Science & Mathematics - 26 September 2007

21) iodine-131 and iodine-127 are examples of __?
A nuclei
B isomers
C isotopes
D neutrons

22) the __ is where the electron is most likely to be found.
A energy level
B electron orbit
C electron coud
D orbit

23) in a lewis dot diagram, the dots represent __ in the atom.
A all the electrons
B the valence electrons
C the protons
D the neutrons

24) which groups are considered to be transition elements?
A 1 and 2
B 3 through 12
C 1,2 and 18
D 13 through 18

25) an example of a chemical formula is __.
A. Na
B. 4.5 g/mL
C. H2SO4
D. d= 13.6 g/l

2007-09-26 04:42:37 · 3 answers · asked by Anonymous in Chemistry

2007-09-26 04:41:09 · 3 answers · asked by forlaniz3 2 in Chemistry

2007-09-26 04:39:33 · 9 answers · asked by forlaniz3 2 in Chemistry

In LongDrug, there are 2 rubbing alcohol, ethyl alcohol and isopropyl alcohol. What is the difference between them? Thank you!

2007-09-26 04:39:27 · 3 answers · asked by JenJen 2 in Chemistry

The Sun is 1.5 x 10 to the 8th km away from Earth and has a diameter of 1.4 x 10 to the 6 th km. How large is the angle in the sky? Calculations?

2007-09-26 04:37:08 · 3 answers · asked by astronomy dummy 1 in Astronomy & Space

Question 4
The prob. of stock A rising is 0.3; and of
stock B rising is 0.4. What is the prob.
that neither of the stocks rise, assuming
that these two stocks are independent?
1. 0.42
2. 0.12
3. 0.88
4. 0.44
Question 5
If the above stocks are not independent,
and the prob. of both stocks rising is 0.09,
what is the prob. that neither stock rises?
1. 0.69
2. 0.39
3. 0.42
4. 0.52

2007-09-26 04:35:44 · 4 answers · asked by elgriff_2000 2 in Mathematics

2007-09-26 04:35:14 · 1 answers · asked by lana l 1 in Chemistry

Soon choosing my A-level subjects!

Really stuck I really want to do something in forensics!

Arrrr


HELP!

(In UK)

2007-09-26 04:34:43 · 2 answers · asked by Lynzy 5 in Chemistry

2007-09-26 04:34:40 · 2 answers · asked by forlaniz3 2 in Chemistry

For different cities in different countries. In degrees celsius. Need max and min for each day of September!

2007-09-26 04:32:25 · 3 answers · asked by Blair Waldorf 5 in Weather

6. the best way to understand the submicroscopic world is with ___
A. powerful microscopes
B. very accurate measuring devices
C. physical properties
D. models

7 an example of a chemical change is __
A. melting
b. electrical conductivity
c. burning
d. density

8 the structure of matter refers to its __
a. behavior
b. composition
c. measurements
d. reactions

9 water and hydrogen peroxide are both composed of atoms of hydrogen and oxygen, the differences lie in the __ arrangement of the atoms.
A. behavioral
B. composed
C. macroscopic
D. submicroscopic

10 when ice melts and becomes liquid water, it has undergone a __
A. chemical change
B. chemical propert
c. physical change
d. physical property

11 in ocean water, salt is a(n) __
a. alloy
b. solute
c. solution
d. solvent

12 how many atoms are present in one unit of sodium sulfate, Na2SO4?
A. 1
B. 2
C. 4
D. 7

15 the second row of the periodic table includes__ elements
a. 2
b. 8
c. 18
d. 32

2007-09-26 04:30:40 · 2 answers · asked by Anonymous in Chemistry

2007-09-26 04:30:29 · 2 answers · asked by wadood s 1 in Physics

in a container. What is the amount and concentration of sodium hydroxide solution she must add to this in order to end up with 8 liters of 27% solution? your help is greatly appreciated!!!

2007-09-26 04:26:47 · 2 answers · asked by sugar lady 1 in Chemistry

A hole is drilled through the center of Earth and very long L=100km sealed cylindrical pipe is inserted vertically into the hole. The pipe contains thermally insulated nitrogen gas, which is in equilibrium, has temperature T=400K, and pressure 1atm at the bottom.

