Chemistry - August 2007

A compound is composed of element x and hydrogen. Analysis shows the compound to be 80% x by mass, with three times as many hydrogen atoms as x atoms per molecule.
which element is element x
the answer is carbon but why????
please explain

2007-08-13 08:07:58 · 3 answers · asked by jazzchick 2

consider the formation of a solution of aqueous potassium chloride. Write the thermo chemical equations for
a. the conversion of solid KCl into its gaseous ions
b. the subsequent formation of the solution by hydration of the ions.
The lattice energy of KCl is -690 kJ mol^-1, and the hydration energy of the ions is -686kK mol^-1. Calculate the heat of solution of KCl in kJmol^-1

2007-08-13 07:27:31 · 1 answers · asked by kat 2

1.A solid non metallic element that is trivalent in its compounds
2.A solid non metal element that is tetravalent in its compounds
3.A solid metallic element that is monovalent n all its compounds
4.A gaseous element that is monovalent in all its compounds

2007-08-13 07:00:28 · 2 answers · asked by lamide e 1

electrons is a/an
A. insulator
B. conductor
C. capacitor
D. coulomb

2007-08-13 06:58:14 · 2 answers · asked by Anonymous

Why does sugar dissolve in water and flour does not?

2007-08-13 06:23:54 · 3 answers · asked by beatme 3

How many moles of NaOH are required to prepare 0.250L of 6.68M NaOH?

2007-08-13 06:14:15 · 4 answers · asked by philip c 1

Calculate molarity of a 125mL aqueous solution containing 23.5g sodium sulphate (Na2SO4)

2007-08-13 06:08:06 · 3 answers · asked by philip c 1

2007-08-13 04:54:16 · 5 answers · asked by diliprasad23 1

Q1: what radiation from the sun reaches the earth? (after passing through ionosphere, mesosphere, and stratosphere.. )

Q2: can u think of any useful photoreaction on earth (other than sun tanning) ? try to write a chemical equation..

thanks!

2007-08-13 03:06:00 · 3 answers · asked by k_mal116 1

2007-08-13 03:05:07 · 1 answers · asked by loally 2

im not sure about my answers
and if you can answer these too:
a 100 ml graduated cylinder
a 10 ml pipette
the weight of a substance with your balance
the dimensions of a solid using a ruler
thanks!

2007-08-13 02:32:14 · 4 answers · asked by spiderpig 2

in other words.. relavance of chemistry in the field of energy...
and i need examples and like the most recent activities.. or say examples..
and PLS tell ME THE SOURCES

2007-08-13 01:37:50 · 1 answers · asked by caramush 1

prefer to be cheap

2007-08-13 01:30:17 · 2 answers · asked by asal a 1

2007-08-13 00:25:31 · 2 answers · asked by cherry mae i 1

Is their a poison whose symptoms resemble heart disease? Need to know for a story I'm writing. I want to be accurate so I don't want to make it up...

2007-08-13 00:24:54 · 4 answers · asked by Anonymous

2007-08-13 00:21:50 · 4 answers · asked by asal a 1

I really don't get it...why do empirical formula have ratios and how do molecular formula involved in empirical formula...I read some sites..but I can't understamd it,,

anybody who's willing to explain it...you can show some problems..if you want..

well, thanks in advance...

2007-08-12 21:41:20 · 1 answers · asked by Anonymous

2007-08-12 19:10:17 · 4 answers · asked by akexyaya 1

Is there a way, without going to a jeweler, that I can determine whether a piece of jewelry I was given is gold plated or solid gold?

2007-08-12 17:05:14 · 2 answers · asked by Martin P 1

2007-08-12 16:15:38 · 3 answers · asked by Anonymous

Are there 2 liquids that you can mix together, to make fire? Example- I have a liquid in jar 1, and i pour an x amount of liquid in liquid one, and have fire develope.

2007-08-12 16:09:39 · 5 answers · asked by Anonymous

2007-08-12 14:55:22 · 2 answers · asked by herliati2004 1

2007-08-12 14:05:46 · 1 answers · asked by i-sena 1

2007-08-12 13:38:13 · 2 answers · asked by Evan P 1

i have to calculate the standard entropy change (DeltaS^o) for the following equation:

4NH3(g) + 7O2(g) ---> 4NO2(g) + 6H2O(g)

and from the table in the book the values for the standard entropies are:

NH3(g) = 192.3 J/mol*K
O2(g) = 205.0
NO2(g) = 240.0
H2O(g) = 188.7

the answer in the back of the book for the problem is -112 J/K

no matter what i try i can't get the right answer :( does anyone know how to solve this?? thanks!!

2007-08-12 12:02:58 · 4 answers · asked by Anonymous

Is there any substance that I can put to ordinary paper so it neutralizes it and it won't deteriorate in time?

2007-08-12 12:02:49 · 2 answers · asked by nikki 1

Is it already in it's simplest form?

2007-08-12 11:46:53 · 5 answers · asked by Pretty_Trini_Rican 5

2007-08-12 11:27:51 · 6 answers · asked by C'est Comme Un Rêve 3

I don't know how to type them on the computer but....

(delta)H(superscript with a degree symbol)(subscript with an f)?

(delta)H(superscript with a degree symbol)(no subscript)?

2007-08-12 11:08:13 · 10 answers · asked by Liz 4

a. 2-butanol
b. 2-pentanol
c. 2-methylpropanol
d. 2,2-dimethylbutane
e. pentanal

2007-08-12 10:30:11 · 4 answers · asked by sikhism4life88 1