Chemistry - January 2007

I want to do cryogenics for my science fair project, and I found this on the internet.

2007-01-16 11:48:54 · 5 answers · asked by princess49872001 1

Any specific factors that change the pH of saliva?
Such as foods recently consumed and the like...?

2007-01-16 11:46:44 · 3 answers · asked by raxer 2

2007-01-16 11:39:44 · 8 answers · asked by Anonymous

"Ammonia is produced to sell as a fertilizer. Nitrogen from the atmosphere reacts with hydrogen gas to form gaseous ammonia at STP conditions. You must produce 1500 L of NH3 per month and the reaction process is 88% efficient. How many L of hydrogen gas must be purchased to meet the 1500 L quota?"

I can't seem to get the right answer...

2007-01-16 11:36:36 · 1 answers · asked by saira n 1

Fill the drinking glass with water up to the brim.

Place the cardboard on top of the glass and hold it down. Some extra water may escape.

Hold the cardboard against the glass with your fingers and turn the glass over.

Carefully remove your fingers.

You should be surprised and amazed by this strange occurrence.

Repeat the experiment with a new piece of cardboard and only one inch of water in the glass.

Could someone explain to me why the water stays in the glass? I don't have to know the answer to this question just yet but I read two different explanations that are probably saying the same thing...but they sound different to me

Ex. #1: The water stays in the glass because the pressure of the air outside the glass is greater than the pressure of the water against the cardboard.

Ex. #2: When you turned the glass upside-down, a small amount of water dribbled out without any air bubbling back in. Gravity was pulling down on the water and the water was pulling down on the air inside the glass. But being a gas, the air inside the glass spread out more. That meant the air molecules inside the glass weren't pressing against each other as hard as they were before. The air outside the glass, on the other hand, was pressing in on the cardboard just as hard as it ever was. And that difference in air pressure was enough to actually suspend the water in mid-air, with nothing more than air pressure keeping it from escaping.

2007-01-16 11:31:48 · 1 answers · asked by princess 1

2007-01-16 11:30:40 · 4 answers · asked by Anonymous

2007-01-16 11:15:50 · 4 answers · asked by Meno 1

2007-01-16 11:11:50 · 6 answers · asked by Anonymous

ICl
BiCl3
AsCl3
CCl4
OSCl2

2007-01-16 11:09:36 · 4 answers · asked by abbs 2

help me defind them?

2007-01-16 11:04:14 · 1 answers · asked by Anonymous

2007-01-16 10:54:01 · 5 answers · asked by Anonymous

I know that a needle needs to be inserted, etc., I need the chemistry aspect of it. What exactly is done to determine how much glucose there is and such? As much detail as possible please!!!

2007-01-16 10:52:42 · 3 answers · asked by Amanda M 2

Find the independent and dependent variable.

Shaggy told Velma that there were new Scooby Snax that will cause Scooby to focus more on a case than on cheese sandwiches. Shaggy gave Scooby the new snax. Then the results noted that Scooby focused 10% more than he usually focuses on a case.

2007-01-16 10:38:37 · 2 answers · asked by biancaonwenu 2

I was unclear; How would you be able to put a piece of metal into a very high temperature pre-heated oven for a short period of time and have the metals' temperature change minimal amounts.

2007-01-16 10:38:03 · 3 answers · asked by ☆ 2

Calculate the energy released when 10.0g of steam at 100oC, 1 atm is condensed and cools to 25oC. PLEASE show workings on how to do this problem.

2007-01-16 10:14:28 · 1 answers · asked by Special K 1

for HC2H3O2, is there only one mole of H+ or 4 to calculate the equivalent mass? I'm thinking one, but want to double check.

2007-01-16 10:04:59 · 4 answers · asked by Anonymous

2007-01-16 10:00:36 · 7 answers · asked by Lala 2

Is it true or false?

2007-01-16 10:00:28 · 5 answers · asked by 311Fanx0 2

Anything is acceptable

2007-01-16 09:56:39 · 3 answers · asked by RickySingh2006 2

To be stable, atoms with more than 20 protons need increasingly more:
a) neutrons than protons
b) electrons than protons
c) electrons than neutrons
d) protons than neutrons

2007-01-16 09:55:35 · 3 answers · asked by RickySingh2006 2

I'm teaching a very basic chemistry class at a local college, and I'm looking for ideas to intergrate the theory and math with something that occurs in my students daily lives. This is the first time I've taught this course, and I was only given a week heads-up, so any help would be very appreciated. Does anyone have any topics they might like to see covered, or ones that would be related to chemistry?

2007-01-16 09:52:51 · 4 answers · asked by Min02 4

I'm teaching a very basic chemistry class at a local college and need some very easy to set up and perform experiments. I do not have access to a lab, so the simpler the better. If it can be done with household objects, that would be fantastic.

2007-01-16 09:50:21 · 3 answers · asked by Min02 4

I need the equations of dissolution of calcium chloride and sodium bicarbonate in water please.

2007-01-16 09:49:48 · 3 answers · asked by Vlad M 1

I had to do an experiment about how thermometers work i am trying to do a lab report help me out

2007-01-16 09:48:50 · 3 answers · asked by angela b 2

if a piece of hard white blackboard chalk is heated strongly in a flame, the mass of the piece of chalk will decrease, and eventually the chalk will crumble into a fine white dust. does this change suggest that the chalk is composed of an element or a compound?

2007-01-16 09:44:08 · 2 answers · asked by ashesanne 2

Identify the products and write a balanced equation for the following neutralization reaction. It will be a double displacement reaction with water as one of the products.
HCl(aq) + Ca(OH)2(aq) ------->

2007-01-16 09:37:19 · 5 answers · asked by Anonymous

Predict the freezing point (in Celsius) of a solution of 5.0 g phenol in 100 g water. The Kf of phenol is 7.40 degrees Celsius (kg)/mole. I am suppose to use1 this equation: M=(Kf * g) / (ΔTf * G), but I need to solve for Tf instead of M. I really need some help on how to get started with this problem. If anyone could help, your response would greatly be appreciated. Thanks.

2007-01-16 09:33:03 · 2 answers · asked by maya 1

2007-01-16 09:19:41 · 1 answers · asked by Anonymous

2007-01-16 09:18:17 · 9 answers · asked by Casey D 1

2007-01-16 09:08:21 · 2 answers · asked by Lola 1