Chemistry - November 2007

percentage yield

2007-11-07 08:09:56 · 2 answers · asked by Anonymous

Calculate the concentrations of Pb2+ and Cl2 at equilibrium. Ksp for PbCl2(s) is 1.6 10-5.
Pb2+ =?
Cl2=?

2007-11-07 08:07:08 · 1 answers · asked by Joshua K 1

PbI2, Ksp = 1.4 10^(-8)=?
Ag3PO4, Ksp = 1.8 10^(-18)=?
CaCO3, Ksp = 8.7 10^(-9)=?

2007-11-07 08:05:37 · 2 answers · asked by Joshua K 1

0.050 M NH3 / 0.15 M NH4Cl=?
0.50 M NH3 / 1.50 M NH4Cl=?

2007-11-07 08:04:00 · 1 answers · asked by Joshua K 1

The presence of ozone in the upper atmosphere is important because

A. O3 absorbs outgoing radiation from the earth's surface, thus helping to keep the earth warm.
B. O3 absorbs harmful solar radiation.
C. O3 dissolves in water droplets and is very reactive.
D. O3 is a major reactant in photosynthesis.

2007-11-07 07:22:42 · 5 answers · asked by Anonymous

XeF_6+ 3H_2O_---> X + 6HF

2007-11-07 07:17:49 · 2 answers · asked by Anonymous

2007-11-07 07:11:32 · 2 answers · asked by kt 2

Which of the following atoms should have a smaller second ionization energy: K or Ca?

2007-11-07 06:41:23 · 1 answers · asked by Anonymous

4Al 3O2 ---> 2Al2O3 How many moles of aluminum oxide can be formed from 5.2 moles of Al? What mass of Al is required to react with 6.00 moles of oxygen? What mass of Al oxide can be produced from 25.5 g of Al? if the actual yield is 42.5g what is % yield?

2007-11-07 06:10:40 · 5 answers · asked by Anonymous

this is for a chemistry I class at barton county community college it is due on monday november 12th 2007.

2007-11-07 06:09:45 · 1 answers · asked by jazminecrawford_1986 1

Can someone help me with this question please? im having a hard time with these types of questions

Explain why the salt of a weak acid, as well as the acid itself, must be present to form a buffer solution.

1) actually, a weak aid by itself is a buffer, no salt is needed
2) the cation from the salt is needed to partially neutralize added acid.
3) the anion from the salt is needed to partially neutralize added base.
4) the cation from the salt is needed to partially neutralize added base.
5) the anion from the salt is needed to partially neutralize added acid.

2007-11-07 06:01:15 · 1 answers · asked by Anonymous

Hi can someone help me with this question please?

We add enough base to a solution to cause the PH to increase from 7.5 to 8.5, this means that

1) OH- increases by 1 M
2) OH- increases by a factor of 8.5/7.5
3) H3O+ increases by 1 M
4) H3O+ increases by a factor of 10
5) OH- increases by a factor of 10

2007-11-07 05:51:16 · 1 answers · asked by Anonymous

2007-11-07 05:44:42 · 2 answers · asked by Anonymous

2007-11-07 05:39:26 · 1 answers · asked by gong 1

The crystal structure of an ionic compound consists of alternating cations and anions lying next to each other in three dimensions. If the cation radius is 55.9% of the anion radius and the distance between the cation nuclei is 580. pm, what are the radii of the two ions? (Note: This ionic compound is a three dimensional array. The cation to cation, center-to-center distance specified is through the center of the anion.)
anion

cation

Will give 10 points to right answer

2007-11-07 05:25:00 · 1 answers · asked by jnester0289 1

2007-11-07 04:51:01 · 1 answers · asked by Anonymous

This question was asked in the cooking section last year, but it wasn't really resolved. Last night, I was making guacamole and all I had were frozen onions and I didn't want to take the time to thaw them naturally, so I microwaved some chopped onion on a paper plate. A couple of bits started sparking and popping so much that they were a little charred. The onions were not in the microwave for long (30 seconds). Does anybody have any idea what causes this?

2007-11-07 04:38:49 · 11 answers · asked by fire_n_ice723 3

The recent hurricanes and gasoline issues are proof of the existence of a new chemical element. A major research institution has recently announced the discovery of the heaviest element yet known to science.

