Chemistry - December 2007

Express standard temperature in Kelvin and standard pressure in Kilopascals.

2007-12-10 13:54:10 · 1 answers · asked by (: Muffin Man :) 2

how long does it take to produce a real one? I always thought it was thousands of years. If so, aren't authentic diamonds limited? Wouldn't the value of diamonds increase?

2007-12-10 13:48:16 · 2 answers · asked by Anonymous

I need help making a science scavenger hunt for highschool age kids. I need some ideas. The topic is over Physical science

2007-12-10 13:44:31 · 1 answers · asked by newyork03 1

A chemist claims to have found a complex ion where the most intensely absorbed light is 342.0 nm. Estimate the crystal field splitting energy for this ion in kJ/mol

2007-12-10 13:22:49 · 3 answers · asked by jeniferrrr 1

2007-12-10 13:14:05 · 5 answers · asked by Kevin Lam 1

2007-12-10 13:02:54 · 11 answers · asked by laura v 1

What is the coordination number for each of the following.

(a) Na+ in the NaCl structure,


(b) Zn2+ in the ZnS unit cell,


(c) Ca2+ in the CaF2 unit cell

2007-12-10 12:51:22 · 2 answers · asked by Karma564 2

Ethanol, C2H5OH, melts at -114°C and boils at 78°C. The enthalpy of fusion of ethanol is 5.02 kJ/mol, and its enthalpy of vaporization is 38.56 kJ/mol. The specific heats of solid and liquid ethanol are 0.97 J/g·K and 2.3 J/g·K, respectively. How much heat is required to convert 78.0 g of ethanol at -127°C to the vapor phase at 78°C? The answer should be in kJ.

2007-12-10 12:49:55 · 1 answers · asked by Karma564 2

ok here it is, i'm doing a science project and it's on pH in water but i dont know what pH is, nor if lower the pH in the water the better or the lower the better, these are what i've tested; bottled water:9, aquarium water:10, tap water:12.
if i got them wrong or something please tell me but i just need to know what ph is better, lower or higher? thanks for helping me :]

2007-12-10 12:40:41 · 7 answers · asked by Anonymous

a blue solid is found to contain 36.84% nitrogen and 63.16% oxygen. what is the empirical formula of this compound?

is the answer NO2 or NO
because im not sure whether to round up or down

2007-12-10 12:36:01 · 1 answers · asked by corndog 1

I understand that forming the P=O drives the Wittig reaction forward but I am unable to comprehend why it helps initially when there is an overlap of the HOMO and LUMO? Does it lower the energy gap between the HOMO and LUMO?

2007-12-10 12:21:03 · 2 answers · asked by pwrfid 2

2007-12-10 12:19:46 · 2 answers · asked by Anonymous

1. Write a balanced equation for each of the reactions performed. Include the physical state of each substance. Classify each of the reactions as direct combination, decomposition, single replacement or double replacement.

Burning Mg:
2Mg(s) +02(g) > 2MgO (s) (? Type of Reaction)

Mg and HCl
Mg(s) + 2HCl(aq) >MgCl2(aq) + H2(g) (Single Replacement?)

Heating Cu
2Cu(s) +O2(g) > 2CuO(s) (? type of reaction)

H2O2 and MnO2
MnO2(s) + H2O2(aq)+2H(aq) > Mn2(aq) + O2(g) +2H2O (? Decomposition)

2KI + Pb(NO3)2 >PbI2 + 2KNO3 (? type of reaction)

2. Limewater is an aqueous solution of Ca(OH)2. Speculate on the identity of the cloudy white precipitate that forms with CO2 gas. Write a chemical equation for this reaction that is consistent with your observations.

3. A positive test for hydrogen was the "pop" test. What chemical reaction was occuribng? Write a balanced equations representing this reaction.

2007-12-10 12:19:27 · 2 answers · asked by Joey G 2

The volume of gas is 400.0 mL when the pressure is 1.00 atm. At the same temperature, what is the pressure at which the volume of the gas is 2.0 L?

2007-12-10 12:18:26 · 3 answers · asked by Hannah L 1

My little sister's doingg a science project...
she's onlyy 8 years old... help us please! =]

2007-12-10 11:56:27 · 10 answers · asked by Brenda 2

How do you balance: Sodium hydroxide reacts with phosphoric acid to produce trisodium phosphate and water?
Thanks

2007-12-10 11:56:15 · 4 answers · asked by mune_ga_arimasu_ka 2

2007-12-10 11:53:48 · 2 answers · asked by Anonymous

A solid sample of magnesium carbonate is heated strongly. how many total moles of products would be produced from 2 moles of reactant(s)?

2007-12-10 11:52:15 · 3 answers · asked by confusedkid 3

Water is added to a sample of solid magnesium nitride. Is the resulting solution acidic, basic, or neither?

2007-12-10 11:50:58 · 1 answers · asked by confusedkid 3

Since sulfur is associated with fire, I assumed that if it was injected into the body, one could burn up internally. But is that actually true?

2007-12-10 11:47:38 · 16 answers · asked by Anonymous

Whats is its molecular formula?

2007-12-10 11:41:02 · 2 answers · asked by Mzbee 1

Lead will react with hydrochloric acid to produce lead (II) chloride and hydrogen. How many moles of hydrochloric acid are needed to completely react with 0.36 moles of lead?

How would I go about solving this problem?

2007-12-10 11:37:57 · 4 answers · asked by Anonymous

ok, Na+H20 = NaOH + H2

2007-12-10 11:35:26 · 10 answers · asked by jessiisababe1212 1

1sodium oxide, NaO
2barium nitride, BaN
3cobaltous chloride, CoCl3
4stannic fluride,SnF4

2007-12-10 11:32:07 · 4 answers · asked by basketballrules420 1

As(OH3)+H2(SO4) ---> As2(SO4)3 + H20

2007-12-10 10:38:01 · 3 answers · asked by Anonymous

C12H22O11--->??
The numbers are the subscripts and the last letter is an "O" for oxygen by the way : )
I have the reaction but not the products, do any of you know how to find the product side of the equation? This is an extra credit assignment and if I get this, then my grade will boost up to an A. YAY!! Oh and could you guys also write what is the product name too for example: Sodium Chloride, please and thank you : )

2007-12-10 10:10:37 · 5 answers · asked by Anonymous

its the number of valence electrons right?

2007-12-10 10:10:21 · 4 answers · asked by Anonymous

I've been stuck on this for almost half an hour now, any help would be greatly appreciated, please give instructions on how to balance it. Thanks:

Pb(SO4)2 + LiNO3 -> Pb(NO3)4 + Li2SO4

2007-12-10 09:59:47 · 4 answers · asked by Anonymous

Radon-222 decays to a stable nucleus by a series of three alpha emission and two beta emission. what is the product?
A positron collides with an electron. what is the product of this collision?

can someone please help me out? thanks

2007-12-10 09:59:18 · 1 answers · asked by abc 1

how do i do this problem. it says PH= - log [H+] and [ H+]= 4.2x10^-8

do i just plug it in or wat?

2007-12-10 09:44:10 · 6 answers · asked by NoName 3