Chemistry (Science & Mathematics) - September 2006

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semiconductors?

1. what is semiconductors

2. why metals are good conductors of electricity while semiconductors have relatively poor conductivity?

3.why plastic deformation(eg. cold rolling) and alloying (eg. in stainless steel) affect the electrical resistivity of metals?

4. what is the difference between intrinsic and extrinsic semiconductor?

5.what is the role of doping in the electrical conductivity of semiconductors

6.what's the difference between n-type and p-type semiconductor?

7.what cause the different resistivity values of metals?

8.why semiconductor possess different electrical resistivity?what is the most dominating factor?

9.why there's a large difference in electrical resistivity between metals and semiconductors?

2006-09-19 21:25:17 · 6 answers · asked by lkamh 2

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what are polymers?

2006-09-19 21:21:26 · 16 answers · asked by van 1

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selling price for 1 oz of 999silver?

2006-09-19 21:14:13 · 1 answers · asked by lim wei da 1

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what is an electron?

2006-09-19 20:06:18 · 28 answers · asked by pandu murali 1

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what are the limitations of using flame tests to identify ions present in solution?

2006-09-19 19:46:57 · 2 answers · asked by Elisha W 1

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Is it possible for you cars keyless remote to heat up enough to burn you?

i saw my friend got in a really bad fight with his parents, ive never seen him get that mad before.
Out of nowhere he yells out ouch and throws his keys on the ground. A little later I saw burns
marks on his hands that looked like key marks and he said it was probably his keyless remote because it was acting weird earlier. Its just dont see how a keyless remote can heat your keys so much it burns you.

2006-09-19 19:30:23 · 4 answers · asked by Mr M 1

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Moles - Number of particles and Number of atoms.?

I know multiplying the number of moles by avogadro's number gives me the number of particles in that mixture. I am told I need to multiply this by the number of different elements inside, eg. C6H12 's number of particles has to be multiplied by 18 in order to get the number of atoms.

2006-09-19 19:26:49 · 6 answers · asked by Emma Lee 2

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what is lactic acid and how does it work?

also what are its effects on humans? from my understanding so far, it is used in foods as flavoring.

2006-09-19 18:49:35 · 3 answers · asked by Anonymous

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what is air moliculs?

2006-09-19 18:18:27 · 3 answers · asked by king i 1

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magnitude question?

a solution has a pH of 3 and another solution has a pH of 5
what is the difference in magniture of (H+) in the two solutions?

2006-09-19 17:58:17 · 1 answers · asked by Anonymous

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i need an electron configuration chart?

i need a chart from the element H (hydrogen #1) trough Sc (Scandium# 21) if anyone could help me with that i would really appriciate it.. :)

2006-09-19 17:44:27 · 3 answers · asked by The One 2

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what are the exact reactions in combustion of c to produce co2 are all exothermic?

CO2 + C = Co is an endothermic reaction

2006-09-19 17:15:22 · 3 answers · asked by rds7772000 2

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melting point and recrystalisation?

1- Benzoic acid(m.p 121 c ) is contaminated with 5% of 9,10-dimethylanthracene( m.p 1821 c ) . will the m.p of benzoic acid be above or below 121 c . why ?

2- two substance of practically equal solubility are present in the same amounts in a mixture . can they be separated by recrystallisation ? explain .

2006-09-19 17:07:17 · 3 answers · asked by Anonymous

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What is known as the 'King of Chemicals'?

2006-09-19 17:00:36 · 14 answers · asked by ben r 1

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combustion of c to pfroduce co2?

2006-09-19 16:52:35 · 3 answers · asked by rds7772000 2

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R Monster take one day at a time cause not possible to take two days at a timeRRRRRaAAAAAAAA!!!!?

RRRRRaAAAAAAAA!!!!

2006-09-19 16:17:00 · 5 answers · asked by AAAHH!! A MONSTER!!! 1

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What is Air?

is it a compound, heterogeneous mixture, element or homogeneous mixture?

THX!

2006-09-19 16:03:25 · 10 answers · asked by ryguy2303 3

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Is plutonium now considered to be a minor element?

2006-09-19 15:44:39 · 3 answers · asked by wild_turkey_willie 5

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Although temperature and heat are closely related, they are not the same. How are they not the same?

2006-09-19 15:44:31 · 7 answers · asked by melissa 1

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what element that forms an oxide that can be reduced by carbon?

2006-09-19 15:43:41 · 1 answers · asked by Anonymous

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Law of conservation of Mass?

After a fire, the ashes have less mass and take up less space than the trees and vegetation before the fire. How can this be explained in terms of the Law of Conservation of Mass?

2006-09-19 15:38:28 · 10 answers · asked by Anonymous

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