Chemistry - October 2007

2007-10-11 15:33:22 · 3 answers · asked by Anonymous

2007-10-11 15:28:58 · 2 answers · asked by Anonymous

2007-10-11 15:23:42 · 6 answers · asked by West 3

could someone please help me solve this? im almost there i just dont know the last step.
a person suffering from hyponatremia has a sodium ion concentration in the blood of 0.118 M and a total blood volume of 4.6L. what mass of nacl would need to be added to the blood to bring the sodium ion concentration up to 0.138M assuming no change in blood volume?
so heres what i did:
found the moles Na in the 0.118 solution: 0.543 moles
found the moles in the 0.138 solution- 0.635 moles
found the difference b/w the quantities: 0.092 moles
found that to be 2.12 g. but thats only Na. how do i get NaCl?
please help, i wont go to bed til i get this.

2007-10-11 15:08:57 · 1 answers · asked by Anonymous

given the specific heat of water which is 4.184 j/g*K How can you use this information to find the molar heat capacity?

2007-10-11 15:07:29 · 2 answers · asked by xiong L 1

Three 45g ice cubes at 0 degrees Celsius are dropped into 5.00x10^2 mL of tea to make ice tea. The tea was initially at 20.0 degrees Celsius; when thermal equilibrium was reached, the final temperature was 0 degrees Celsius. How much of the ice melted and how much remained floating in the beverage? Assume the specific heat capacity of tea is the same as that of pure water.

Please show work. Thanks a lot!

2007-10-11 15:04:09 · 1 answers · asked by Anonymous

ok so i have a lab where after you are done heating the magnism in the crucible and it is done reacting, it says you are suposed to use water to wash out the MgN and then boin the water away to help find the emprical formula of MgO. is adding the water and boiling it away nessary for the lab? or can it be left out and it wont make a difference?

i forgot to add the water in my orignal experiment and for my lab i have to prove that using the water isnt nessary. and toy can still come close to the right answer even though a step was left out.

2007-10-11 14:59:37 · 3 answers · asked by Sara S 2

2007-10-11 14:56:52 · 3 answers · asked by Yocool 2

The concentration of a certain sodium hydroxide solution was determined by using the solution to titrate a sample of potassium hydrogen phthalate (abbreviated as KHP). KHP is an acid with one acidic hydrogen and a molar mass of 204.22 g/mol. In the titration, 20.96 mL of the sodium hydroxide solution was required to react with 0.1082 g KHP. Calculate the molarity of the sodium hydroxide.

i got 0.0253M it was wrong

2007-10-11 14:44:17 · 1 answers · asked by My point exactly 5

I'm so lost. Please explain the steps that you did. And, of course, the answer. lol.
Thank you!

2007-10-11 14:40:38 · 4 answers · asked by Chelsey 5

Please explain the steps, I'm a bit lost on this concept...and of course, the answer.lol

Thank you so much!

2007-10-11 14:37:26 · 5 answers · asked by Chelsey 5

2007-10-11 14:35:34 · 3 answers · asked by Anonymous

2007-10-11 14:33:53 · 2 answers · asked by student217 1

2007-10-11 14:27:22 · 3 answers · asked by birdy 1

2007-10-11 14:27:14 · 2 answers · asked by sara w. 2

2007-10-11 14:26:09 · 4 answers · asked by sara w. 2

5.00 mL of concentrated HCL is diluted to give 25.0 mL of 1.60 M HCL. What was the molarity of the concentrated HCL?

The answer is 8.00 M.

The formula is Mi=Mv (i and v are subscripts) but I dont understand how to use it.

2007-10-11 14:23:15 · 7 answers · asked by Jamie 3

where is it found on earth??is it a living thing if yes which?? two interesting facts about element

2007-10-11 14:21:29 · 3 answers · asked by Anonymous

If I am determining the chemical formula of an ionic compound containing two moles of iron and three moles of sulfate ions per mole of the compound

I understand it would be set up as
2 moles Fe 2 Fe atoms
_______________ ___________
1 mole compound 1 formula unit

and

3 moles sulfate 3 sulfate ions
____________ ____________
1 mole compound 1 formula unit

What I don't understand is why the chemical formula is
Fe2(SO4)3 ... why isn't it Fe2S3?
Can someone please explain it to me... and why it is Fe2(SO4)3.

2007-10-11 14:13:57 · 4 answers · asked by decemberkitty02 3

please show a source

2007-10-11 14:08:09 · 1 answers · asked by Anonymous

okay does ANYONE know how to balance this equation?

*#* are subscripts... the numbers usually written on bottom
---> is yields or equals

Ca(OH)*2*+HNO*3* ----> Ca(NO*3*)*2*+H*2*O

2007-10-11 14:03:57 · 5 answers · asked by psh... 1

http://i2.photobucket.com/albums/y48/xxkrystinaxx9/che.jpg


Solve for A and B
then C and D

Please help! i cant figure this out

2007-10-11 13:57:35 · 1 answers · asked by Marcela M 1

my mom says she remembers a susbstance from her chemistry classes a long time ago.she forgets what it is called, but i will explain it. she said it was a semi solid substance that her chemistry teacher had in a jar a long time ago. the teacher would take prongs and take a little of the substance out of the jar and quickly put the lid back on. she said it was a grayish color and it would spontaniously combust when it touched air. what is this substance called?

2007-10-11 13:52:17 · 8 answers · asked by Anonymous

2007-10-11 13:44:45 · 5 answers · asked by dancer101_10 1

How do you find the valence number of electrons in elements on the periodic table?

Here are a few

Helium -
Chlorine-
Aluminum-
Boron-

2007-10-11 13:27:56 · 0 answers · asked by Anonymous

2007-10-11 11:29:21 · 5 answers · asked by romy_melendez 1

since hydrogen burns and oxygen burns and these two are important to start the fire?

2007-10-11 10:58:27 · 2 answers · asked by 1 1 2

Consider the reaction of CaCN2 and water to produce CaCO3 and NH3 according to the reaction

CaCN2 + 3H2O --> CaCO3 + 2NH3 :

How much CaCO3 is produced upon reaction of 45 g CaCN2 and 45 g of H2O?

1. 28 g
2. 19 g
3. 56 g
4. 250 g
5. 83 g
6. 38 g
7. 750 g

2007-10-11 10:57:58 · 3 answers · asked by Anonymous

2007-10-11 10:56:26 · 1 answers · asked by Anonymous

these are the only ones i couldn't do. help would be nice. please and thank you! (O and all the #'s are the subscripts)

H2O2 ==> H2O + O2

Na + H20 ==> NaOH + H2

C2H6 + O ==> CO2 + H2O

Mg(NO3)2 + K3PO4 ==> Mg3(PO4)2 + KNO3

2007-10-11 10:48:22 · 2 answers · asked by Andrea 2