Chemistry - June 2007

Calculate the energy difference between the two quantum states involved with this absorption.

2007-06-08 14:41:56 · 1 answers · asked by Anonymous

I'm doing a year 10 science experiment, and i've been searching all over the internet to find out, yet I can't. Can someone (with sources included) answer my question?
My experiment is to use different liquids and place the same ammount of chewing gum into each and measure visually how much decay has occured.

2007-06-08 14:39:24 · 14 answers · asked by Powerbook 2

Wonder if anyone knows how to create a cocktail glue out of DIY store items that apply on wall or paper surface and sticks like non permanent sticker...again and again.

2007-06-08 13:18:15 · 1 answers · asked by Gomezz 2

This is part of the physical chemistry questions related to the conductivity of the electrolyte solutions:
Part a: A solution of KCl with a known conductivity of 0.012886 S/cm (per ohm per cm) has a resistance of 24.96 ohms when measured in a conductivity cell. A sample of the water used to prepare the solution had a resistance of 1 x 10^6 ohms in the same cell. What is the cell constant?

Part b: A solution of 0.0100 M acetic acid prepared using the same water as in part a had a resistance of 1982 ohms when measured in the same cell. What is the molar conductivity of the acetic acid?

2007-06-08 11:51:00 · 2 answers · asked by richard 1

A strong base that accepts a proton becomes a ________ conjugate acid.

A. weak
B. strong

2007-06-08 10:40:34 · 2 answers · asked by marco10906 1

a) How many mL of 0.500M silver nitrate solution should be added to 50.00mL of 0.0700M potassium chromate solution, assuming 100% yield?


b) If only 95.0% yield is assumed, how many mL of silver nitrate solution should be added to obtain 1.000g of silver chromate?

Thanks in advance.

2007-06-08 10:22:16 · 1 answers · asked by gym guy 2

2007-06-08 10:11:08 · 9 answers · asked by MICHAEL B 4

I have to to an Etg urine test. will it be positive. how quickly does the etoh cook out.

2007-06-08 09:51:11 · 3 answers · asked by terwilligernancy 1

i know you dont lose alot but the more the better

2007-06-08 09:28:40 · 5 answers · asked by Anonymous

soulubilty of acetanilide in recrystalizing solven is 5.0 mg per mL at 10 C.

a) calculate the maximum % recovery assuming 15 mL recrystallizing solution filtered at 10 C.

2007-06-08 08:48:42 · 1 answers · asked by goofy 2

2007-06-08 08:43:24 · 1 answers · asked by J 2

2007-06-08 07:31:53 · 7 answers · asked by random panda ! 2

(iii) complete this sentence by choosing the correct ion from the box

H+ NH4+ NO3- 02- OH-

THE ION THAT MAKES SOLUTION ACIDIC IS ?

Complete thsi sentence about crude oil ?

crude oil is mainly a mixture of compounds called ...................... which contain carbon and hydrogen only.

complete each sentence by choosing the correct words from the box.

condesation
distillation
evaporation
melting
sublimation

the main process takeing place at A is .........................................
the main process takeing place at B is .....................................
this method of separating crude oil is called ....................................


complete this sentence by crossing out the word in each box this is wrong. the first one has been done for you.

this method of separating crude oil works because the smaller the molecules are, the high or lower their boiling point and the more or less volatitle they are.

2007-06-08 07:17:06 · 4 answers · asked by abdull 1

is it true that it is made from animal fat (pigs) and if so what do people that are vegans use or those who don't use pork products for religious reasons?

2007-06-08 07:12:49 · 7 answers · asked by AH SHIIII... 2

a. can not dissolve any more solute in that quantity of solvent
b. can accomodate any amount of solute

2007-06-08 06:54:36 · 5 answers · asked by Anonymous

a. Molarity
b. Molality
c. Parts Per Million (PPM)

2007-06-08 06:53:52 · 4 answers · asked by Anonymous

A. a conversion factor used in solution stoichiometry
B. used with calculations of properties such as boiling point elevation.
C. to express small concentrations

2007-06-08 06:53:00 · 4 answers · asked by Anonymous

a. they cannot be excreted through the kidneys
b. they are not water soluble
c. they are stored in our body fat
d. all of the above

2007-06-08 06:51:53 · 3 answers · asked by Anonymous

450 ml of .8M NaOH and .36 moles. How many grams of NaOH are in this solution?

2007-06-08 06:29:22 · 4 answers · asked by pirateprincess 2

N2S3

If the molar mass of the compound is 248 g/mole what is the molecular formula.

2007-06-08 06:25:20 · 2 answers · asked by pirateprincess 2

(1) the proton

(2) the neutron

(3) the nucleus

(4) the electron

2007-06-08 06:25:06 · 13 answers · asked by Anonymous

If 55 calories of heat is absorbed by 1200 grams of water at 25 celcius what will be the final temperature of the water?

2007-06-08 06:22:28 · 4 answers · asked by pirateprincess 2

Hi, I really need help with this its very confusing since I cant identify the weak acid and its conjugate base...I think its H3PO4 and H2PO4- but there's no initial concentration of H3PO4 so how do I work this out:

A buffer is prepared by adding 150mL of 1.0M NaOH to 250mL of 1.0M NaH2PO4. How many moles of HCl must be added to this buffer solution to change the pH by 0.18 units?

Please help, any input would be very much appreciated.

2007-06-08 06:20:46 · 3 answers · asked by Anonymous

(1) It is made of more than one element?

(2) it forms crystles when its frozen?

(3) it contains oxygen?

2007-06-08 06:15:43 · 9 answers · asked by Anonymous

Not cola obviously, but bicarbonate or whatnot that they use to adjust the pH. Can that hurt you? What if you swallowed pool water while swimming? Got in in youir eyes/ears?

2007-06-08 06:14:58 · 4 answers · asked by Anonymous

Question:
The first six ionization energy for the elements X Y are shown in the element table below. Identify possible names or Z numbers for the elements X and Y? (Note: the ionization energy is not given!)

Table:
http://img130.imageshack.us/img130/5373/tablezy8.png

2007-06-08 06:09:31 · 2 answers · asked by Reed 1

I heard that if you leave a water bottle in your car, the sun's UV rays can somehow react with the plastic bottle, and this reaction emits certain chemicals into the water in this bottle. I tried to find some information on this online, but had no luck. Anyone out there know anything about this?

2007-06-08 06:00:00 · 10 answers · asked by SueDogg 2

All of the KBr that will dissolve in a solution has dissolved, and several undissolved crystals remain on the bottom. The solution is

a. saturated
b. supersaturated
c. unsaturated

2007-06-08 05:51:22 · 6 answers · asked by Anonymous

If the amount of a dissolved solute in a solution at a given temperature is greater than the amount that can permanently remain in a solution at that temperature, the solution is said to be

a. saturated
b. unsaturated
c. supersaturated

2007-06-08 05:50:43 · 4 answers · asked by Anonymous

I've got a couple of questions on my ap chemistry final, that I need some help with. I know this is immoral, but I'm desperate!

Which is not correct?
a. 1000mg=1gram
b 100cm=1m
c100m=1cm
d 1000uM=1millijoule

2007-06-08 05:39:28 · 8 answers · asked by blah 1