Chemistry - November 2007

what are some things that have at least of these elements in them Lithium, sodium, potassium, rubiduim, cesium, and francium we have like 5 things already but we need 20 things and we are just having a hard time with this

2007-11-09 08:20:16 · 1 answers · asked by saintsrox 1

you know, i mean which kind of surfactant, the amount of it, and so forth,

i appreciate any help. thanks

2007-11-09 08:11:44 · 1 answers · asked by twank1000o 2

What is the balanced equation for the reaction of a Group 2A(2) oxide with water?

2007-11-09 06:59:24 · 3 answers · asked by xxiangel 2

Seems easy, but I frogot how to... Thanks!

2007-11-09 06:57:40 · 3 answers · asked by chemquestions1 1

covalent bond Explain Electronegativity? What is the difference between a polar covalent bond and a nonpolar?

2007-11-09 05:34:23 · 4 answers · asked by Anonymous

q and w for the following exothermic process at P = 1 atm and T = 370 degrees kelvin?

a) q and w are negative

b) q is negative, w is positive

c) q is positive, w is negative

d) q = 0, an adiabatic process

e) q and w are both positive

2007-11-09 05:09:32 · 1 answers · asked by 41 1

2007-11-09 05:04:18 · 4 answers · asked by twizzlas 2

50 cm^3 of ethene gas diffused through a porous pot in 30 seconds at room temperature. How long will 25 cm^3 of nitrogen take to diffuse through the pot at 60 °C ?

(1) 20 s
(2) 30 s
(3) 40 s
(4) 50 s

The answer is (1) 20 s...I don't understand...please show me your workings and explain..thanks lots

2007-11-09 02:19:36 · 1 answers · asked by Anonymous

2007-11-09 01:56:16 · 1 answers · asked by Anonymous

Disccuss the advantages and disadvantages of optical density as method of determination of biomass concentration

2007-11-09 00:07:14 · 1 answers · asked by leo 2

(a) How many grams of acetic acid are, contained in 24.0
g of vinegar? .
(b) How many pounds of acetic acid are c.ontained in
24.0 pounds .of vinegar?
(c) How many grams of sodium chloride, NaCI, are
contained in 24.0 g .of saline solution that is 5.0%
NaCI by mass?

2007-11-09 00:06:45 · 1 answers · asked by mohamed r 1

2007-11-08 23:40:39 · 1 answers · asked by shiyas932511 1

Ba(OH)2 + H3PO4 = Ba3(PO4)2 + H2O When I balance it, I get .....

3Ba(OH)2 + 2H3PO4 = Ba3(PO4)2 + 6H2O ........but what about the net ionic reaction.......for some reason , I dont think there was one, because they both remained aq.

2007-11-08 22:47:24 · 3 answers · asked by dannchris@sbcglobal.net 1

Just the positive, just the negative, or a combination?
Please help!

2007-11-08 22:45:58 · 2 answers · asked by Eponine 2

... How do I best go about obtaining some? I just need a small quantity for electroplating -- maybe a pound in powder form. Anybody out there can help me out? It'd be greatly appreciated after all the dead-ends and run-around I've dealt with lately. Thanks!

2007-11-08 22:19:59 · 5 answers · asked by SKVY 4

Oxygen atoms can combine with ozone to form oxygen.
O3(g) + O(g) -> 2 O2(g)
(delta)H°rxn = -394 kJ

(a) Using (delta)H°rxn and the bond energy data in Table 1, estimate the bond energy for the oxygen-oxygen bond in ozone, O3. _____kJ/mol

(b) How does your estimate compare with the energies of an O-O single bond and an O=O double bond? Explain

(c) Does the oxygen-oxygen bond energy in ozone correlate with its bond order? (yes/no)

Table 1 : http://www.webassign.net/kt/9-10tab.gif

2007-11-08 21:13:07 · 2 answers · asked by beeboroachgoingon197 1

I would like to know whether sodium phosphate dibasic NA2HPO4, 5 x 0.1M in 500ml water, prepared using 35.5g diluted in 500ml distilled water, will form crystals when stored at -4 degree celsius? I'm wondering why the one prepared by my senior forms crystals whereas mine don't. I've followed her instructions carefully. What seems to be the problem?

2007-11-08 20:06:45 · 1 answers · asked by pUn|sh3r 2

hey thnks for answering my qns.(how to draw the molecular orbital diagram for BeF2)
but i wanted a MO diagram. u gave me the lewis structure instead.

2007-11-08 19:20:10 · 1 answers · asked by garwood_lim 1

Reaction (1) to (4) can occur in the industrial conversion of ammonia into nitric acid.

Note: I would denote the oxidation number as ON:

Which one of these reactions shows the greatest change in the oxidation number of nitrogen?

(1) 4NH3 + 5O2 ---> 4NO + 6H2O
The ON of N in 4NH3 is -3, and the N in 4NO is +2, correct?

