Chemistry - January 2007

This is a problem in my textbook:
Consider the reaction W + 3Y = 2N + 4Z
A solution was prepared by mixing 100.0 mL of 8.04 x 10^-3 M W and 200.0 mL of 4.63 x 10^-3 M Y. After the system had come to equilibrium, the absorbance, A, of the solution was measured at a wavelength (600nm) where only Z absorbs light. The value of A (absorbance) was found to be 0.422.

The following data were also collected for known solutions of pure Z at 600nm:
[Z]-------------------A (absorbance)
2.00x10^-4---------0.100
5.00x10^-4---------0.240
8.00x10^-4---------0.390
18.0x10^-4---------0.880

I just don't know where to start with this one. Not even sure I understand what it's asking me to do! Thanks for the help.

2007-01-30 20:07:52 · 2 answers · asked by thesekeys 3

I can't mix with salt because salt is corrosive, please help me

2007-01-30 19:17:59 · 4 answers · asked by Bruce B 1

2007-01-30 19:14:01 · 2 answers · asked by s s 1

And Also....

What is the shape of the molecules in saturated & unsaturated fats?

2007-01-30 19:04:39 · 5 answers · asked by ummm.... 1

1- [Conservation of Mass Problem]
Some iron wire weighing 5.6g is placed in a beaker & covered with 15.0g of dilute hydrochloric acid.The acid reacts w/ the metal & gives off hydrogen gas,which escapes into the surrounding air. After reaction the contents of the beaker weighs 20.4g.What's the mass of Hydrogen gas produced by the reaction?

2- A solid cylinder of iron of circular cross section w/ a radius of 1.500cm has a ruler etched along its length.Whats the volume of iron contained between the marks labeled 3.10cm & 3.50cm? The Volume of a cylinder is "pi"r^2 L. pi=3.1416,r=radius, L=length.

3-Using Scientific Notation Convert:
a. 6.20 km to m
b. 2.54 cm to m
c. 1.98 ns to s
d. 5.23 "micro"g to g
-------
1- I got .2 g, but IDK if I did it right.
2- I think it's 2.82744 but w/ correct Significant Figures = 2.8
3- ? IDK

*Can someone please check to see if I'm on the right track & also explain the concepts to me. I would really appreciate it! Thanks! = )

2007-01-30 18:47:21 · 2 answers · asked by Miss*Curious 5

2007-01-30 18:29:14 · 2 answers · asked by Rajchem 2

2007-01-30 18:19:22 · 4 answers · asked by macfaro 1

2007-01-30 18:16:10 · 5 answers · asked by destroyer 1

2007-01-30 17:26:37 · 1 answers · asked by Courtsie2004 m 1

2007-01-30 17:21:54 · 1 answers · asked by Courtsie2004 m 1

How does temperature (proportional to average speed of the molecules) affect the pressure? Compare samples in the same size container at the two differnt speeds.

Any info would be of great help. Thanks to all of you ahead of time

2007-01-30 16:39:31 · 4 answers · asked by Anonymous

2007-01-30 16:14:16 · 3 answers · asked by amrita k 1

2007-01-30 15:50:12 · 15 answers · asked by ? 2

2007-01-30 15:38:03 · 6 answers · asked by teck kim 2

What the hell is an ion i fell asleep in class and wikipedia is even more confusing?also whats a valence electron?

2007-01-30 15:33:36 · 1 answers · asked by light within darkness 2

2007-01-30 15:08:45 · 3 answers · asked by little.clown 2

Na2O, BaO, CO2, N2O5, P4O10, SO3.
Please, Im lost!

2007-01-30 15:07:48 · 1 answers · asked by Me 3

Given the following data:


2O3 → 3O2 DH = −427 kJ


O2 → 2O DH = +495 kJ


NO + O3 → NO2 + O2 DH = −199 kJ


Calculate DH for the reaction


NO + O → NO2

I know that I have to manipulate the equation but I am getting some off answers. Can anyone point me in the right direction?

Someone answered me saying that Oxygen is not a monotomic element and yes i know that -- thats why the reaction is + it requires work. I need more direction than that.

2007-01-30 15:07:10 · 1 answers · asked by Shannon M 1

I know I learned this at some point...
I only have one for each, one of those fill-in chart type things.

2007-01-30 15:06:05 · 3 answers · asked by Anonymous

Im competely lost!! HELP! ME UNDERSTAND!

Ocatane, C8H18 is a desirable component of gasoline. Octane burns cleanly and prevent engine knocking in automobiles. The thermochemical equation showing the combustions of octane is shown below.
C8H18(L)+25/2 O2(g)--> 8CO2(g)+ 9H2O(g)
then is says: triangle thing H = -5472kJ

1. What is the heat reaction for the combustion of octane in Kcal/mol ? (4.184 J= 1cal)

2.Before octane combusts, what type of energy is present in the system?

3. After octane combusts, what type of energy is present in the system?

Im so lost! Any info on this prob would be wonderful!!!!

2007-01-30 15:05:09 · 3 answers · asked by Tracey Lee ♥ 2

Im Stumped with this problem:

Calculate the standard enthalpy change in kJ for the production of 14.6 g of Fe(s) from a reaction where the reactants and products are:

reactants: Fe2O3 (s) CO (g)

products: Fe(s) CO2 (g)

2007-01-30 15:03:11 · 4 answers · asked by Jessica R 1

I have recently just done a experiment that has to do with mass, capacity, weight and volume. I filled the beaker with 100ml of water. It turned out to be 90.4 grams after I subtrated the weight of the beaker. Then I tried doing it with 200ml of water. I got 197gram after I subtracted the weight of the beaker. Shoudn't it be 180grams instead of 197 cause it's doubled? I made sure I used the triple beam balance correctly and I used the same beaker. Basically what im wondering is, does it have to do with the particle theory? like what happened to the particles?

2007-01-30 15:02:48 · 5 answers · asked by Matt 2

2007-01-30 14:39:48 · 3 answers · asked by Anonymous

an atom that loses electrons has a negative charge

2007-01-30 14:24:23 · 11 answers · asked by Anonymous

Suppose an aqueous solution contains both sugar and salt, can you seperate either of these solutes fron the water by filtration ?

2007-01-30 14:24:20 · 4 answers · asked by grace is good for you 2

They must be real gases existing on earth or in stellar clouds.

2007-01-30 14:20:51 · 3 answers · asked by chijliak 1

Please answer this question.

2007-01-30 14:17:28 · 9 answers · asked by Your moms daddy 2

silicon tetrachloride + water --> silicon dioxide + hdrochloric acid

Aluminum oxide + sulfuric acid --> aluminum sulfate water

carbon tetrahdride + chlorine --> carbon tetrachloride + hdrochloric acid

Thanks!

2007-01-30 14:16:30 · 1 answers · asked by SUnny S 1

Can you give me an example of a molecule made up of the same element, and a molecule made up of two different elements?

2007-01-30 14:15:33 · 3 answers · asked by Anonymous

2007-01-30 14:15:14 · 1 answers · asked by Taylor S 2