Chemistry - December 2007

My mom has a lot of old pennies and they are hard to read because of the tarnish, anyone know an easy kitchen solution to clean them?

2007-12-03 02:53:52 · 4 answers · asked by Anonymous

2007-12-03 02:47:04 · 4 answers · asked by Anonymous

Sulfur dioxide is produced in enormous amounts for sulfuric acid production. It melts at -73°C and boils at -10°C. Its H°fus is 8.619 kJ/mol and its H°vap is 25.73 kJ/mol. The specific heat capacities of the liquid and gas are 0.995 J/g·K and 0.622 J/g·K, respectively. How much heat is required to convert 2.490 kg of solid SO2 at the melting point to a gas at 60°C?

2007-12-03 02:16:59 · 1 answers · asked by jnester0289 1

STP is used only for gases. The standard state for thermodynamic data (including individual gases) is 25C, and either 1 atm or 10^5 Pa. Ideal gas calculations at college level are done using PV = nRT

So my question is, why do we teach STP at all?

2007-12-02 23:52:41 · 2 answers · asked by Facts Matter 7

we are learning about particles; bohr's model/diagram, ions, nomenclature... Isn't 8th grade early to learn about all of that? (at the same time as balencing equations, ionic/covalent bonds etc..)

When did YOU learn those things?

2007-12-02 23:05:43 · 5 answers · asked by Zobbiezob 3

Hi,

A gas stove generates heat from the combustion of methane:

CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) ΔH = -802 kJ

How many moles of methane would need to be reacted in order to heat 4.00 kg (~ 1 gallon) of water (Cs = 4.18 J/g-K) from room temperature (25° C) to boiling (100° C)?

I know you use the formula q=c*m*deltaT. How would you go about doing it though?


Thanks!

2007-12-02 22:32:07 · 1 answers · asked by Anonymous

how many grams of O2 are consumed as 100.0 L of CH4 are burned? the volumes of CH4 and O2 are measured at 25 degrees C and .925 atm. The molar mass of O2 is 32.00 g/mol

The balanced equation is:

CH4 + 2 O2 ---> CO2 +2 H2O

2007-12-02 17:00:54 · 3 answers · asked by Anonymous

I have a all metal pot that i use to cook soups, noodles, and other things to eat on those days i don't go out. Well lately, I was boiling water with a all metal pot and neglected it, watching TV and forgetting about the bowl. Naturally, the water dried up, and the surface became completely black. I heard something about carcinogens from barbecuing with a metal rack and i was wondering now that my bowl's bottom is completely brown / black spots is it dangerous to cook and eat with it now? Or is it fine, just a side effect from the heat?

2007-12-02 16:55:39 · 2 answers · asked by Davis T 1

i know u need the the elements of fuel, o2(oxygen), and air to burn
i understand the fuel and the o2 helps fuel the fire i guess, but y air?

2007-12-02 16:49:15 · 5 answers · asked by just_kiddin_all_over_you 4

Which of the following [concerning photoelectric effect] will increase the kinetic energy of an electron ejected from a metal surface?

1) Increasing the wavelength of the light striking the surface
2) Increasing the frequency of the light striking the surface
3) Increasing the number of photons of light striking the surface

^also please explain why

2007-12-02 16:46:24 · 3 answers · asked by whatsntomake 1

STP are restored??

help please

i am so confused

2007-12-02 16:29:58 · 3 answers · asked by cc07d 1

What is the product of Pb(NO3)2 plus KI, assuming it is single replacement

2007-12-02 16:28:58 · 3 answers · asked by mashedpotatojohnson 1

in the plating reaction, copper
1. is oxidized and is the reducing agent
2. is oxidized and is the oxidizing agent
3. is reduced and is the reducing agent
4. is reduced andis the oxidizing agent

2007-12-02 16:11:35 · 2 answers · asked by titione4u 1

why would cold as opposite to warm water used t wash aspirin that is done in the experiment/lab?

can someone please help answer this question?
thankyou.

2007-12-02 13:54:33 · 3 answers · asked by abc 1

this is mole to moles
equation balanced
N2+3H2-->2NH3
if 4.0 mole of H2 rect how many moles of NH3 will be produced??
i got about 2.6mole of NH3
did i do it right please helpppp

2007-12-02 13:52:20 · 2 answers · asked by $$$$$ 2

im not sure how to figure these out can anybody help??

HClO2
HBr
HCn
sulfurous acid
hydroiodic acid
perchloric acid
phosphoric acid
hydrocloric acid
nitric acid
chlorous acid
hydrobromic acid
hypochlorous acid

if you could tell me how you got these or a method that would really help because finals are coming up soon and its 18% of my grade so please help!!!

2007-12-02 13:50:57 · 3 answers · asked by kukinney26 2

10.0
-10.0
4.0
1.0 x 10-10
-4.0

2007-12-02 13:49:54 · 2 answers · asked by sonia 1

what particular equipments can we use to measure the salt content of water in a fishpond?

2007-12-02 13:47:38 · 2 answers · asked by Anonymous

2007-12-02 13:44:25 · 4 answers · asked by liv 2

2007-12-02 13:41:04 · 2 answers · asked by Michael Barnes 1

I need the formula to convert kelvin to Celcius and kelvin to fahrenheit.

2007-12-02 13:32:52 · 2 answers · asked by rubixmaster 1

1. Ca2+, Mg2+, Fe2+
2. Mg2+, Ba2+, Ca2+, Zn2+
3. Mg2+, Fe2+, Ca2+, Cu2+
4. Ba2+, Mg2+, Cu2+

THANKS!

2007-12-02 13:31:21 · 2 answers · asked by chemquestions1 1

And CaCl2 and Cr(NO3)3?

2007-12-02 13:29:00 · 2 answers · asked by Anonymous

2007-12-02 13:27:12 · 2 answers · asked by Anonymous

help in human anatomony class

2007-12-02 13:23:57 · 2 answers · asked by gege05 1

Alright, so today, I've been learning about oxidation numbers.

I find that they are very much like naming binary compounds etc.
However, in this molecular compound, I don't see how you can make it balance out with oxidation numbers. I mean, Chlorine needs to gain 1 electron to have a full outer energy level, and Phosphorus needs 3. Also, there aren't any rules that specify like fluorine what one of the oxidation numbers must be. I am quite stumped. If any background and explanation about this topic, and this question could be provided, thanks!

2007-12-02 13:17:53 · 1 answers · asked by Anonymous

2007-12-02 13:08:01 · 1 answers · asked by blhawkhead 1

The element

2007-12-02 13:05:36 · 4 answers · asked by Anonymous

Decomposition of H2O2:
Would it be H2O2 -> H2+O2?
I think it would be that, but I recall my teacher mentioning some special rule... what would it be?

2007-12-02 12:59:49 · 4 answers · asked by YahooAnswers 2

I really don't get this one problem can anyone help?
Plz xplain ty for your help

2007-12-02 12:52:13 · 5 answers · asked by MiCk 2