Chemistry - November 2007

Express your answer in scientific notation.

I know it's something like pH= -log [H+], but I cannot figure it out for the life of me.

2007-11-22 10:53:08 · 1 answers · asked by ms_lotr_freak 3

EX:
NEON-
I'm quite a gas that will brighten a light, so use me in your signs for a colorful delight!

2007-11-22 10:18:51 · 5 answers · asked by Anonymous

2007-11-22 09:45:45 · 7 answers · asked by Anonymous

I have been given a graph of the amount of solubility of two substances. I don't know if it is possible without the graph, but I need help with these questions...

Substance A
Temp./Solubility (g/100gH2O)
0/20
20/34
40/46
60 /58
80 / 72
100 /86

Substance B
0 /10
20 /18
40 /37
60 / 61
80 /100

1) What mass of substance A would you need to add to 325g of water to saturate the solution at 25 C?

2) 27g of substance A is added to 60g of water. At what temperature will the solution be saturated?

3) A saturated solution in 68g of water is cooled from 70 C to 55 C. Waht mass of the solute will crystalize out?

5) You have a saturated solution in 140g of water of substance A at 20 C. What mass of water must you have to contain a saturated solution of substance B at that temperature, given the same amount of solute?

Thanks :)

2007-11-22 09:45:29 · 2 answers · asked by Marie 2

2007-11-22 09:40:51 · 4 answers · asked by Anonymous

2007-11-22 09:28:22 · 4 answers · asked by amber s 2

I have been given a graph of the amount of solubility of two substances. I am not sure how to complete these questions. Could someone just tell me what I am supposed to do, or show me a formula that I can use to solve them? I know it is hard without the graph. Thanks :)

1) What mass of substance A would you need to add to 325g of water to saturate the solution at 25 C?

2) 27g of substance A is added to 60g of water. At what temperature will the solution be saturated?

3) A saturated solution in 68g of water is cooled from 70 C to 55 C. Waht mass of the solute will crystalize out?

4) If you had a saturated solution in 30g of water each of substance A and substance B, what would be the difference of solute at 45 C?

5) You have a saturated solution in 140g of water of substance A at 20 C. What mass of water must you have to contain a saturated solution of substance B at that temperature, given the same amount of solute?

I really just need formulas, if possible. Thanks! :)

2007-11-22 09:15:46 · 2 answers · asked by Marie 2

For instance if we have CaO+H2O->Ca(OH)2
and want to find out how much caclium hydroxide will be
produced when 10g of calcium oxide reacts with 3g of water?
What is the reason/s why we cannot do a direct gram comparison instead of converting to moles to find the limiting reactant? Please help thanks!

2007-11-22 09:03:55 · 3 answers · asked by Gideon 1

My question is ; What mass of calcium chloride is produced from 2 grams of calcium carbonate?

I know that I have to write down the 2 formulas which would be Calcium Chloride > CaCl2 and Calcium Carbonate CaCO3, and then add up there relative atomic masses and add them up, they then should be equal, but when I add them up Calcium Chloride ends up as 112g and Calcium Carbonate 100g. They need to be equal can anyone tell me where im going wrong? Thanks :)

2007-11-22 08:22:57 · 2 answers · asked by Anonymous

The question is...
A proton, neutron and electron, all with the same velocity, pass between the poles of a permanent magnet. Which is deflected most? And why? I really have no idea except i dont think its neutron. :(

2007-11-22 08:17:51 · 2 answers · asked by Anonymous

On the back of an antibacterial soap that I bought, it says that it contains 0.6% Triclosan. What is meant by that. Is it 0.6 % of the bottle is troclosan or is it something like weight/volume (0.6g/Liters)

thanks a bajillion!!

2007-11-22 08:15:11 · 1 answers · asked by Crazyfred02 1

The question from the text:

Are the following substances electrolytes or non-electrolytes? Write equations to illustrate your answers.

I'm unsure about a couple of them. I'd like to just be sure I'm going about this correctly:

substance: C2H5OH(l) in water
My equation: C2H5OH(l) --[in water]--> C2H5OH(aq); non-electrolyte.

substance: O2(g)
My equation: O2(g)--[inwater]-->O2(g); non-electrolyte

2007-11-22 08:01:58 · 3 answers · asked by glurpy 7

If you are the parent of a lactose intolerant baby, describe why, in chemical terms, why you would have to carefully identify the substances in a can of baby formula before you feed it to your baby?

2007-11-22 07:14:12 · 2 answers · asked by Jada 1

I know two negatively charged ions (non-metals) can react and form a compound, but can two positively charged ions (metals/metalloids) do the same?

