Chemistry - December 2007

does anybody know at what temperature does phosphorus catch on fire at

2007-12-12 16:09:12 · 1 answers · asked by Anonymous

QUESTION CNT... is an oxidizing agent needed?
1)CH3CH2CH=CH2 2) CH3CH2CH2CH2Br 3) (CH3CH2CH2CH2)2O 4) CH3CH2CH2CH=O

Thank you.

2007-12-12 14:49:37 · 2 answers · asked by Anonymous

Chemistry Problem: (I just cant solve it)

What is the minimum speed at which a 1 kg snowball is thrown at a wall so that it will vaporize on impact? Assume frictionless, no speed loss or gain, etc.

My chemistry teacher said it had something to do with the specific heat of Ice, but I cannot solve it.

2007-12-12 14:48:43 · 1 answers · asked by J PAO 1

ok i think it's a compound but i don't know.... i know that the amount of gold used in jewelry is made from like 10 to 22 karats?


help me out

2007-12-12 14:19:54 · 8 answers · asked by katiebug 2

I have to do a report in science on Molybdenum, does anyone know anything about it? Any experts on the elements? Websites on Molybdenum aren't very helpful, so, please help, it's due in two days.

2007-12-12 14:14:15 · 1 answers · asked by Tiki Tiki 2

Calculate the hydronium ion concentration and pH of the the solution that results when 22.0mL of 0.15M acetic acid is mixed with 22.0mL 0.15M NaOH.

2007-12-12 14:12:20 · 2 answers · asked by Anonymous

How many grams of KCl (molar mass = 74.55 g) will be produced from the reaction of 50 mL of .3 M KOH with axcess HCl?
KOH(aq) + HCl(aq) --> KCl(aq) + H2O (l)
1. 9.31 g
2. 1.12 g
3. .876 g
4. 4.65 g
5. 6.98 g

2007-12-12 13:52:56 · 4 answers · asked by Anonymous

ok...so i did a lab in chem. and i dont understand two of the questions..well first things first...we are determining the formula for magnesium sulfate...

i already posted this once but i have another question...

i also meant to ask why it is necessary to let the evaporating dish cool before measuring the mass?

and thanks sooooo much to the others that have already helped me with my questions! your heroes!

2007-12-12 13:29:18 · 3 answers · asked by Anonymous

carbonate

hydrogen carbonate

acetate

cyanide

2007-12-12 13:06:39 · 2 answers · asked by Anonymous

2007-12-12 13:03:16 · 4 answers · asked by Anonymous

A 0.309-g sample of coal is burned in a bomb calorimeter with a heat capacity of 4.62 kJ/oC. The temperature in the calorimeter rises from 20.45oC to 22.28oC. Calculate the heat of combustion of the coal in kJ/g.


trying to finish a study guide ughh.

2007-12-12 13:02:24 · 1 answers · asked by Anonymous

ok...so i did a lab in chem. and i dont understand two of the questions..well first things first...we are determining the formula for magnesium sulfate...

why should the mass of the evaporating dish be measured immediately after it cools, and not later?

i dont know that one...

and it said to use a desiccator but my class didnt...

how would my results be affected if we would have used a desiccator when cooling the evaporating dish and contents?

PLEASE HELP!!!

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

2007-12-12 12:56:27 · 2 answers · asked by Anonymous

I've been working on this one for ages, but can't seem to get it to balance.

2007-12-12 09:45:43 · 7 answers · asked by Anonymous

3.37 g/cm^3 = ______ kg/m^3

a. 333.7
b. 3.337 x 10^-5
c. 3.337 x 10^-9
d. .3337
3. 3337

I got C when I did it but I know the correct answer is E. How do you do this?

2007-12-12 09:29:04 · 3 answers · asked by Anonymous

i know that its is a halogen and therefore should be diatomic but the internet moslty says that it is just At. not At2

2007-12-12 09:19:21 · 3 answers · asked by poo 2

How many grams of oxygen are formed at decomposition 490g potassium chloride

2007-12-12 09:17:38 · 3 answers · asked by A Student 1

A) Inspecting the chemical equation
B. Balancing the chemical equation
C. laboratory analysis
D. writing a word equation

2007-12-12 09:17:02 · 1 answers · asked by Anonymous

The human body obtains 965KJ of energy from a candy bar.
If this energy were used to vaporize water at 100.0 degrees C. how much water (in liters) could be vaporized? (Assume the density of water is 1.00g/mL).

I have been working on this equation for a while now, so any help would be appreciated. THANKS

2007-12-12 08:55:25 · 2 answers · asked by FANTASY 2

2007-12-12 08:50:17 · 8 answers · asked by trek trek 5

2007-12-12 08:37:37 · 2 answers · asked by trek trek 5

The question is, Since copper does not have a "u" in it, then why is it used in the atomic symbol for copper?

2007-12-12 08:31:21 · 15 answers · asked by summerlove32 2

how is it produced and purified
important uses of it

2007-12-12 08:03:24 · 1 answers · asked by kikikara16 1

How many moles of solute particles are present in 1 L of each of the following aqueous solutions?
(a) 0.4 M KI
mol
(b) 0.090 M HNO3
mol
(c) 10-4 M K2SO4
mol
(d) 0.07 M ethanol (C2H5OH)

2007-12-12 07:58:56 · 5 answers · asked by cntrstrk132 1

which ion in each pair has the smaller atomic radius

K- or O2-
Ba2+ or I-
Al3+ or P3-
K+ or Cs-
Fe2+ or Fe3+
F- or S2-

2007-12-12 07:53:02 · 2 answers · asked by Tr4ck4Inc@ 2

I missed two classes with strep, and this was covered in one of them. The book isn't working for me. Can someone walk me through, and give me an answer so I know that I'm doing it right? Please and thanks.

1) Green light has a wavelength of 5.0 x 10^2 nm. What is the energy, in joules, of one photon of green light? What is the energy, in joules, of 1.0 mol of photons of green light?

2) Calculate the wavelength of an electron with a mass of 9.11 x 10^-31 kg and a speed of 2.5 x 10^6 m.s^-1.

2007-12-12 07:33:27 · 5 answers · asked by Anonymous

2007-12-12 07:30:44 · 2 answers · asked by Anonymous

Is sigma 2p filled first or pi 2p?

2007-12-12 07:30:01 · 1 answers · asked by Sam 6

for a Nickel-Barium cell: idnetify the cathode, anode, redox reaction, positive voltage and indicate the direction of electron flow.
(this is a cell that has a salt bridge, a wire connecting Ni and Ba, and voltmeter)

can some help me out PLEASE?
thanks:)

2007-12-12 07:23:17 · 1 answers · asked by xyz 1

calculate the change that occurs in pH when 0.010 moles of gaseous HCl is added to 1.0L of the following solution:
Solution A: 6.00M HC2H3O2 and 5.00M NaC2H3O2

pH of solution A?
pH of solution A and HCl?

can someoe please help me answer this? and explain how it is done.
THANK YOU

2007-12-12 07:18:59 · 1 answers · asked by abc 1