Chemistry - October 2007

2007-10-11 01:19:14 · 8 answers · asked by Average Joes 4

Here's the equation I need help with:
Al + H2SO4 -->

Here's what I did:
Al (s) + H2SO4 (aq) --> Al2(SO4)3 (aq) + H2 (g)

Al + Hplus1 (g) --> Alplus3 (s) + H2 (g)

Is that correct? If not, what am I doing wrong?

2007-10-11 00:45:24 · 1 answers · asked by Average Joes 4

If the standard free energy change for combustion of 1 mole of a gaseous fuel is -856 kJ/mol and the number of electrons involved in the reaction is 8 mol, calculate the standard voltage that could be obtained from a fuel cell using this fuel.
Answer to 3 decimal places. Use F = 96485 C mol-1

2007-10-11 00:10:48 · 2 answers · asked by Anonymous

Calculate the reaction free energy of

H2(g) + I2(g) 2HI(g)
when the concentrations are 0.026 mol L-1 (H2), 0.33 mol L-1 (I2), and 1.84 mol L-1 (HI), and the temperature is 700K. For this reaction Kc = 54 at 700 K.

a. +11.6 kJ mol-1
b. 0 kJ mol-1
c. -11.6 kJ mol-1
d. +2273 kJ mol-1

2007-10-10 22:03:41 · 1 answers · asked by awoodifield84 1

What is the volume of 9.2 x 10^25 molecules of SbH3(g) at STP?

2007-10-10 19:58:23 · 3 answers · asked by Anonymous

1) How many grams of carbon are in 15.3 moles of tricarbon tetrahydride? (550.8 grams of C)

2) How many litres are in 0.00923 grams of O2(g)?
(6.5 x 10^-3)

3) How many moles of Br2(l) are contained in 250.0 mL of Brd(l) ? d= 0.72g/mL?
(1.13 moles of Br)

4) What is the density of NH3(g) at STP?
(0.758 g/L)

5) What is the molar mass of Al2(C2O4)3 x 4H2O?
what is the answer to this??? don't get it?

6) What is the volume of 9.2 x 10^25 molecules of SbH3(g) at STP?
I also don't get this one, please help, thanks!

2007-10-10 19:18:03 · 2 answers · asked by Anonymous

http://myspacetv.com/index.cfm?fuseaction=vids.individual&videoid=19745041

people said it doesnt but i dont have the stuff to find out for myself. will someone try it really quick?

2007-10-10 17:49:11 · 2 answers · asked by Manda K 3

Copper is extracted from the ore, Chalcopyrite, CuFeS2. How many kilograms of a 0.862% chalcopyrite ore will be necessary to produce 1.00kg of pure copper? The percentage of copper in chalcopyrite needs to be known to work this problem.

I don't know what to do with the 0.862%. Please help me.

2007-10-10 17:44:16 · 2 answers · asked by newLove 2

2007-10-10 17:32:57 · 2 answers · asked by Anonymous

A balloon was filled with 4800cm^3
the loss of hydrogen gas during filling was 20%. what mass of iron splints and 98% (by mass) H2SO4 were needed to ensure the complete filling of the balloon? assume temperature of 0 degrees C. a pressure of 1.0 atm and 100% yield.

Fe(s)+H2SO4 -----> FeSo4 (aq) + H2 (g)

how do you solve this?

2007-10-10 16:48:31 · 1 answers · asked by sexxxxxxy4u 2

"Approximately what mass of CuSO4 · 5H20 (250 g/mol) is required to prepare 250mL of 0.10 M Copper (II) Sulfate solution?"

Note: I would really appreciate it if someone could kind of, guide me through the steps, or show me the work, so that I can understand it better. I'm not able to understand that well in class, but after trying to get help on Y! Answers, I've seen that it really does help. (Thanks to the person who answered my last question, btw!)

2007-10-10 16:45:26 · 1 answers · asked by Mishal 2

the result is the emission of...
1) a beta particle 3) quantized energy
2) alpha particle 4) gamma particles

Please justify your answer, and thanks in advance.

2007-10-10 15:58:40 · 2 answers · asked by Anonymous

2007-10-10 15:58:22 · 1 answers · asked by uhmwhatever122 1

And on which solids does this not work on? What method should be used to determine their volume?

