Chemistry - January 2007

Label each of the following as either a pure substance or a mixture.

A. Concrete
____________

B. water
____________

C. oxygen
____________

D. air
____________

2007-01-25 12:13:21 · 11 answers · asked by Anonymous

can explain the difference between physical and chemical properties

2007-01-25 11:48:05 · 6 answers · asked by linda48217 2

I can't seem to find this in any of the texts or sites I'm using.
Please, I don't want any quick/simple answers (I'm not a cheater). Can someone push me toward the right answer? (this is a question for a class friday morning...)

2007-01-25 11:43:52 · 8 answers · asked by creative writer 3

2007-01-25 11:32:58 · 1 answers · asked by Anonymous

The copper coin was in a evaporating dish containing zinc metal, tunred gray and then was heated in a busen burner.

2007-01-25 11:32:38 · 3 answers · asked by ? 2

My science fair project is "what is the effect of different contaminants on the rate of rusting" in this expiriment, i used 4 different liquids, placed a small iron nail in each one, and determined which nail rusted the fastest and WHY. well i got my results. salt water was the fastest [WHY?] vinegar turned the nail black [WHYYY?] and lemon juice and orange juice didnt really have an effect of rust on the nails. [why???] i want to know why saltwater rusts fastest, why vinegar does what it did, and why orange juice and lemon juice did what it did. my science fair project is due on monday. PLEASE HELP ): ByTheWay: the nails were in the liquids for a period of 3 weeks.

HELP ME PLEASEE ! <3

2007-01-25 11:13:11 · 4 answers · asked by priyankaaaaa 2

in chemical reactions between an enzyme and a ligand ,what does it indicate -in terms of affinity -that a substance has a high dissociation constant while another has a lower one ? plz help me in this so as to be able to interpret data in my chemistry report.

2007-01-25 11:13:08 · 1 answers · asked by Ahmed S 1

someone told me not to watch magnesium burn but i did from like 4 feet away for about 3 seconds. it was just a thin strip of magnesium from my chem lab and ever since my eyes have seen sub par. nothin that unusual but things i used to see clearly i now need to squint for. its not that bad that i need glasses but its definitly noticable to me. any information on this subject as to how it can affect your eyes or what kind of light it sheds would be a big help

2007-01-25 11:06:41 · 3 answers · asked by 12345 2

2007-01-25 10:58:13 · 1 answers · asked by alanis118 1

2007-01-25 10:40:57 · 1 answers · asked by SOUND OF TRUTH 1

I had asked a similar question about a month ago but forgot to include in my details how much red iodine I had. White iodine is not available in Canada and I cannot find a pharmacist who will do compounding (rather frustrating I might add). In my other question, I was told that peroxide would turn red iodine clear so now I would like to know what amount of peroxide to use. Thanks for your time. Take care.

2007-01-25 10:35:58 · 3 answers · asked by love,peace&happiness 1

what is the difference in the result we get from native and sds page.

thanks

2007-01-25 10:22:03 · 3 answers · asked by SOUND OF TRUTH 1

2007-01-25 10:17:09 · 7 answers · asked by Daniel w 2

2007-01-25 10:12:04 · 7 answers · asked by Anonymous

First of All, could someone explain what synthsis, decomposition, and single replacement mean?
And heres four equations im having trouble balancing and identifying the category of reaction.
____Zn(s)+______HCl(aq) => __ ____+___ ________
_______Mg+____H3PO4 =>____ _________+__ ______
_____Al2O3(s) =>___________Al(s)+___ __________
KClO3(s) => _______O2(g)+______ _________

could you please help me how to do this,, please i need to study for the exam

Please explain it to me as i was a retard

2007-01-25 09:56:24 · 4 answers · asked by Ballerina 5

please i am so confused about it

2007-01-25 09:49:50 · 2 answers · asked by lilbutterfly555 1

How was it formed?(What chemical elements make it up?) What are common uses of it?What is the rarity of it? i need anything i can get in a 30 minute span. HURRY!

2007-01-25 09:32:17 · 3 answers · asked by Christian N 1

2007-01-25 09:20:07 · 1 answers · asked by sylee 1

How does it make things white, and how does it kill germs?

Don't be afraid of being scientific in your answer.

I've done my fair share of chemistry but I can't remember anything about bleach, besides something to do with Chlorine ions.

*BONUS QUESTION*: Do you like the smell of bleach? (some people do; I'm undecided)
[WARNING: SOLVENT ABUSE CAN KILL INSTANTLY!]

2007-01-25 09:18:15 · 6 answers · asked by Neil_R 3

What are the names of the elements that are in platinum's family? I am doing a project and i need to know!! please get back to me! Thanks!

2007-01-25 09:15:41 · 3 answers · asked by Abbey C 1

2007-01-25 09:14:27 · 1 answers · asked by Grace J 1

nickle,silver,carbon or copper?

2007-01-25 08:56:19 · 10 answers · asked by christine v 2

2007-01-25 08:51:36 · 8 answers · asked by Anonymous

whats so imporANT BOUT IT

2007-01-25 08:49:52 · 5 answers · asked by Anonymous

Also besides the unt of Liter being recognized as L...what other unit is liter defined by? m^3, cm^3,g^3,c^3?

2007-01-25 08:49:17 · 2 answers · asked by D M 1

2007-01-25 08:48:44 · 1 answers · asked by Anonymous

I am a replacement maths/physics/chem teacher, kids from 10 to 16. To get their interest, I make small experiements with "effects".
I am looking for a mixture/experiement that would produce some coloured smoke that would be opaque and abundant enough to be well visible, dissipate rapidely and ESSENTIALLY, harmless!
(making chlorine is easy and nice, but won't do!)
Maybe the formula to make the (white) fumigenes used on stages in concerts?

2007-01-25 08:46:30 · 2 answers · asked by just "JR" 7

Can someone please help me, i have my answers and i just want to double chack, thanks !!

2. What are the correct formulas of the product for this reaction:
BaCl2 + K2(CO3)

a. Ba(CO3) + K2CL
b.Ba2(CO3) + KCL
c.Ba(CO3) + KCl
d.Ba2(CO3)3 + KCL

3. What is the classification for this unbalanced reaction?
Fe + HCl -> FeCl3 + H2
a.decomposition
b.combustion
c.double replacement
d.combination
e.single replacement

6. What equation is balanced for the following reaction?
HF + SiO -> SiF + H2O

a. 4HF + SiO -> SiF4 +H2O
b. 8HF + 2 SiO2 -> 2SiF + 4H2O
c. 2HF + SiO2 -> SiF4 +H2O
d. 4HF +SiO2 -> SiF4 + 2H2O

7. Which equation is balanced for the following reaction?
Al + H2O -> Al2O3 +H2
a. 2AL + 3H2O -> Al2O3 + 3H2
b. 2Al +3H2O -> Al2O3 +H2
c. Al + H2O -> Al2O3 +H2
d. 2Al + H2O -> Al2O3 +H2

thanks!

2007-01-25 08:33:42 · 2 answers · asked by nice too meet you. 4

2007-01-25 08:17:23 · 5 answers · asked by chet4pizza 1

2007-01-25 08:16:45 · 4 answers · asked by chet4pizza 1