Chemistry - April 2007

Which Is A Not A type of matter

semi solids,solids.gases,liquids

2007-04-27 17:26:25 · 7 answers · asked by LaKesha 1

Many metals need to be purified after mining. One example is vanadium which is commonly found in its natural form, vanadium oxide (V2O5), when extracted from the Earth. One step in the production of pure vanadium metal uses the reaction of vanadium oxide with an excess of aluminum metal at high temperature to give pure vanadium metal and aluminum oxide. In a test run, 36.1 kg of pure vanadium metal is isolated when 76.2 kg of V2O5 reacts. Calculate the percent yield of vanadium.

2007-04-27 17:11:51 · 2 answers · asked by ♥ReKa♥ 2

2007-04-27 16:48:33 · 3 answers · asked by edgabemadrigal 1

A compund is 42.4% C, 2.4% H, 16.6% N, and 37.8% O by mass. The addition of 6.45 g of this compound to 50.0 mL benzene, C(6)H(6) [Density=0.879 g/cm cubed], lowers the freezing point from 5.53 to 1.37 degrees Celsius. What is the molecular formula of this compound? Show work, and provide a balanced equation.

2007-04-27 16:47:06 · 2 answers · asked by thekrimson 1

red tailed hawk
golden crowned kinglet
pine borer
pine
salamander
snake
mouse
oak acorns
oak tree
bacteria
fungi

2007-04-27 16:09:49 · 1 answers · asked by the jailer777 2

This was on our chem final today and I'm wondering if I guessed correctly. I thought: Fe(sub)2O(sub)3

right??

2007-04-27 15:43:34 · 7 answers · asked by Anonymous

2007-04-27 15:37:32 · 2 answers · asked by TPatel 1

I need to know what produces heat when mixed with cO^2 for a great way to efficiently heat houses.

2007-04-27 15:34:04 · 1 answers · asked by Codster 4

dear all, I see people use centrifugal decanter to separate mixture of liquid and solid, after that, liquid is transfered to membrane to separate liquid mixture.
But I consider that Can we use both centrifugal decanter and membrane to separate azeotropic mixture of liquid such as ethanol anf water to increas capacity as well as reduce time to dehydrate this azeotropic mixture ?
It mean that we will install membrane in centrifugal decanter...
Thanks

2007-04-27 15:31:34 · 3 answers · asked by Anonymous

I know that the pH does affect the answer but im just not sure of the equation!

2007-04-27 15:08:48 · 1 answers · asked by Anonymous

At 298 K, a cell reaction exhibits a standard emf of 0.21 V. The equilibrium constant for the reaction is 1.31 X 107. What is the value of n for the cell reaction?

2007-04-27 14:47:23 · 1 answers · asked by Justin T 1

C can make pi-bonds to O, but Si cannot.
Si can use d-orbitals to bond to O, but C cannot.
Si is more electronegative than C.
The C-O bond is more polar than the Si-O bond.
All of the above

2007-04-27 14:37:15 · 1 answers · asked by Justin T 1

How many d-electrons are associated with the central metal ion in the complex: K3[V(C2O4)3]

2007-04-27 14:30:52 · 1 answers · asked by Anonymous

The Ka for hydrocyanic acid (HCN) is 4.9 X 10-10. What is [OH-] in a 0.35 M solution of sodium cyanide (NaCN)?

heres how i approached

x^2/.35=4.9*10^-10

x=1.31*10^-5

pH= -log(answer)
pH=4.88

pOH=14-4.88
pOH=9.12

[OH]= 10^-9.12

im doing something wrong.

2007-04-27 14:10:37 · 2 answers · asked by Anonymous

also what mass of lithium carbonate, Li2CO3 is produced?

need a lil help im lost as lost can be lol

2007-04-27 13:44:14 · 3 answers · asked by mrchrister93023 1

DHA (docosahexanoic acid) is a polyunsaturated fatty acid
that is believed to: (choose all that apply)

1) lower LDL cholesterol
2) be replaced in brain cell membranes by ingested trans fatty acids
3) only be available from foods like fish
4) reverse neurodegenerative disorders like Alzheimer's
5) be produced from omega-3 and omega-6 fatty acids
6) be involved in brain and eye development
7) be necessary in brain cell membranes

2007-04-27 13:11:25 · 2 answers · asked by Shay W 1

I'm writing a short story about a hoax, and I need the police in the story to be put off the track for awhile by making fake blood taste like real blood. Real blood has a unique metallic taste. (You know how a cop sometimes dips a finger into a pool of what looks like blood to taste it?)

