Chemistry - January 2007

a) breath fogging a mirror
b) bleaching a stain
c)milk souring

2007-01-27 12:43:54 · 9 answers · asked by happy days 1

i ned help with this problem:

C.E Bemis and colleagues at oak ridge national laboratory confirmed the synthesis of element 104, the half-life was only 4.5 s. Only 3000 atoms of the element were created in the tests. How many atoms were left after 4.5 s?

2007-01-27 12:34:42 · 2 answers · asked by Mia16 3

2007-01-27 12:26:34 · 1 answers · asked by n 1

Based ONLY on molecular structure (no pH, no info provided) AND when it's a huge molecule, I'm not talking NaOH, I'm talking BIG crazy scary drug molecules

2007-01-27 12:25:38 · 2 answers · asked by fingerseven11 1

please put in scientific notation thank you so much

2007-01-27 12:24:09 · 4 answers · asked by n 1

One molecule of a compound weighs 2.03 x 10-22 g. Its molar mass is:
a.48.0 g/mol
b.92.1 g/mol
c.114 g/mol
d.122 g/mol
e. None of the above

2007-01-27 12:11:08 · 3 answers · asked by Anonymous

What is the difference between variables being directly proportional or inversely proportional?

2007-01-27 12:08:05 · 1 answers · asked by untilyoucamealong04 3

How is gold disposed of at the end of its usual life?

2007-01-27 12:04:16 · 12 answers · asked by shagrif2003 1

Naturally occuring carbon consists of two isotopes carbon-12 and carbon-14. What are the percent abundances of the two isotopes in a sample of carbon whose atomic mass is 12.011 amu?

2007-01-27 11:55:54 · 1 answers · asked by untilyoucamealong04 3

2007-01-27 11:41:12 · 2 answers · asked by Anonymous

2007-01-27 11:38:17 · 1 answers · asked by stevovanzant 1

An unknown metal requires 34.7 J to heat a 23.4 g sample of it from 24.3 degrees C to 28.9 degrees C.

2007-01-27 11:36:28 · 2 answers · asked by Anonymous

You hold a gram of copper in one hand and a gram of aluminum in the other. Each metal was originally at 0oC. (Both metals are in the shape of a little ball that fits into your hand.) If they both take up heat at the same rate, which will warm to your body temperature first?

2007-01-27 11:31:28 · 9 answers · asked by Anonymous

it has seven letters

2007-01-27 11:14:59 · 6 answers · asked by BethB 2

I have chemistry homework problems that i need help with. if you can help with explaining the answers too that would be so much help so i can actually understand this!
1. Is the following reaction and ocidation reaction or reduction reaction?
Ni(s)-->Ni^2+(aq)+ 2e-

2. Chemical properties of hydrogen compounds can have vast differences depending on the state of matter (solid, liquid or gas). The difference in chemical properties is related to

a.the dissociation of H+ from the hydrogen compound into solution.
b.the dissociation of OH- from the hydrogen compound into solution.
c.the energy threshold required to break the covalent bonds in the solid.
d.the slight cohesion of the liquid solvent forming the aqueous solution.

3. Choose the word that best completes the following statement. In a neutralization reaction an acid and base react to form water and ____.
a.salt b.metal c.ionic compound d. ester

2007-01-27 11:10:15 · 2 answers · asked by nice too meet you. 4

i need all info on agarose electrophoresis.pls help

2007-01-27 10:49:13 · 1 answers · asked by Anonymous

2H2(g) + O2(g) --> 2H2O(g) ΔH = −486.6kJ


Which of the following are true statements for the above chemical reaction ?


a) A phase change is involved


b) Two moles of hydrogen gas react with two moles of oxygen gas to
produce two moles of water vapor


c) Energy is absorbed by the system, the reaction species


d) If the reaction takes place at constant pressure, q = −483.6 kJ


e) ΔH for reacting four moles of hydrogen gas with two moles of
of oxygen gas is −977.2 kJ

2007-01-27 10:42:14 · 1 answers · asked by MARK 2

I want a site that draw the chemical formula for a compound of my choice, and perhapes also have a simple interface.

2007-01-27 10:32:32 · 2 answers · asked by Mohamed K 2

in the movie kingkong what is the things related to chemistry?explain why?

2007-01-27 10:02:11 · 2 answers · asked by eryll 1

What is the H+ ion concentration of an aqueous solution that has a pH of 11? And why?

2007-01-27 09:13:09 · 1 answers · asked by untilyoucamealong04 3

2007-01-27 09:12:01 · 7 answers · asked by Anonymous

2007-01-27 08:58:10 · 6 answers · asked by larry.benoit 1

2007-01-27 08:34:14 · 1 answers · asked by Anonymous

2H2(g) + O2(g) --> 2H2O(g) ΔH = −486.6kJ



Which of the following are true statements for the above chemical reaction ?



a) A phase change is involved


b) Two moles of hydrogen gas react with two moles of oxygen gas to
produce two moles of water vapor


c) Energy is given off to the surroundings


d) If the reaction takes place at constant volume, q and ΔH must by definition have the same value


e) ΔH for reacting four moles of hydrogen gas with two moles of
of oxygen gas is −977.2 kJ

2007-01-27 08:31:08 · 1 answers · asked by Christie 1

2007-01-27 08:22:35 · 5 answers · asked by Anonymous

How much heat (kJ) must be removed in order to change 3.11 moles of water at 41.0 oC to ice at -24.0 oC ?

The specific heat capacity of solid water is 2.03 J g-1 oC -1

Use a negative sign in your answer if heat is removed.

2007-01-27 08:10:19 · 4 answers · asked by purple222 2

Hi, can anybody tell me if i did this correctly?

Name the following coordination compound:
[Mo(H2O)6]Br3

Is the answer: Hexaaquomolybdenum bromide

2007-01-27 08:03:02 · 1 answers · asked by Hello 1

Can you use peroxide to clean pennies?

2007-01-27 07:52:10 · 4 answers · asked by Tony A P 1

strange sensations

2007-01-27 07:01:54 · 2 answers · asked by Anonymous

3.09474 KJ of energy is gained/lost by 236.0 ml of water containing 4.08 g of dissolved MgSO4, according to the equation,

MgSO4 → Mg2+(aq) + SO42−(aq).

The change in enthalpy must be −91.3 kJ/mol. What is the change in temperature ( oC ) for the above process assuming no heat is lost or gained by the surroundings ?

2007-01-27 06:51:31 · 1 answers · asked by MARK 2