The new element has been named Governmentium. Governmentium (Gv) has one neutron, 25 assistant neutrons, 88 deputy neutrons, and 198 assistant deputy neutrons, giving it an atomic mass of 312. These 312 particles are held together by forces called morons, which are surrounded by vast quantities of lepton-like particles called
peons.

Since Governmentium has no electrons, it is inert; however, it can be detected, because it impedes every action with which it comes into contact. A minute amount of Governmentium can cause an action that would normally take less than a second to take over four days to complete.


Governmentium has a normal half-life of 4 years. It does not decay, but instead undergoes a reorganization in which a portion of the neutrons exchange places.

2007-11-07 03:37:56 · 4 answers · asked by Anonymous

2007-11-07 02:17:20 · 9 answers · asked by Anonymous

What volume of 6.0 M HCl would be required to dissolve 0.528g of CuO?

2007-11-07 02:02:35 · 1 answers · asked by Anonymous

1.When the dyes present in green ink are seperated by paper chromatography, the distance traveld by the water is 10cm, the distance traveld by the yellow dye is 8cm, and the distance traveld by the blue dye is 5cm. Calculate the retention factor for the blue dye.

2.Is the mass of one dozen cookies of uniform size, shape, and mass is 156 grams, calculate the mass of a single cookie.

3.calculate the volume of a marble which when place in a graduated cylinder containing 60.0 milliliters of water, raised the volume of the water to 67.0 milliliters

4.If a solid copper cube is placed in a graduated cylinder and it displaced 27.0 milliliters of water, what would be the enge lenght of the cube?

5.If a cube has an edge lenght of 2.00 centimeters and its mass is 5.00 grams, calculate its density.

6.ice has a density of 0.92 g/cm^3. what is the volume of 1.8 kilograms of ice?

2007-11-07 02:01:05 · 3 answers · asked by Anonymous

What does it mean when, in a chemical forumla, elements are written as sulfide/oxide instead of sulfur/oxygen?

2007-11-07 01:57:51 · 5 answers · asked by Caramel 2

At 500 degree celsius and 699 Torr pressure, the mass density is 3.71gdm^-3. Calculate the molecular formula of sulphur under these conditions.

Ive been trying to answer this question for ages and i cant figure out how to do it. Any help will be much appreciated.

Thank you

2007-11-07 01:47:44 · 3 answers · asked by JAGDEEP S 1

2007-11-07 01:21:21 · 1 answers · asked by tash 1

2007-11-06 23:14:06 · 8 answers · asked by Anonymous

Can I prepare 100ml of 3M sodium acetate solution by mixing 24.61g of sodium acetate anhydrous into distilled water then topped up to 100ml?

2007-11-06 19:35:59 · 3 answers · asked by pUn|sh3r 2

Deuterium(symbol D) is an isotope of hydrogen.

Which formula is incorrect for a deuterium compound?

(1) CD4
(2) C2D5OD
(3) CaOD
(4) DCl

The answer is (3)..why? Please explain..thanks.

2007-11-06 17:59:43 · 2 answers · asked by Anonymous

On complete combustion, 4.0g of a hydrocarbon give 11.0g of carbon dioxide and 9.0g of water.

What is the formula of the hydrocarbon?

(1) CH4
(2) C2H4
(3) C2H6
(4) C3H8

The answer is (1) CH4..why? I don't understand...please explain..thanks.

2007-11-06 17:49:47 · 1 answers · asked by Anonymous

Please tell me step by step nd the actual answer..thanks

Q:An antifreeze (aq) solution is 40.0% ethylene glycol (C2H602) by mass. The density of the solution is 1.05 g/cm3. Calculate the molality, molartiy, and mole fraction of the ethylene glycol.

help me~!!!

2007-11-06 17:43:29 · 1 answers · asked by Anonymous

In a mixture of Cl2 and O2 gases, the partial pressure of Cl2 is 0.200 atm. The total pressure is 0.495 atm. The temperature is 32.0oC. If the total volume of the gas mixture is 349 mL, what is the mass of O2 in grams?

2007-11-06 17:29:34 · 4 answers · asked by Anonymous