Chemistry - June 2007

please help i cant find anything

2007-06-01 15:28:11 · 1 answers · asked by critic2012 1

please help i cant find anything

2007-06-01 15:27:27 · 1 answers · asked by critic2012 1

2007-06-01 12:56:26 · 13 answers · asked by christina E 1

A quick answer needed!

2007-06-01 12:49:31 · 2 answers · asked by hallofamer20 2

Can someone reconcile these statements for me?

1. From http://en.wikipedia.org/wiki/Bronze
"With the exception of steel, bronze is superior to iron in nearly every application."

2. From http://en.wikipedia.org/wiki/Three-age_system
[People switched from the Bronze Age to the Iron Age because] "no one would have wanted to use bronze tools if there had been iron ones around instead."



Maybe the second statement should refer to steel instead of (pure) iron. Did the Iron Age start with the use of pure iron, or did it start with steel? If it started with pure iron, then how was it an advantage over bronze? And if it started with steel, then shouldn't it be called the Steel Age instead of the Iron Age?

2007-06-01 12:26:24 · 5 answers · asked by Anonymous

1. What is "cracking" and why is it important?

Cracking mean hydrocarbons in these fractions are broken into smaller fragments in a technological process.

i explain what is cracking, but i don't know how importand is it.


2.What is “reforming” and why is it important?

i don't know how to do No.2 , can someone help me

please...

That unit is talking about hydrocarbons

2007-06-01 12:17:31 · 1 answers · asked by Anonymous

2007-06-01 11:47:09 · 9 answers · asked by Anonymous

If so, does the evaporation increase A LOT MORE in the summertime?

2007-06-01 11:20:31 · 5 answers · asked by wisemancumth 5

2007-06-01 11:12:22 · 5 answers · asked by Amanda 2

2007-06-01 10:24:09 · 4 answers · asked by Anonymous

Gasoline is a blend of hydrogen and oxygen. Calculate the volume of carbon dioxide, at 300 Degrees C and 110 KPa, that will pass through the muffler of a car during combustion of a full tank (50.0 kg) of gasoline. Assume the chemical formula of gasoline is C7H16.
Balance chemical equation is: C7H16 + 11 O ==> 7 CO2 + 8 H2O
Then I know I have to convert temperature to Kelvins : 300 + 273 = 573k
Then convert given mass to moles 50.0 * 10^3 g * 1 mol / 44.0 g CO2 = 1.136 mol
Then 1.136 * (and now I am lost) Any help would be appreciated.

2007-06-01 10:19:53 · 3 answers · asked by flowers4eden 1

What are other iodide indicators rather than starch?How do u prepare it ?What is the color change?

2007-06-01 10:13:03 · 2 answers · asked by sadeghchemical 1

I am having a problem with a question in Chemistry.
When ammonia burns in oxygen at 800 degrees C over a platinum catalyst, the products are nitric oxide and steam. Calculate the volume of nitric oxcide that is produced if 1.20 * 10 to the power of 5 L of oxygen is used u[ in the reaction.

The balanced equation is: 4NH3 + 5O2 ==> 4NO + 6H2O
I think the next step would be to use volume ratio to find required volume: V of O2= 1.20 * 10^5 L O2 * 4 vol of NH divided by 5 vol of O2 and you get the answer.
I am really not sure though if this is correct anbd would appreciate some help with this. Thanks!

2007-06-01 10:03:03 · 1 answers · asked by flowers4eden 1

if you run a chemical equation at, lets say a tempurature of 25o C, what would it mean to decrease it by a factor of 4?

2007-06-01 09:48:49 · 2 answers · asked by maxxuss 1

the reaction: 7H2O2 (aq) + N2H4 (g) ---> 2HNO3 (g) + 8H2O (g)



If a chemist starts with 110.0 grams of H2O2 and an excess of N2H4, what volume of water vapor will be produced at a temperature of 341oC and a pressure of 2.1 atm?

