Chemistry - May 2007

1...Which of the following is NOT a metallic property?
A. a hard and brittle texture
B. high density
C. the ability to be flattened and shaped
D. the ability to conduct electricity


2....Which of the following is an example of a diatomic element?
A. NaCL
B. O2
C. Mg
D. CaCl2



3....Which of the following is an example of a single-replacement reaction?
A. Fe + 2HCI -----> FeCl2 + H2
B. Mg + O2 -----> 2MgO
C. 2H2O2 ----> 2H2O + O2
D. CaCl2

2007-05-28 08:32:51 · 3 answers · asked by Anonymous

Could somebody help me develop a hypothesis on how the boiling point of a solution compares to that of pure solvent?

2007-05-28 08:32:36 · 4 answers · asked by theweirdguy1 2

0.1 M HNO2 that will be 6.5% ionized
0.1 M NH3 that will be 1.3% ionized
0.1 M NaHSO4 that will be 29% ionized

They are all weak acids/bases...please explain!

Thanks!

2007-05-28 08:27:22 · 1 answers · asked by lariru 2

I need a sample of a liquid crystal and its definition.

2007-05-28 08:23:38 · 3 answers · asked by Anonymous

I have a demonstration project I have to present, and there is not any pizzazz in it. Do you have any ideas how to spice it up? With as much pizzazz as possible? Here is the website of the experiment...

www.kidzone.ws/science/rainbow.htm

2007-05-28 08:19:53 · 1 answers · asked by yaz 2

An Atom will not normally form a chemical bond if it has_______valence electrons.

A.8
B.10
C.4
D.6

Which of the following does NOT describe how atoms can fill their outermost energy level?

A. By sharing electrons with other atoms.
B. By losing electrons to other atoms.
C. By gaining electrons from other atoms.
D. By gaining kinetic energy from other atoms.

The half-life of a radioactive atom is 2 months. If you start with a 1g of the element, how much will remain after 6 months?

A. One-half of a gram will remain
B. One-eight of a gram will remain
C. One-fourth of a gram will remain
D. None will remain

2007-05-28 07:52:49 · 5 answers · asked by Anonymous

1. An Aqueous Solution of Ethanol, C3H5OH, is 19% ethanol by mass and has a density of .9700 g ML. Calculate the molarity of the ethanol solution.

2. When a solute such as ammonium sulfate is dissolved ina solvent like water, one of the the observed effects is:
a. a decrease in vapor pressure of the solvent
b.an increase in VP of the solute
c. an increase in the melting point fo the liquid
d. a decrease in the boiling point
e. scattering of light beams by the solute particles in the soln.

3. Concerning the process/ seperation of a solid sub. into its component units where the interparticle distances are large compared to the particle sizes,
is it exothermic or endothermic and does the potential energy increase, decrease, or stay the same?

2007-05-28 07:50:52 · 1 answers · asked by julie b 1

what is a rule that describes how the equilibrium ofa system is shifted when the concentration of a substance in the reaction is increased?

2007-05-28 07:50:17 · 2 answers · asked by Anonymous

I heard that somebody told me that it causes massive gas build ups or something.

Care to explain in detail, please?

2007-05-28 07:40:29 · 14 answers · asked by Jolanda 2

the waste water is produce from cooling and washing process in rifining crude oil

2007-05-28 07:38:46 · 1 answers · asked by Eman S 1

Please refer to this link about generating the symmetry-adapted orbitals for ethylene:
http://chemistry.umeche.maine.edu/CHY556/Salcs2.html
They claim only two symmetry-adapted orbitals are possible from the combination of the carbon 2s and the hydrogen 1s orbitals. From the (S,S) carbons they add the (S,S) hydrogens to generate the sigma orbital that is bonding between C-C and bonding between C-H. From the (A,S) carbons they add the (A,S) hydrogens to get the sigma star orbital that is antibodning between C-C and antibonding between C-H. My question is that you should be able to generate two more orbitals. Why can't you subtract the (S,S) hydrogens from the (S,S) carbon to generate an orbital that is bonding between carbon and antibonding between hydrogen. Likewise, why can't you subtract the (A,S) hydrogens from the (A,S) carbons to generate an orbital that is antibonding between carbon but bonding between the hydrogens?

2007-05-28 07:14:02 · 1 answers · asked by kemmguy 2

A given compound always contains the same relative masses of its constituent elements. How is this related to the relative numbers of each kind of atom present?

help needed
thank u really much
Shawn Miller Jr.

2007-05-28 07:10:13 · 1 answers · asked by Shawn Miller 1

Which of the following aqueous solutions will have the highest freezing point temperature?

.100 molal MgBr2
.100 molal MgSO4
.150 molal KClO3
.150 molal MgCl2
.250 molal sucrose

If you could tell me why that would be helpful, too, thanks.

2007-05-28 06:40:31 · 5 answers · asked by julie b 1

2007-05-28 06:31:43 · 6 answers · asked by Anonymous

what are the chemical processes taking place in hydroelectric power??

thank you!

2007-05-28 06:29:07 · 2 answers · asked by Charles W 1

2007-05-28 06:20:57 · 3 answers · asked by vineet maurya 1

Does the freezing point of a solution remain relatively constant throughout the freezing process?

2007-05-28 06:12:16 · 4 answers · asked by theweirdguy1 2

How do i determine those things if i am given: .00135 M NAOH

Please also include the steps to do any problem of this type, so i can tell how to do others on my test tomorrow!!!

2007-05-28 06:07:47 · 6 answers · asked by Anonymous

A certain element X forms a compound with oxygen in which there are two atoms of X for every three atoms of oxygen. In this compound, 2.09 g of X are combined with 0.720 of oxygen.


Use the average atomic mass of oxygen to calculate the average atomic mass of X.

2007-05-28 05:27:30 · 1 answers · asked by Ryan C 1

Can someone explain the effects humidity levels have on hydrocarbon solvent evaporation from paint films?

2007-05-28 05:26:02 · 2 answers · asked by taulmachof 1

2007-05-28 04:57:32 · 5 answers · asked by michelle a 1

Also, why does alcohol dry faster than water? I searched on Google and Ask, to no avail TT_TT

2007-05-28 04:43:48 · 21 answers · asked by Kemis 1

2007-05-28 04:38:37 · 4 answers · asked by furquan siddique 1

it says here rather than completely evaporating the solvent, some solids can be separated from a solution by evaporating some of the solvent and then letting the solute slowly crystallise. This works because as the saturated solution cools, solute that can no longer stay dissolved crystallises. The solution is usually heated until crystals start to form and then left to cool. the crystals can be separated from the remaining solvent by filtration

2007-05-28 04:38:13 · 6 answers · asked by JennieRose 3

2007-05-28 04:36:42 · 5 answers · asked by Anonymous

The mass in grams of 1 atomic mass unit is 1.661·10-24 g. Use this value to calculate the average mass of one atom of oxygen.

2007-05-28 04:30:58 · 3 answers · asked by Ryan C 1

2007-05-28 04:14:31 · 8 answers · asked by Anonymous

the formulation of the process

2007-05-28 04:07:11 · 1 answers · asked by chindo o 1

I think it may be China but I need conformation.

2007-05-28 03:55:10 · 1 answers · asked by Blowupman 2

How do you solve this?

2007-05-28 03:51:19 · 7 answers · asked by smurf 1