Chemistry - October 2007

please help.

2007-10-04 09:01:49 · 4 answers · asked by Anonymous

2007-10-04 08:53:53 · 4 answers · asked by kendra 1

What are the chemical and physical properties of the fourth period metals ? up to Mn. So k , Ca, Sc, Ti, V, Cr, and Mn? how do i predict these properties?

2007-10-04 08:40:26 · 2 answers · asked by Anonymous

Hi,

I know that copper can be turned to gold through nuclear reactions, but it only fomrs a radioactive/unstable isotope this way. This question is referring to alchemy being possible or not.

2007-10-04 08:21:06 · 6 answers · asked by J Money 1

Here we go. We tested an unknown substance for reducing sugars, using the standard Benedict's reagent. The only thing we suspected was in the solution was aspartame. Strangely enough, the substance produced a dark blue colour at the end of the test, significantly darker than the original turqouise benedict's colour. Suspecting contamination, we ran it twice more, and found the same results. Any ideas?

2007-10-04 08:17:50 · 1 answers · asked by Anonymous

2007-10-04 06:49:36 · 1 answers · asked by hayzman22 1

water has one of the largest specific heats of any substance. why is it important to the human body?????

2007-10-04 06:18:31 · 4 answers · asked by dhana 1

I know how to find the mass, i just need to know what steps do i need to do in order to do this. Like what kind of equipment would i need: graduated cylinder, beaker, stuff like that and I need to know how much water do i need in order to do this!!!!! Anyone please! Thanks

2007-10-04 06:11:51 · 3 answers · asked by B9O9R9I9C9U9A 3

The following reaction is at equilibrium at one atmosphere, in a closed container.
NaOH(s) + CO2(g) ↔ NaHCO3(s)
Which, if any, of the following actions will decrease the total amount of CO2 gas present at equilibrium?
adding N2 gas to double the pressure
adding more solid NaOH
decreasing the volume of the container
removing half of the solid NaHCO3
none of the above

2007-10-04 06:06:00 · 2 answers · asked by jennifer 2

It's probably obvious but I can't find the exact answer anywhere. All help appreciated.

2007-10-04 05:38:09 · 2 answers · asked by Ethereal 4

Why do you need to use "excess" Benedict's reagent if you want to get an idea of the concentration of a sugar solution?
And how could you use the Benedict's test to estimate the concentration of a solution of a reducing sugar?

2007-10-04 05:33:53 · 3 answers · asked by Anonymous

a 563-mg sample containing only CaCO3 (100.1 mg/mmol) and SrCO3 (147.6 mg/mmol) is dissolved in an acid; Na2C2O4 is added to precipitate CaC2O4 (128.1 mg/mmol) and SrC2O4 (175.6 mg/mmol). The oxalate precipitate is filtered and dried to yield 703 mg of the anhydrous mixed oxalates. Calculate the percentages of CaCO3 and SrCO3 in the mixture. Show ALL your work!!

2007-10-04 05:25:21 · 3 answers · asked by macjack 1

1. What is the name given to acids?

2. What is the most common indicator that is used to determine if a substance is an acid or base?

3. What are compounds that taste bitter and feel slippery? Soaps, detergents, and shampoo are common examples.

4. What is the name given to bases?

5. What are compounds that taste sour and react with metal? Common examples are hydrochloric and sulfuric.

2007-10-04 05:18:10 · 2 answers · asked by V.S. 2

2007-10-04 05:15:42 · 2 answers · asked by booyeakasha 2

Is it:
con.H2SO4 / heat; H2 / Pt
(or)
KOEt/EtOH/heat; H2/Pt

2007-10-04 04:58:41 · 2 answers · asked by student217 1

Assuming that the volume and temperature of the reaction mixture remain constant, what is the percent change in pressure if the reaction goes to completion?

A(g)+ 2B(g) ----->2 C(g)

A reaction mixture initially contains 1.4 L of A and 1.8 L of B.

2007-10-04 04:44:13 · 1 answers · asked by Anonymous

i need to find out as much as possible in two days . [please help me as best you can !!!!!!!!!]
thanks

2007-10-04 04:40:01 · 2 answers · asked by victoria 1

sodium
potassium
calcium
iron

2007-10-04 04:33:07 · 2 answers · asked by tia 3

A 3.00-L flask is filled with gaseous ammonia, NH_3. The gas pressure measured at 23.0 degrees C is 1.55 atm.

2007-10-04 04:31:23 · 1 answers · asked by Anonymous

If so at what temperature does this occur?

2007-10-04 04:25:32 · 5 answers · asked by Nick R 2

gain electrons
lose electrons
gain protons
lose protons

2007-10-04 04:21:48 · 5 answers · asked by tia 3

1)
NH4OH + HC2H3O2----------->H2O + NH4C2H3O2
W.Elec. W.Elect ionic/soluble
2)
HCL + Mg(C2H3O2)2 ------------->MgCl2 + HC2H3O2
St.Elec. Ionic/soluble ionic/soluble W.Elec.
3)
NaHCO3 + H2SO4 --------->NaSO4 + H2CO3
ionic/soluble St. Elec. Ionic/soluble W.Elec.

2007-10-04 04:19:13 · 2 answers · asked by Christina S 1

2007-10-04 03:35:42 · 3 answers · asked by Anonymous

I missed 1 day from being sick so all of this stuff is really throwing me for a loop. I need to understand all of this stuff for an exam tomorrow. Please help if you can and show steps that got you there. Thank you so much in advance!

The Hindenberg was a famous hydrogen-filled dirigible that exploded in 1937. What mass of hydrogen was needed to fill the craft at 23 degrees Celsius and 1.0 atm if the volume was 2.23 x 10^5m^3?

What mass of zinc was needed if the Germans used the reaction of zinc and 10.0-M hydrochloric acid to produce the gas the fill the Hindenberg in the previous problem?

2007-10-04 02:42:48 · 4 answers · asked by LIO 2

This video from New Scientist seems to imply that it is:
http://www.youtube.com/watch?v=pIvAl4lu1uA&feature=dir

What is the definition of a plastic, and does paneer fit into this definition? If not, did they make plastic on the New Scientist video?

2007-10-04 01:34:31 · 5 answers · asked by Robin M 1

Why we must blend our sample with that mixture (HPO3-HOAc)?

2007-10-04 01:09:04 · 1 answers · asked by thereddevil_mania 1

A pharmaceutical chemist runs a chromatography test on a substance and identifies two of its components by comparing their Rf values against certain standards. If the two components have Rf values of 1.0 and 0.41 and the solvent front has traveled 12.0 cm from the samples origin, what is the separation distance on the chromatogram??

2007-10-03 19:23:06 · 2 answers · asked by Anonymous

2007-10-03 19:22:20 · 3 answers · asked by Anonymous

Also, where can I look to find the expected Rf value for this solute in the solvent you suggested. Thank you in advance.

2007-10-03 19:18:50 · 1 answers · asked by lhvinny 7

A pharmaceutical chemist runs a chromatography test on a substance and identifies two of its components by comparing their Rf values against certain standards. If the two components have Rf values of 1.0 and 0.41 and the solvent front has traveled 12.0 cm from the samples origin, what is the separation distance on the chromatogram??

2007-10-03 19:09:01 · 1 answers · asked by Anonymous