Chemistry - November 2007

Why does the reaction of Chromium and HCl turn the solution to green? And why does the reaction of Chromium and H2SO4 (sulfuric acid) turn the solution to bluish green? Does anyone know???

2007-11-16 07:47:40 · 3 answers · asked by curious 1

Which of the following statements are true for the reaction


HC2H3O2(aq) + KOH(aq) →




a) Water is a product

b) When balanced the coefficient of OH->(aq) is 1

c) The molecular equation is the net ionic equation

d) H+(aq) does not appear in the net ionic equation

e) H2O(l) appears in the net ionic equation



Examples of species are (aq) (s) (l) etc.


there can be more than one correct answer

2007-11-16 07:44:13 · 3 answers · asked by Anonymous

i will be thankfull if U wright the burning formoula of Mg,P &S too. :)

2007-11-16 07:38:31 · 2 answers · asked by ZiZi 1

Please can you help me with these equation things?
A- copper
B- iron
C- sodium
D- water

(a) copper oxide + sulfuric acid to copper sulfate + ( either A, B , C or D)
(b) copper sulfate + iron to (............) + iron sulfate
(c) iron oxide + carbon to ( .............) + carbon dioxide
(d) titanium chloride + (...................) to titanium + sodium chloride

THANKS, and if you could, please can you explin how these are done? I have forgotten s i haven't done them for a year and got very confused!:)

2007-11-16 07:23:26 · 2 answers · asked by Anonymous

In the reaction:
PCl3 + Cl2 = PCl5
the bond energy for Cl-Cl is 243 kj/mol and for P-Cl it is 331 kj/mol

I know that bond energy for a reaction = sum of energy bonds broken - sum of energy of bonds formed

so how exactly would i find the bond energy?

2007-11-16 07:16:40 · 4 answers · asked by starz8 2

I need to find the concentration of water in 1M HCl. I measured the density of 1MHCl as .9886g/mL
Can someone help me out here?
I'm drawing a blank.

2007-11-16 07:05:48 · 4 answers · asked by Anonymous

2007-11-16 06:29:54 · 4 answers · asked by orion 2

I carried out an experiment to investigate the thermodynamics of the ammonium carbamate dissociation.

NH2COONH4 (s) <--> 2NH3 (g) + CO2 (g)

Measurement of the dissociation pressure at a particular temperature enables the equilibrium constant and delta G standard at that temperature to be calculated. From measurements of the dissociation pressure over a range of temperature, the mean delta H standard and delta S standard may be calculated.

Why were the readings taken with descending temperature?

Equipment used was ballast chamber, vacuum line, pump, pressure gauge, cold trap, isoteniscope, stirrer etc...

Thank you in advance.

2007-11-16 06:23:18 · 1 answers · asked by Anonymous

2007-11-16 05:57:45 · 1 answers · asked by aznboi6623 1

An silver block of volume 0.16 m3 is suspended from a spring scale and immersed in a flask of water. Then the silver block is removed, and an aluminum block of the same volume replaces it.
(a) In which case is the buoyant force the greatest, for the silver block or the aluminum block?
the buoyant force is the same for each
aluminum block
silver block

(b) In which case does the spring scale read the largest value?
silver block
aluminum block
the scale reading is the same for each

(c) Use the known densities of these materials to calculate the quantities requested in parts (a) and (b). Are your calculations consistent with your previous answers to part (a) and (b)?
Material Buoyant force Scale reading
silver N N
aluminum N N

2007-11-16 04:53:18 · 1 answers · asked by Butterfly <3 2

Copper metal has a specific heat of 0.385 J/g·°C. Calculate the amount of heat required to raise the temperature of 22.8 g of Cu from 20.0°C to 875°C.

A. 1.97 × 10−5 J
B. 1.0 × 10−2 J
C. 329 J
D. 7.51 kJ
E. 10.5 kJ

2007-11-16 04:42:11 · 1 answers · asked by Anonymous

How much energy would be required to eject all the electrons from .10 mol of F ^(8+) in the n=2 state. Experess your answers in kJ

2007-11-16 03:54:38 · 1 answers · asked by Holly H 1

does some one know how to calculate the dipole moment........for instance say NH3.......

2007-11-16 03:10:27 · 3 answers · asked by shreyas 2

Why is it that borax still dissolves at room temperature, when it's deltaG is postive?

2007-11-16 02:25:35 · 1 answers · asked by Anonymous

for the following process, how do you calculate the change in internal energy of the system and determine whether the process is endothermic or exothermic

1. a 50g sample of water is cooled from 30 degrees celcius to 15 degrees celcius, thereby losing approsimatley 3140J of heat

2007-11-16 02:04:42 · 2 answers · asked by WynnLasVegas 1

I had the question when I was studying polymer physics. I can understand that polymers in melt will have smaller R than in good solvent (due to the space packing entropy as explained in de Gennes' book), but I could not understand why it should have exactly the some size as the non-self avoiding randomwalk.

2007-11-16 01:27:37 · 1 answers · asked by LI J 1

Since Deoxyribonucleic Acid is an acid, what is its Potential (Power) of Hydrogen (pH)? How can an acid carry genetic materials. Why is it an acid if there is no pH? Does DNA have a sour taste? If not, it could have been DNB (Deoxyribonucleic Base) or DNS (Deoxyribonucleic Salt). Who called it DNA and why is it named DNA? How can we taste DNA if it is a super-microscopic genetic material? Same goes to RNA.

2007-11-16 01:10:03 · 2 answers · asked by Kyle J 6

Is Polyhydroxyalkanoate (PHA) a biopolymer? Where can I find information on the production of PHA?

Also, what are the polymers of vinyl chloride and styrene? I know polyvinyl chloride and polystyrene are ones, but are there any others?

2007-11-16 01:00:18 · 4 answers · asked by Anonymous

??

2007-11-16 00:58:38 · 5 answers · asked by bagtack 2

2007-11-16 00:34:03 · 1 answers · asked by Sarah W 1

i have been searching the web for them over my lunch hour.i have found all the ones i need apart from these two.

2007-11-16 00:18:24 · 2 answers · asked by topher 2

Why would the pH i.e the hydrogen ion concentration of a solution affect its redox potential? Similarly why would the compound concentration (the concentration of the chemical species itself) affect the redox potential?

2007-11-15 23:47:00 · 3 answers · asked by Anonymous

2007-11-15 23:20:32 · 5 answers · asked by Anonymous

2007-11-15 22:40:05 · 13 answers · asked by ♥meRi.aN♥ 2

2007-11-15 21:58:58 · 3 answers · asked by MUKUL M 1

I'm talking about where c=n/V. Where c=concentration in moles/L, n=number of moles, V=volume in litres...

2007-11-15 20:57:53 · 6 answers · asked by youspinmerightround 2

It's violet, but I need to know why. Thanks.

2007-11-15 20:14:08 · 1 answers · asked by teknique 6

A child has become sick with lead poisoning from plates her parents bought. Since lead is so toxic what value does lead add to the production of plates? How is the lead and ceramic bound together?

2007-11-15 17:28:38 · 1 answers · asked by Eddie J 1

2007-11-15 16:58:38 · 1 answers · asked by Mavis O 1

The solubility product constant for Ag2SO3 is 1.5x10^-14
Calculate E for the process

Ag2SO3(s) + 2e- === 2Ag(s) +SO3-2

i cant find the half cell of the sulfur reaction

Thanks for the help

2007-11-15 16:05:44 · 1 answers · asked by nathaniel49 2