2007-11-22 07:05:46 · 2 answers · asked by black_star_47001 3

2007-11-22 07:03:12 · 1 answers · asked by Anonymous

A student prepares a solution by dissolving 3.72 g of NaOH in enough water to make 300. mL of solution.
The student then transfers 32.0 mL of this solution into a 100. mL volumetric flask. Water is then added
up to the 100. mL mark.
What is the final molarity of NaOH in the 100. mL flask ?

2007-11-22 06:37:01 · 3 answers · asked by jetschic28 1

we did an experiment on metal reactivities . the reactions was between three metals copper. magnesium and zinc and with three solutions copper, magnesum and zinc

what caused the formation of the color in the test tube during the reaction? please explain

2007-11-22 06:27:41 · 2 answers · asked by Anonymous

if we mix water with oil and juice, and we separate water from the other the other liquids by using its boiling point, we can state that we use water's PHYSICAL PROPERTY or PHYSICAL CHANGE???

2007-11-22 06:20:48 · 3 answers · asked by Anonymous

Hg(MnO4)2 = mercury permanganate
CO=carbon monoxide
CaHPO4=calcium hydrogen phosphate
AL(OH)3=aluminum hydroxide
K2SO4=potassuim sulfate
N2 O5=dinitrogen pentaoxide
Ni O=nitrogen monooxdie

2007-11-22 06:08:34 · 8 answers · asked by mohjd s 1

Theres this thing on the lewis structure and i dont understand it one bit i need help for single double and triple bonds: can som1 plz like do one example underneath and explain why and how?



PCL(subscript)3

C(subscript)2

CN

N(subscript)2S(subscript)3

HSF

SeO(subscript)2

2007-11-22 06:06:37 · 2 answers · asked by yankeesrule91692 1

The are certain mineral water products that bear the name O2 and are claimed to contain more oxygen (up to 15%) than normal water. Is this possible...? I water is H2O than how is this possible...wouldn't that just be hydrogen peroxide?..(it is a while since i had my chemistry classes..)

2007-11-22 04:54:57 · 8 answers · asked by Anonymous

Hi, could someone please walk me through this, I am a little confused.
The first thing I would do is find how many moles of Silicon (Si)
so 45.0 Si * 1 mol Si/28.1 g Si = 1.60 mole Silicon.

I am stuck on what to do next!

2007-11-22 04:54:29 · 1 answers · asked by Jada 1

In the van der Waals equation, why is a term added to the observed pressure and why is a term subtracted from the container volume to correct for nonideal gas behavior ?


DETAILS PLEASE !
thaaanks !

2007-11-22 04:41:36 · 3 answers · asked by Anonymous

example: Hydrochloric Acid = HCl

2007-11-22 04:35:11 · 2 answers · asked by WAKA 1

2007-11-22 04:33:32 · 3 answers · asked by Anonymous

i'm not sure if the correct answer would be 2H2 + O2 ---> 2H20

or 2H + .5O2 ----> H2O

2007-11-22 04:30:35 · 3 answers · asked by Jada 1

v= [1/4 - 1/n^2] * 329x10^15 s^-1.

i want the explanation of the whole formula.

thankz for your time

2007-11-22 04:23:18 · 1 answers · asked by Essien 3

Consider the following balanced equation in which gas X forms gas X2.

2X(g) --> X2 (g)

Equal moles of X are placed in two seperate containers. One container is rigid so the colume cannot change; the other container is flexible so the volume changes to keep the internal pressure equal to the external pressure. The above reaction is run each container. What happens to the pressure and density of the gas inside each container as reactants are converted to products?



Detailed Please ! =]
Thanksss !

2007-11-22 03:54:18 · 1 answers · asked by Anonymous

Tanya carried out an experiment in which she placed some iron wool into some blue copper sulphate solution.
In her book she wrote:
"I predict that the iron will react with the copper sulphate because iron is higher than copper in the reactivity series. I think that i will see some colour changes"

1) Describe the two colour changes Tanya would see that would show her prediction is correct.

2) Complete this word equation for the reaction:
iron + copper sulphate =

3) Tanya then repeated the experiment with zinc in place of iron. Compare the result you would expect to the result for iron.

All answers and explanations are much appreciated. Thanks

2007-11-22 03:14:42 · 1 answers · asked by Anonymous

In an sp hibrydized orbial we have 2 hybridized and 2 unhybridized orbitals. What is the order of filling? Do we start filling the hybridized orbitals first or the unhybridized?
E.g. if an atom has 5 valence elctrons, we put 1 on each orbital. but where does the 5th one go?

2007-11-22 02:58:18 · 3 answers · asked by Anonymous