2007-06-01 09:14:52 · 2 answers · asked by Anonymous

1. How many grams of KCl are in 10ml. of a .10M solution

a) 1.0 * 10 to the -3g
b) 0.013g
c) 0.075g
d) 1.0g
e) 75g

how is this solved

2. Which of the following substances would conduct electricity best when in liquid form

a) C6H12O6
b) H2O
c) KF
d)H2S
e) CO2

3. Which of the following compounds contains a polyatomic ion

A) KBr
b) Na2So4
c) C6H12O6
d)CO2
e) LiCL

2007-06-01 07:31:51 · 1 answers · asked by Anonymous

2007-06-01 07:00:03 · 2 answers · asked by money money 3

The following reaction is taking place: 13.6 grams of Lithium Carbonate reacts with 12.2 grams of sodium nitrate. Write out the balanced equation and show work to prove which reactant is the limiting reactant.

2007-06-01 06:02:36 · 4 answers · asked by Ethan 1

I need to know the follow about these compounds.
-Type of bond
-Electro negativity Calculation
-Electron Dot Configuration

Cl2 (small 2 under the L)

CO2(small 2 under the O)

2007-06-01 05:59:34 · 2 answers · asked by Ethan 1

True or false, and explain please.

A catalyst causes a reaction rate to increase by lowering the total amount of energy produced.

The larger surface area to volume ratio, the higher the reaction rate for chemical reactions.

Thanks for any help!

2007-06-01 05:54:24 · 4 answers · asked by Ethan 1

a blood analysis shows a vitamin C concentration of2.0mg/100 ml of blood. how many grams of vitamin C are there in 5.0 L of this blood

2007-06-01 05:53:27 · 7 answers · asked by Anonymous

I have a very vague understanding of how vitamins and minerals break down and how more complex, natural minerals and vitamins work.

What i'm wondering, is, Can I get an explanation of the vitamin relationships that occure naturally in fruit? For example this vitamin in an orange works with that vitamin also in the orangs and others, so they have a relationship dynamic that is complex and more beneficial than the same vitamins that are synthetically produced. I would really like to understand how this works and how my body recieves and processes the natural complex relationships better than synthetic or pill form.
I hope that makes sense =P

2007-06-01 05:42:07 · 2 answers · asked by youthfultalent 3

chemistry

2007-06-01 05:32:19 · 5 answers · asked by rb_1213 1

As I understand it, O3 that is released at ground level is heavier than air, so how did it get to the stratosphere?? Does the Ozone layer regenerate and if so, how?
Would the effect of gravity be less, at such a distance from the earth....?

2007-06-01 05:29:02 · 4 answers · asked by mant 2

for free or for money . a legit clinical lab in the los angeles area

2007-06-01 05:20:42 · 3 answers · asked by chickengame 1

in 1mL of 10^-4 M (mol/L) H2SO4 solution there are:

1,2*10^17 H^+ ions

This is the correct answer. I didn't got that

2007-06-01 05:14:50 · 5 answers · asked by Anonymous

2007-06-01 05:06:38 · 2 answers · asked by hasan z 1

Solar cell A uses a semiconductor with a band gap of 1 eV. Solar cell B uses a semiconductor with a band gap of 2 eV. Either cell is thick enough to absorb all the light above its band gap. Both cells can work simultaneously with one on top of the other to operate more efficiently in a small space. Which cell has to be on top (first to receive the sunlight) for both to work simultaneously, and why?


I thought of the problem in two ways. The first was that the one w/ the larger band gap is an insulator and hence should be placed on the bottom b/c if it were on the top the one with the smaller band gap on the bottom wouldn't get any energy. The second way was that the one with the larger band gap should be on top because it could only absorb 2 eV and above, thus energy less than 2 eV would "pass through" to the bottom one so that energy between 1 and 2 eV could be utilized.

2007-06-01 04:51:48 · 2 answers · asked by CH 1

2007-06-01 04:48:59 · 0 answers · asked by Anonymous

chemistry

2007-06-01 04:45:59 · 10 answers · asked by rb_1213 1