00 · 3 answers · asked by Anonymous

What is the solubility of MX2
in 0.11 M M(NO3)2?

MX2 --> M + 2X (ksp=4.79e-13)

i...enough....11.........0
d..-x..............+x..........+2X
f...some........(.11+x)....2X

I am solving

Ksp=[M]*[X]^2
4.79e-13=(.11+X)(2x)^2
I keep getting the answer 1e-6

I don't know what I am doing wrong. Please explain if you can help. Any help is appreciated :)

2007-11-12 13:27:07 · 1 answers · asked by Anonymous

2007-11-12 13:26:00 · 1 answers · asked by guessx3 2

Please help.

1. Find the energy required to ionize a ground state hydrogen atom. That is, what is the energy required to make the transition from n = 1 to n = inifinite.

I'm assuming use E = -R_h * Z^2 ( 1/n^2 final - 1/n^2 initial )
where n final is 0 (because infinite makes it equal to 0) and n initial is 1 and z = 1???

2. Calculate the frequency of light emitted when the electron in an He^+ ion relaxes from the third energy level to the first energy level.

I don't get this, Am i suppose to use the equation above but i need to change n final to 1 and n initial to 2 while changing z to 2 since 2 is He^+ atomic number and solve?

3. If an electron in a hydrogen atom relaxes to the second energy level, emitting a photon of wavelength 410.2 nm, what higher energy level did it start at?

I use e = hv, c = lambda * v (V = wavelength)

find the energy and plug into Rydberg's equation and solve right?

Thx =)

2007-11-12 13:17:34 · 1 answers · asked by Anonymous

how many electrons are found in the outer shell of metalloids?

oh, and i have one more question.

What element is the most abundant element in the universe?

2007-11-12 12:58:46 · 2 answers · asked by Anonymous

I just cannot figure out what I am doing...How do you balance them. I do understand the canceling out of spectators, but when I write out the equation, I get confused on what is written first and which ones stay together and break apart. For example...
CaCl2 (aq) + K3PO4 ----> what goes here??? And once you figure it out and write it all out to see the spectators which ones stay together and which ones part???
PLEASE SOMEONE HELP....

2007-11-12 12:58:16 · 7 answers · asked by stacy a 2

2007-11-12 12:46:35 · 4 answers · asked by Emerson 5

If the percent yield of the above reaction is found to be 90.02 %, how many grams of H2O are produced from the complete reaction of 71.85 g of LiOH ?

2007-11-12 12:45:01 · 2 answers · asked by chemical.garry 1

A)Write a correctly balanced equation for this reaction:

B) Determine the theoretical Yield of ethyl alcohol if 4.6 grams of ethylene is used?

C) What is the Percent yeild of this reaction if 4.6g of ethlene gives 4.7g of ethyl alcohol.

2007-11-12 12:39:35 · 1 answers · asked by Mzbee 1

Do I have these correct:
A steel cylinder with a vol of 15.0 L is filled with 50g of nitrogen gas at 25 degrees celcius. What is the pressure of the N2 in the cylinder?

I got 5.82 atm's of pressure


2)
A container filled with 4.0 x 10^22 molecules of O2 at 5 degrees celcius and 845 mm HG. What is the volume in ML in the container

I got 1.36L which is .001mL

2007-11-12 12:31:48 · 3 answers · asked by shirah d 2

2007-11-12 12:26:24 · 2 answers · asked by Tammy 1

2007-11-12 11:23:23 · 11 answers · asked by Keyrose. 1

artificially make rain...like "Artificial precipitation induction"

2007-11-12 11:22:34 · 4 answers · asked by love*pink 3

2007-11-12 11:16:32 · 2 answers · asked by lindsayhoops 1

1) Fe + CuSO4 ---> FeSO4 + Cu
2) 2 AgNO3 + Cu ---> 2 Ag + Cu(NO3)2
3) BaCl2 + NaSO4 ---> BaSO4 + NaCl2

Please explain how you got each. Thanks for the help!

2007-11-12 11:12:52 · 1 answers · asked by Anonymous

is xenon a radioactive element.

i need help. need this for chemistry project

2007-11-12 11:12:50 · 0 answers · asked by Anonymous

The element silver (Ag) has two naturally occuring isotopes:
Ag-107 with a mass of 106.905 amu and
Ag-109

Silver consists of 51.82% Ag-107 and has an average atomic mass of 107.868 amu.

Calculate the mass of Ag-109

plzzzz

2007-11-12 10:50:24 · 3 answers · asked by Sina 2

The element exists in nature as 2 isotopes.

^153Eu the mass is 152.9209
^151Eu the mass is 150.9196

The average atomic mass of europium is 151.96 amu.

Calculate the relative abundance of the europium isotopes.
pleaseee

give me the equation so i could understand

2007-11-12 10:42:40 · 1 answers · asked by Sina 2

The element exists in nature as 2 isotopes.
^151Eu has a mass of 152.9209amu.
^153 Eu has a mass of 152.9209 amu.

The average atomic mass of europium is 151.96 amu.

Calculate the relative abundance of the europium isotopes.
pleaseee

give me the equation so i could understand

2007-11-12 10:26:28 · 4 answers · asked by Sina 2

Underline the reducing agent and draw a box around the oxidizing agent.


Br2(l)--> Br-(aq) + Br(O3)- (aq)

CN- (aq) + [Fe(CN6]3- (aq)--> OCN- (aq) + [Fe(CN)64- (aq)

thanks

2007-11-12 10:18:48 · 1 answers · asked by Anonymous

Underline the reducing agent and draw a box around the oxidizing agent.

Hg(s) + (NO3)- (aq) + Cl-(aq) -->Hg(Cl4)2- (aq) + NO(g) +S(s)


I2(s) + S2(O3)2- (aq) --> I-(aq) +S4(O6)2- (aq)

thanks

2007-11-12 10:15:54 · 1 answers · asked by Anonymous

What term is used to describe the 4 in the expression
4CA(NO3)2?

A. Coefficient
B. Formula
C. Subscript
D. Symbol

2007-11-12 09:24:57 · 4 answers · asked by dddd d 1

The combustion of what volume of ethane (C2H6), measured at 23.0 C and 752 mmHg, would be required to heat 855 g of water from 25.0 C to 98.0 C?

2007-11-12 09:21:31 · 1 answers · asked by SilentFox12345 3

1. Na2SO4
2. NaCl
3. NaNO3

2007-11-12 09:17:16 · 2 answers · asked by Tina D 1

Determine the percent yield for the reaction between 6.92 grams of K and 4.28 grams of O2 if 7.36grams of KO2 is probduced.

2007-11-12 09:13:27 · 2 answers · asked by Adawg 3