2007-04-27 12:58:35 · 5 answers · asked by TitoBob 7

if it contained hydrolyzed aspartame

2007-04-27 12:23:56 · 3 answers · asked by ash1eyro 1

2007-04-27 11:52:05 · 5 answers · asked by cbz 1

for the reaction

2 HCl + Na2CO3 -> 2 NaCL + H2O + CO2

8 moles of CO2 is collected at STP. what is the volume of CO2?

Please explain how you got the answer

2007-04-27 11:41:52 · 1 answers · asked by cbz 1

Of the compounds NaOH, CuS, and NaNO3, which one is appropriate to use in a salt bridge? Briefly explain your answer, and for each of the other comounds, include a reason why it is not appropriate.

Okay, so I said that NaNO3 is appropriate to use as a salt bridge, because it is an electrolyte solution whose ions will not react with other ions in the cell. Is this right?
I don't know why the other ones wouldn't be appropriate, though.

2007-04-27 10:48:19 · 1 answers · asked by delilah 2

2007-04-27 09:51:38 · 3 answers · asked by Anonymous

1) On going from left to right in a periodic valence of elements?..... ......2) on going down in a group, chemical reactivity of metals?...... .......3)On going down in a group of non-metal chemical reactivity of elements?............. 4)Modern periodic table was presented by?............... for q's 1-3 just say increase or decrease or remain the same........... for q #4 choose from Mendeleev Rutherford Moseley Bohr

2007-04-27 09:43:37 · 1 answers · asked by Anonymous

1) If a 17.0-g sample of impure nickel metal reacts with excess CO at 0 °C and 1 atm to form 6.25 L of
Ni(CO)4 gas, what is the percent of nickel in the sample?

2) Which molecule contains polar bonds but is nonpolar? Why?
a) SCl2
b) OF2
c) SiCl4
d) NCl3
e) SO2

3)An aqueous solution of glycerol, C3H8O3, is 48% glycerol by mass and has a density of 1.120 g/mL.
Calculate the molality (m) of the glycerol solution.

I just can't figure these ones out. I'd appreciate any help. Thanks.

2007-04-27 09:41:51 · 1 answers · asked by Hilary R 1

where is it used?

2007-04-27 09:40:22 · 5 answers · asked by Anonymous

2007-04-27 09:37:45 · 3 answers · asked by traych24 2

The rontgen or roentgen (R) is a unit of measurement of ionizing radiation in air, either X or gamma rays. It is named after the German physicist Wilhelm Rontgen. A roentgen is the amount of radiation required to liberate a pair of positive and negative charges from atoms of one electrostatic unit of charge in 1.00 cm3 of air at standard temperature and pressure. This corresponds to the generation of approximately 2.08 × 109 ion pairs. A dose of 500 R in five hours is lethal for humans.



If X radiation ionizes 7.5 × 1012 atoms per cemtimeter cubed, what is the ionizing intensity of the radiation measured in roentgens ?

2007-04-27 09:34:06 · 2 answers · asked by Anonymous

Capture of a neutron by molybdenum-98 produces what new element or isotope ?

2007-04-27 09:33:40 · 2 answers · asked by Anonymous

Choices: 1.) [Cr(OH2)6]3+ 2.) [V(OH2)6]2+ 3.) [Ti(OH2)6]3+ 4.) [Zn(OH2)6]2+ 5.) [Ni(OH2)6]2+

2007-04-27 09:13:14 · 1 answers · asked by haji_kwang 1

Choices: 1.)CN- 2.) en(enthylenediamine) 3.) NO2- 4.) CO 5.) I-

2007-04-27 09:09:19 · 1 answers · asked by haji_kwang 1