(2) 3NO2 + H2O ---> 2HNO3 + NO
The ON of N in 3NO2 is +4, the ON of N in 2HNO3 is +6 and the ON of N in NO is +2, correct?

(3) 2NO + O2 --> 2NO2
The ON of N in 2NO is +2 and the ON of N in 2NO2 is +4, correct?

(4) 4NH3 + 6NO --> 5N2 + 6H2O
The ON of N in 4NH3 is -3, the ON of N in 6NO is +2 and the ON of N in 5N2 is 0, correct?

however, my answer is (2) but the correct answer is (1)...please correct my mistakes from the above workings and show me your workings on how you calculate out that the greatest change in the oxidation number of nitrogen is in (1)..thanks

2007-11-08 16:41:29 · 1 answers · asked by Anonymous

Iron ores contain oxides such as iron(3) oxides (Fe2O3). IN a blast furnace, the iron ore is made into iron metal by heating it with carbon monoxide. Carbon Dioxide is the toher product. Write a balanced equation for this reaction. How much carbon monoxide is required to produce 504 gram of iron metal.( step by step guide please)

2007-11-08 16:35:20 · 2 answers · asked by Black Ninja12 3

2007-11-08 16:29:45 · 1 answers · asked by Maureen T 1

a) the internal energy of a system increases when work is done on the system and heat is flowing into the system

b) the internal energy of a system increases when more work is done by the system than heat was flowing into the system

c) the system does work on the surrounding when an ideal gas compresses against a constant external pressure

d) the enthalpy of a system decreases when work is done on the system and heat is flowing into the system

e) the enthalpy of a system increases when more work is done by the system than heat was flowing into the system

2007-11-08 16:24:24 · 1 answers · asked by 41 1

The specific question given was:
Use the photoelectric effect to explain the emergence of the quantum theory. How did this concept eventually lead to the wave-particle duality of matter?
Please help me with any answers you have!
Thanks :)

2007-11-08 15:59:05 · 2 answers · asked by Leslie 2

I had a doubt regarding the fireworks....

Do chemical contents of these any Fireworks/Crackers contain Nitrogen/Phosphorus /Potassium(NPK) elements/oxides which may serve Fertilizers for plants?

Is it safe to put firework chemical powder content in Plants soil?

2007-11-08 15:50:09 · 2 answers · asked by Anonymous

a) For a liquid to have a vapor pressure, rate of condensation must be greater than rate of evaporation.

b) Substances with large molar masses have relatively low vapor pressures.

c) An increase in temperature will increase the vapor pressure of a liquid

d) Temperature changes during a phase change.

e) For ice to float in water, it's density must be less than that of water.

2007-11-08 15:47:10 · 3 answers · asked by Anonymous

I'm trying to find the pH of HONH3Cl. I have .400 M and I know that it becomes:

HONH3Cl <-> NH2OH + HCl

I also know how to do an IRE (also called ICE) table, but what value do you use for Kb for the above reaction? or do you?

2007-11-08 15:40:47 · 2 answers · asked by xxsoccerchickxx_84 1

Find the solubility of AgI in 2.8 M NH3 [Ksp of AgI = 8.3 *10-17 and Kf of Ag(NH3)2+ = 1.7 * 107].

2007-11-08 15:36:52 · 1 answers · asked by socr8711 2

How much heat (kJ) is required to completely melt 30.5 grams of ice at 0 oC ?

anddddd

Which of the following are true statements ?



a) The triple point of H2O is -4oC and 4.58 atm

b) At 5 atm and −78oC solid CO2 will not sublime

c) The freezing temperature of a substance is less dependent on pressure than is its boiling boint

d) At 20 atm and −78oC CO2 is in the liquid phase

2007-11-08 15:29:05 · 4 answers · asked by matt b 1

A mixture of 10 cm^3 of methane and 10 cm^3 of ethane was mixed with an excess of oxygen and the mixture was ignited. After cooling to room temperature, the residual gas was passed through a solution of potassium hydroxide. What was the volume of the gas absorbed by the alkali?

(1) 15 cm^3
(2) 20 cm^3
(3) 25 cm^3
(4) 30 cm^3

The answer is (4) 30 cm^3...I don't understand...Can you show me the workings and with explanation too? Thanks a lot.

2007-11-08 15:24:09 · 3 answers · asked by ♪£yricảl♪ 4

The relative atomic mass of an element with atomic number 10 is 20.2. The element consists of two isotopes, the nuclei of which contain 10 and 12 neutrons respectively. The ratio of the relative abundance of the lighter to heavier atoms is ______

(1) 1 : 9
(2) 9 : 1
(3) 1 : 4
(4) 4 : 1

The answer is (2) 9 : 1... i don't understand...please show me your workings.. and explain too..thanks.

2007-11-08 15:19:09 · 2 answers · asked by Anonymous