Chemistry - December 2007

Which isotope, when bombarded with oxygen-18, yields the artificial isotope seaborgium-263 plus 4 neutrons?

A. nobelium-245
B. radium-259
C. californium-245
D. nobilium-249
E. californium-249

I worked out the problem myself, but am unsure if my answer is correct. Could you please show me the results in your steps? (TIA)

2007-12-09 17:28:01 · 1 answers · asked by xxxladyxxx 1

Please help me. I am not sure how to answer the question. Could you break it down so I can get a greater understanding of it. (TIA)

2007-12-09 17:02:08 · 2 answers · asked by xxxladyxxx 1

1.028 g- mass of barium sulfate

2007-12-09 16:40:19 · 4 answers · asked by Anonymous

A sample of moon rock was found to contain 78 argon-40 atoms for every 22 potassium-40 atoms. The age of the rock is...

a. 8.1 x 10^[-]10 yr
b. 2.4 x 10^9 yr
c. 2.8 x 10^9 yr
d. 4.6 x 10^9 yr
e. 6.8 x 10^9 yr

&& How do you answer/breakdown a sort of question like this? (((THANK YOU))).

2007-12-09 16:37:35 · 2 answers · asked by xxxladyxxx 1

which is larger in atomic radius? Nitrogen or Boron and why?
which is larger in ionic radius? Rb+ or Br- and why?
which is larger in electronegativity? Oxygen or Sulfur and why?

i dont get trends at all :[
help
thanks!

2007-12-09 16:32:33 · 1 answers · asked by shynhuggable 3

Is it because the vector created by the 2 bromines cancel the vector of the 2 lone pairs? If so, how can this be? Isn't the vector created by the lone pairs 'stronger' than the vector created by the 2 bromines?

2007-12-09 16:01:56 · 7 answers · asked by Anonymous

2007-12-09 16:01:28 · 1 answers · asked by Anonymous

given this formula

C6H12 (l) + 9 (O2) (g) ---> 6 (CO2) (g) + 6 (H2O) (l)
and that the heat of formation for C6H12 is -151.9 kj/mol

find the work done, how do you do this

2007-12-09 15:53:49 · 2 answers · asked by abrakadabra a 1

A 20.0mg sample of protien is dissolved in water to make 25.0ml of solution. The osmotic pressure of the solution is .56mmHg at 25C. What is the molar mass of proteien?

I really need help on this please guys

thanks

2007-12-09 15:24:05 · 2 answers · asked by Anonymous

I'm stuck on my hw which is due tomorow. It's chemistry and it's giving me differents substances like CO2 and oxygen and hydrogen. I just need the formula to convert litres into grams. Thank you for your help.

2007-12-09 15:21:09 · 4 answers · asked by Jennifer N 1

I'm doing a review and this one has me stuck. If someone could break it down for me and give me the answer, and tell me how they got it, you will get many points and much respect. Please and thank you.

-- The complete burning of Ethane, C2H6, produces CO2 and water vapor as its only products. Assume all substances are gases measured at the same temperature and pressure. How many liters of Ethane and Oxygen would produce 7.07 L of CO2?

2007-12-09 15:19:38 · 2 answers · asked by Anonymous

A buffer solution is 1.00 M in HF and 1.20 M in NaF. If 0.100 moles of HCl are added to 1.00 L of the buffer, what is its pH? Assume the volume remains constant. Ka of HF = 7.2 10-4.

2007-12-09 15:13:29 · 1 answers · asked by dillionfools 2

Or really in any heat

2007-12-09 15:04:45 · 1 answers · asked by Anonymous

how do you balance KClO3 by decomposition and Na2COs by dissociation?

are oxidation numbders needed to find the answer? && do you split up KClO3 in three parts or two?

2007-12-09 14:54:18 · 1 answers · asked by cheerios 3

2007-12-09 14:52:15 · 4 answers · asked by d-co 1

Are acids bonded ionically and bases covalently or is it vice versa?