2007-10-10 15:32:32 · 1 answers · asked by Anonymous

I was wondering if evaporating or condensing a liquid is considered a chemical reaction/ chemical method?

2007-10-10 15:20:31 · 4 answers · asked by lisazhang112004 1

Write the complete and net ionic equations. Indicate the state of the reaction products.

1. Ag2SO4 (aq) + NaNO3

2. CaBr2 (aq) + Na2SO4 (aq)

3. Pb(IO3)2 (aq) + NaOH (aq)

4. K2SO4 (aq) + BaCl2 (aq)

2007-10-10 15:06:30 · 1 answers · asked by Lionheart12 5

iodine-131 is used to study the thyroid. A sample contains 20mg. 2 days later 16.85 mg are present. what is the half life of iodine-131, to the nerest thenth?

2007-10-10 15:02:14 · 1 answers · asked by Anonymous

the problem is........polycarbonate plastic ha s a density of 1.2 grams/centimeters cubed. a photo frame is construsted from two .30cm sheets of polycarbonate. each sheet measures 28 cm by 22 cm. what is the mass of the photo frame?

for mulitplying significant figures i know you have to round the answer so it has no more significant figures than are in the measurement with the fewest significant figures. i also know that the answer to the problem is supposedly 440 grams but i do not understand how to get it.

2007-10-10 14:58:56 · 2 answers · asked by highschoolmusicalfan 3

2007-10-10 14:42:05 · 3 answers · asked by stewie8675309 2

2007-10-10 14:25:18 · 5 answers · asked by massiel c 1

2007-10-10 14:15:19 · 9 answers · asked by Average Joes 4

2007-10-10 13:43:07 · 1 answers · asked by samanthaswank 1

I need this for a project, please help me.
Thank you!

2007-10-10 13:29:59 · 4 answers · asked by Ducky 2

http://tinypic.com/view.php?pic=opz6zq&s=2
Which of the following statement are true for the above Lewis structures ?

a) There are atoms in both of these structures with non-zero formal charges

b) The structures represent different compounds

c) The number of atoms S is bonded to is 4 in each structure

d) The number of atoms S is bonded to plus the number of lone pair electrons it has is equal to 4 in each structure


enter all tru statments

2007-10-10 12:51:47 · 4 answers · asked by physicsisgay 2

a mole of sodium has a mass of 23.0g
how many atoms are present in a 156g sample

so i said 156/23=6.78
6.78(6.02*10exp23)=4 081 560 atoms

i ASKED IT BEFOR THEN SOMEONE ANSWERED
"The considerations are impecable, there seems to be an error in the multiplication though. Yes, the result is 4.08 x10exp24, so there are 18 zeros missing to the right of the number you wrote."

am i right or does that guy have point

2007-10-10 12:49:33 · 2 answers · asked by Josh j 1

its for some extra credit, they'll be a few more after this! :D

2007-10-10 12:26:52 · 3 answers · asked by rawrAshleyxx 1

What is the Symbol, Atomic Number, Atomic Mass, Number of Protons and Number of neutons and electons, melting point and boiling point and normal phrase of the element aluminum.
I think I have some of the answers, I just want to check, If you don't truly want to help me dont answer.

2007-10-10 12:17:32 · 4 answers · asked by Anonymous

Ammonia nitrate+sodium hydroxide produces ammonia hydroxide and sodium nitrate

am i correct? also if im wrong can you plz correct me

2007-10-10 12:16:29 · 1 answers · asked by Anonymous

How do you determine the chemical equation of a acid?
For example nitric acid is HNO3 H2CO2 is carbonous acid.

How do you know what subscript to put? I know for a acid you always put the H and i know what the next two letters are if its nitric, carbonous ect. but what about the subscript?

Also was does the -ous and ic mean? You could have a carbonic and carbonous acid? How are they different?

Can some explain to me how this works in simple terms thanks.

Can you please use an example with sulphuric acid?

PLZ help

2007-10-10 11:58:29 · 2 answers · asked by Anonymous

A mixture of Ne and Ar gases at 353 K contains twice as many moles of Ne as of Ar and has a total mass of 47.0 g. If the density of the mixture is 4.11 g/L, what is the partial pressure (in atm) of Ne?

2007-10-10 11:51:16 · 3 answers · asked by Joe C. 1