Chemistry - December 2007

for science mid term tommorow

2007-12-11 23:11:54 · 1 answers · asked by Anonymous

why do balloons expand when it is exposed to hot air and why do balloons shrink when it is exposed to cold air

2007-12-11 22:59:21 · 4 answers · asked by Anonymous

Thanks to those of you who replied to my first question. As there appears to be more than one answer, I'll clarify a little. The HCl was ordered by a colleague. I wanted 0.1M bench acid for school use but he ordered a litre of 35% HCl (That's what it says on the bottle). As a biologist who's too lazy to work out the molarity based on the molecular mass of HCl, I thought I'd ask you kind people... So am I right in thinking that it's around 10-12molar? That's a lot of dilution for me to do! I thought it was strong when I opened the bottle and chlorine gas appeared!

2007-12-11 21:59:15 · 3 answers · asked by MyOrchid 1

2007-12-11 21:51:14 · 3 answers · asked by mr e 1

1). Determine ∆H˚ for the reaction

Zn(solid) + 2H^+(aqueous) -----> Zn^2+(aqueous) + H2(subscript)(gas)

2) From the following equations and enthalphy change:

a) (∆H˚ rxn= -393.585) C(graphite) + O2(subscript)(gas) -----> CO2(subscript)(gas)

b) (∆H˚ rxn= -2858) H2(subscript)(gas) + ½O2(subscript)(gas) -----> H20(subscript is 2)(liquid

c) (∆H˚ rxn= -2598.8) 2C2H2(subscript are 2nd and 3rd "2")(gas)+5O2(subscript)(gas) -----> 4CO2(subscript)(gas) + 2H2O(subscript is 2nd "2")(liquid)


3) Calculate the ∆H˚ of C2H2(subscript is 2) from its 2C(graphite) + H2(subscript)(gas) -----> C2H2 (subscript is 2)(gas)

2007-12-11 21:21:20 · 1 answers · asked by Janiper 1

Is this possible to identify pure gold? or is there any sound test?

2007-12-11 20:20:28 · 2 answers · asked by Devoted 1

any acronyms or something

2007-12-11 20:15:47 · 3 answers · asked by biomes 1

2007-12-11 18:53:17 · 8 answers · asked by bhudz 1

Use the reaction: () are subscripts
2Fe(2)O3 + 3C -> 4Fe + 3CO(2)


Using 1000g C, how many grams of Fe can be produced?

What is the theoretical yield of Fe in a reaction with 7.00g Fe(2)O(3) and 1.25g C?

What amount of the reactant in excess will remain at the end of the reaction? Give answer in grams.

2007-12-11 17:59:24 · 4 answers · asked by Anonymous

2007-12-11 17:35:45 · 8 answers · asked by Anonymous

list that has the formula, picture of the formula from 1 to 10, that is all, much appreciated

2007-12-11 16:06:42 · 2 answers · asked by thewillprince 2

2007-12-11 15:40:10 · 3 answers · asked by dshariff 1

2007-12-11 15:23:31 · 1 answers · asked by Anonymous

33.6 L of CH4 are combusted under a dish containing ice. change in Hrxn for the combustion of CH4 is -802kJ/mol. How many grams of ice can you melt if none of the heat is lost to the environment? (change Hfus=6.00 kJ/mol)

is this how u do it? can u do it for me?

Calculate how many moles are in 33.6 L.

Moles X 802kJ/mol = total heat.

Total heat / 6.00 kJ/mol = moles of ice

moles of ice X mol wt. of ice = grams of ice melted

2007-12-11 15:23:17 · 2 answers · asked by Anonymous

2007-12-11 15:20:03 · 2 answers · asked by Anonymous

2007-12-11 15:18:27 · 6 answers · asked by Anonymous

2007-12-11 15:07:06 · 2 answers · asked by Anonymous

give examples

2007-12-11 15:02:09 · 4 answers · asked by lucy 1

water sources: lakes, tap water, rain water, ocean, pond, etc.

2007-12-11 14:56:02 · 5 answers · asked by Abby! 4

Solid copper is added to nitric acid, and copper(II) nitrate, nitrogen dioxide, and water are produced.

What's the balanced equation for this?

The skeleton equation would be like;;

Cu + HNO3 yields to CU(NO3)3 + NO2 +H2O

The numbers are subscript, of course.

2007-12-11 14:47:30 · 4 answers · asked by Anonymous

if your answer is an ester, then could you please tell me what an ester is

2007-12-11 14:39:58 · 3 answers · asked by Anonymous

I know that it dissolves in HCl so that would make it polar right?

2007-12-11 14:30:38 · 4 answers · asked by Anonymous

Which of the following are properties of carbon ( choose all that apply ):

a. each of its atoms needs to make four bonds
b. it is found in all proteins
c. it can bond with other elements and form long chains
d. it is in a water molecule

2007-12-11 14:30:32 · 3 answers · asked by tinkgurl213 2

1) HCl + Na4Cl =
2)HCl + KIO3 =
3)H2SO4 + HNO3 =
4)H2SO4 + Na2SO3 =
5)H2SO4 + NH4Cl =
6)H2SO4 + KIO3 =
7)H2SO4 + BaCl2 =
8)Na2SO3 + HNO3 =
9)NH4Cl + HNO3 =
10)KIO3 + HNO3=
11)BaCl2 + HNO3 =
12)Na2SO3 + NH4Cl =
13)Na2SO3 + KIO3 =
14)Na2SO3 + BaCl2=
15)KIO3 + BaCl2=
Any of these are greatly appreciated... Thank You.

2007-12-11 14:08:36 · 2 answers · asked by Anonymous

I hate chem because it is hard to visualize and i am terrible at word problems. Also there is tons of things you need to know and memorize in order to have a good foundation for later topics.

Is there any book or anything that makes chem more fun to learn? any ideas?? or how do you approach learning chem?

2007-12-11 14:08:16 · 5 answers · asked by Someguy25 4

What is the value of c in a vacuum? Give the numerical value as well as the definition.

2007-12-11 13:56:46 · 3 answers · asked by Anonymous

My mom was at her work and herd an explosion in the office, she said it almost sounded like a gunshot. They went into the kitchen and found two 2L bottles of soda on the floor, one bottle exploded and the bottom part of the bottle was jagged and 2/3 of the bottle looked melted as if it had been lit on fire; the other bottle had exploded just below the neck of the bottle.
The reminants of the soda smelt like spoiled grapefruit juice (very acidic). Nobody was in the room, and it seems that it was a case of SBC (Spontaneous Bottle Combustion). Can anybody explain this?????

2007-12-11 13:48:15 · 7 answers · asked by rog_roz14 2

2007-12-11 13:47:49 · 4 answers · asked by ruby 2

my science teacher said it, but I did not write it down, because I wasn't thinking. Something about sugar, food coloring and some other things. I forgot. Please help me.

2007-12-11 13:42:52 · 1 answers · asked by Anonymous

2007-12-11 13:41:30 · 3 answers · asked by Anonymous