2007-12-09 14:50:16 · 2 answers · asked by Anonymous

2007-12-09 14:43:10 · 2 answers · asked by brenda m 1

I HAVE A HUGE PROJECT DUE TOMORROW AND I HAVE NO IDEA WHAT MAKES BROMINE LEVELS HIGH

2007-12-09 14:42:05 · 3 answers · asked by Anonymous

A medical researcher hypothesizes that a newly developed medication can reduce high blood pressure.

A) The number of particiants in the study
B) The ages of people treated for high blood pressure with other medications.
C) The blood pressure of the participants in the study
D) The number of people treated for high blood pressure with other medications

2007-12-09 14:39:30 · 3 answers · asked by XOXO 1

Calculate the calorimeter constant in Calorie/Degrees Celsius.
(Calorimeter constant = 227.0 J/Degrees Celsius)

2007-12-09 14:39:21 · 2 answers · asked by Green Jeans 1

2007-12-09 14:31:46 · 0 answers · asked by skwstudent 1

i'm doing a project on chlorine ph and bromine levels

2007-12-09 14:26:01 · 1 answers · asked by Anonymous

2. A 2.50 L of neon has a pressure of 1.59 atm at 45.0 degrees celsius. What volume would the sample have if the pressure is 725 Torr and the temperature 22.0 degrees celsius?
A. 3.87 L
B. 0.733 L
C. 307 L
D. 2.04 L
E. 1.62 L

2007-12-09 14:21:41 · 3 answers · asked by Anonymous

2007-12-09 14:17:01 · 2 answers · asked by chocolate 1

2007-12-09 13:33:31 · 1 answers · asked by Lala T 1

If not, can you correct them please? Thanks!

S2– [Ne] 3S2 3P6

Fe3+ [Ar] 4S2 3D3

2007-12-09 13:29:04 · 3 answers · asked by Anonymous

I have to classify the following as synthesis, decomposition, or replacement. I'm confused and don't understand!

1.burning wood
2.burning gasoline
3.burning candle
4.burnt waffles
5.milk gone sour
6.wood rot
7.frying eggs
8.baby spit up
9.green penny
10.baking cookis
11.lighting a match
12.cooking a turkey
13.rusted nail
14.throw up
15.brown apple
16.glow stick
17.turning on the light
18.grilled steak
19.leaves changing color
20.spray 'n wash
21.baking a cake
22.making pancakes
23.taking a picture


I'm not asking for you to tell tell me what each one is, I'm just wondering if you could tell me in general what burning, baking, etc. are classified as. Thank you so much in advance!!

2007-12-09 13:27:52 · 1 answers · asked by Anonymous

It is true that the complete combustion of a hydrocarbon can do more work than incomplete combustion. Compare the work ΔG done by the combustion of one mole of ethane undeer these conditions.
Incomplete combustion: 2 C2H6 (g) + 5 O2 (g) → 4 CO(g) + 6 H2O (g)
Complete combustion: 2 C2H6 (g) + 7 O2 (g) → 4 CO(g) + 6 H2O (g)

can someone please help me solve this problem? and show how it is done.
thank you

2007-12-09 13:14:17 · 1 answers · asked by abc 1

The colour change was that it began to get clearer. I need to determine the direction of the equilbrium shift and the reason for this shift.
I know that Fe^3+ is colourless, SCN^- is colourless, and Fe(SCN)^2+ is blood red.

2007-12-09 13:11:03 · 2 answers · asked by Anonymous

Jessica shines a lamp that emits a variable intensity light on a photoelectric cell. She notices that a current can be detected on the current indicator. When the lamp is turned on, no current is detected. Even increasing the intensity of the light t the maximum level has no effect.

Jessica repeats the experiment with a different lamp. When the lamp is turned on, no current is detected. Even increasing the intensity of the light t the maximum level has no effect.

2007-12-09 13:07:25 · 2 answers · asked by Haylee S 1