Under these conditions the gas can be considered ideal, and pressure of the gas at the top of the pipe is negligible.
Its specific heat Cv = 5/2 R.

The pipe is initially at the sea level, and then is very slowly (adiabatically) lowered downward the center of the earth. As gravity decreases, the gas is able to expand and reach higher levels inside the pipe.

What is temperature of the gas when the pipe is half-way down to the center of the earth?
[in assumption of uniformly dense planet gravity at this point is g/2]

2007-09-26 04:25:30 · 3 answers · asked by Alexander 6 in Physics

I know it has something to do with the amount of water they displace and bouyance but can anyone give me a better idea as to why it is they float?

2007-09-26 04:25:02 · 4 answers · asked by rubenff2000 1 in Physics

2007-09-26 04:19:39 · 4 answers · asked by yam 1 in Botany

Begin graphing f(x)=x^3 (I did) then use transformations of this graph to graph g(x)=-1/2x^3

2007-09-26 04:14:45 · 3 answers · asked by ChillChick 4 in Mathematics

H2SO4+KOH= g + f

Now what i need here is the atomweight .. or something like that (sry ime from europe) if i know that the weight of the H2SO4 is 0.5 mol.

So basicly i need the atomweight of each and every element

2007-09-26 04:13:22 · 4 answers · asked by Simon T 2 in Chemistry

what 2 prime numbers multiplied together will give you a 400 digit number for the answer?

2007-09-26 04:11:18 · 6 answers · asked by Anonymous in Mathematics

2007-09-26 04:11:12 · 2 answers · asked by Richie57 1 in Engineering

Any kind of food additive will work,

2007-09-26 04:10:02 · 5 answers · asked by mark s 1 in Chemistry

2007-09-26 04:08:56 · 4 answers · asked by Richie57 1 in Physics

2007-09-26 04:03:23 · 10 answers · asked by michaeljamescarr 1 in Physics

the problem is: Calculate the density if the mass of a solid material is measured as 15.00 grams and its volume is measured as 5.0 cm^3? Round off your answer to the proper number of significant figures.

2007-09-26 04:02:33 · 3 answers · asked by IDchecker27 2 in Chemistry

a) which is the limiting reactant?
b) how many grams of NO and H2O form?
c) how many grams of the excess reactant remain after the limiting reactant is consumed?

2007-09-26 04:01:51 · 2 answers · asked by cherubimangel85 1 in Chemistry

could you please help me solve this?

An electric flat iron with a resistance of 60 ohms, an electric lamp with 50 ohms and a aradio with 1000 ohms are connected in parallel to a 220volt source. if all of the appliances are switched on, solve for

a. current through the flat iron
b. CURRENT THROUGH lamp
c. current through radio
d.total resistance
e. voltage across each resistor


please..i want to follow and know how to answer it so can you show me the solutions....please....

2007-09-26 04:01:34 · 3 answers · asked by Ninik 3 in Physics

I am confused as to what the difference is between large dinosaur-like prehistoric creatures (Such as the Dimetrodon) and actual dinosaurs (Like a Tyrannosaurus). On Discovery Channel specials, I'll see a show with two large creatures, and they'll say that one is a dinosaur, but another is not. Is there some sort of scientific distinction? I assume there is, but what is it?

2007-09-26 03:57:53 · 5 answers · asked by Grimjeff 2 in Zoology

Does any one know what this bug is called? It is about 3 inches long, Found in Central Florida, It appears to have its mate riding on its back (I assume the female is the larger one and the male is the smaller one) and they are black and have yellow lines going down there back. I was told they are called Devils Horses , but I cannot find them online any where... I found Devils Coach Horse but it is a completely different bug... Any one know? Here are 2 different links to two different pictures.

http://i239.photobucket.com/albums/ff20/joelovesleanne/100_3436.jpg
http://i239.photobucket.com/albums/ff20/joelovesleanne/100_3434.jpg

2007-09-26 03:57:52 · 4 answers · asked by Carolyn 2 in Zoology

2007-09-26 03:56:53 · 2 answers · asked by tangelo316 1 in Chemistry

Can you do the ideal gas equation but with an individual gas constant instead of the universal gas constant. The gas is air.

n-14
t-2773k
R-?
v-3 litres
p-?

2007-09-26 03:54:46 · 4 answers · asked by Anonymous in Physics