Chemistry - April 2007

2007-04-30 10:25:16 · 4 answers · asked by adrian 1

I've noticed that with organic compounds, as a molecule gets bigger (more carbon atoms), its melting and boiling point increases. This has to do with intermolecular forces.

Why does it require more energy to break the intermolecular bonds of a bigger molecule? Aren't the dispersion (intermolecular fores) the same for both molecules?

C-C-C-C --- C-C-C-C (dispersion between 2 butane molecules)

C-C-C-C-C-C-C-C --- C-C-C-C-C-C-C-C (dispersion between 2 octane molecules)

Can someone please explain?

2007-04-30 10:24:25 · 2 answers · asked by Dave H 2

I honestly have no idea whats going on in this question... but here it is.
zn(s)+cu+2->zn+2+cu(s)
an electrolytic cell based on the reaction represented aboce was constructed from zn and cu half-cells. The observed voltage was found to be 1.00volts instead of standard cell potential, E0, of 1.10volts. which of the following could correctly account for this observation?
1. the cu electrode was larger than the zinc electrode
2. the zn+2 electrolyte was zn(no3)2, while the cu+2, electrolyte was cuso4
3. the zn solution was more concentrated than cu solution
4. the solution in the half cells had different volumes
5. the salt bridge contained kcl as the electrolyte..

PS. cu+2 OR zn+2 means that its an ion with 2+ charge

THANK YOU

2007-04-30 10:13:47 · 1 answers · asked by DENIS C 1

What causes static electricity?

A. too many protons
B. too many electrons stick
C. materials are overly charged

2007-04-30 09:26:39 · 1 answers · asked by Anonymous

I'm having trouble with the last 5 problems on my homework. Any help would be greatly appreciated!

Label each of the following as a combination, decomposition, single or double replacement. Then complete the reactions and balance.

NaI+Br2 =
NiSO4•7H20=
HNO3+Ca(OH)2=
Cu+Zn(NO3)2=
MgO+CO2=

Thanks again!!!!

2007-04-30 09:20:06 · 1 answers · asked by Stephanie S 1

In an aqueous solution of an ionic salt, the oxygen atom of the water molecule is attracted to the

1. negative ion of the salt, due to oxygen's partial positive charge
2. negative ion of the salt, due to oxygen's partial negative charge
3. positive ion of the salt, due to oxygen's partial positive charge
4. positive ion of the salt, due to oxygen's partial negative charge

2007-04-30 09:05:30 · 1 answers · asked by damanja20 1

here is my question, how does soap work? i know its something to do with hydrogen bonds, but if someone could give me a good explanation id be so happy! :)

2007-04-30 08:40:15 · 4 answers · asked by Elizabeth M 2

How long will it take for 75.0% of a 0.00850 mg sample of radioactive iron-59 to decay? The half-life of iron-59 is 45.10 days, so give your answer in days.

2007-04-30 07:59:36 · 1 answers · asked by a 1

This method of heat transfer is caused by atomic collisions:

A. conduction
B. convection
C. radiation

2007-04-30 07:56:49 · 3 answers · asked by Anonymous

I dont expect you to know this....

2007-04-30 07:42:56 · 5 answers · asked by Airy. 1

The purpose of an insulator is to

A. slow heat transfer
B. accelerate heat transfer

2007-04-30 07:42:07 · 7 answers · asked by Anonymous

True or False?
How about this...
Does the Lewis structure for CO2 show that the molecule contains TWO double bonds? Yes or No?

2007-04-30 07:39:14 · 3 answers · asked by Anonymous

Is it K+?

2007-04-30 07:35:41 · 2 answers · asked by Anonymous

2007-04-30 06:57:25 · 5 answers · asked by Anthony L 1

For 1.3 mole of the radioactive isotope chromium-51, half-life = 27.8 days, how many disintegrations have occurred after 18 minutes?

Enter a numeric answer only do not include units

2007-04-30 06:49:16 · 1 answers · asked by Anonymous

I forgot in my chem. class and my teacher was kinda a crackpot!!

2007-04-30 06:43:05 · 8 answers · asked by Anonymous

What would be the anode reaction of the electrolysis of molten potassium hydroxide?

2007-04-30 06:39:15 · 2 answers · asked by calculusgirl1979 2

Write the net ionic equation for the reaction of silver nitrate with sodium chloride.

I am stuck on this one.

2007-04-30 06:38:09 · 2 answers · asked by calculusgirl1979 2

I am having trouble with finding any thorough information on Citric Acid.
Please answer by 10:00 PM Pacific!
Thanks in advance. :)

2007-04-30 06:35:54 · 5 answers · asked by DTSL 2

ion when pH =4 (show work). What does the result of this calculation indicate about the concentration of the hydronium ion in a solution that has a pH of 2 compared to a solution with a pH of 4?

2007-04-30 06:29:31 · 2 answers · asked by darkraven_222000 1

(cont to the Q) today?

2007-04-30 06:27:44 · 2 answers · asked by nalatwolf 1

concentration in the solution. In what part of the pH scale must the pH of this solution lie?

2007-04-30 06:26:17 · 1 answers · asked by darkraven_222000 1

Reaction: 2HCI + Ca(OH)2-----> 2H2O + CaCl2

2007-04-30 06:18:31 · 4 answers · asked by Anonymous

1 nitric acid
2 hydrochloric acid
Why and please show the equation!!!

2007-04-30 06:10:19 · 1 answers · asked by Julie 1

It is named after the German physicist Wilhelm Rontgen. A roentgen is the amount of radiation required to liberate a pair of positive and negative charges from atoms of one electrostatic unit of charge in 1.00 cm3 of air at standard temperature and pressure. This corresponds to the generation of approximately 2.08 × 109 ion pairs. A dose of 500 R in five hours is lethal for humans.



If X radiation ionizes 23.0 × 1013 atoms per cemtimeter cubed, what is the ionizing intensity of the radiation measured in roentgens ?

2007-04-30 05:14:32 · 1 answers · asked by Anonymous

so the ratio of rates at two different times is given by R(t1)/R(t2) = N(t1)/N(t2).
For nuclear decay the rate is ofen is expressed in units of counts per unit of time.


A chemists determines that a sample of petrified wood is 3.50 X 103 years old. What is the rate of decay, in counts per minute per gram, of carbon-14 in the sample? The decay rate of carbon-14 in wood today is 13.6 counts per minute per gram, and the half life of carbon-14 is 5730 years.

2007-04-30 05:13:23 · 2 answers · asked by Anonymous

2007-04-30 05:09:10 · 2 answers · asked by amandac 3

boilinng temprature of primary alkyl ammine is higher than corresponding hydrocarbons , alkyl halides but lower than corresponding alcohols
eg: methan < methyl choride

2007-04-30 04:31:49 · 1 answers · asked by sonu 1

The Ksp of silver Bromide is 4.1x10^(-13). Will a precipitate form if 25.0mL of .0345M silver nitrate solution is mixed with 25.0mL of 3.63x10^(-4)M sodium bromide solution?

I'm clueless on this?

2007-04-30 04:03:26 · 4 answers · asked by Anonymous

If a 3.30 lb cat absorbs 1.40 × 10−5 KJ of radiation, how many rads did this cat absorb?

2007-04-30 04:02:51 · 3 answers · asked by guitarx313 1