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Author Topic: CHEM AND BIO HELP AND TIPS HERE  (Read 354093 times)

Offline Moonlyte

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1665 on: May 23, 2010, 05:24:30 pm »
Quote from: Ivo on May 23, 2010, 04:47:38 pm
Can someone tell me what the role and what hormones for menstrual cycle.  

Also, stuck on this question:



This is the ans from marking scheme:

Fertility drugs: FSH causes ovaries to produce more eggs, thus increasing chance of fertilization.

Chemical: contraceptive pill prevents FSH release. This prevents egg development so ovulation is prevented.
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Offline Syed Kazim

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1666 on: May 23, 2010, 05:26:17 pm »
Quote from: Burhan.arshad on May 23, 2010, 05:23:11 pm
i am asking about ethers.....not esters.....

Oops. Sorry, I misread.  :-[
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Offline Moonlyte

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1667 on: May 23, 2010, 05:26:23 pm »
Quote from: Burhan.arshad on May 23, 2010, 05:23:11 pm
i am asking about ethers.....not esters.....

Simple, symmetrical ethers can be formed by the acid-catalyzed condensation of two molecules of an alcohol.  For example, diethyl ether will form is ethanol is treated with concentrated sulfuric acid.
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Offline Helium

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1668 on: May 23, 2010, 05:27:28 pm »
Quote from: Raywin on May 23, 2010, 05:18:16 pm
The synthetic hormones "over-grow" these weeds and eventually these weeds die. thts all.. :)


So if synthetic plant hormones over grow the weed and kill them in what
way is this similar to auxin ???
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Offline Syed Kazim

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1669 on: May 23, 2010, 05:28:14 pm »
Quote from: Moonlyte on May 23, 2010, 05:24:30 pm
This is the ans from marking scheme:

Fertility drugs: FSH causes ovaries to produce more eggs, thus increasing chance of fertilization.

Chemical: contraceptive pill prevents FSH release. This prevents egg development so ovulation is prevented.


But in the Mary Jones textbook on Page 81, Chemical method is described as using chemicals. The method where hormones are used is called the Hormonal method.
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Offline Burhan.arshad

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1670 on: May 23, 2010, 05:29:34 pm »
Quote from: Moonlyte on May 23, 2010, 05:26:23 pm
Simple, symmetrical ethers can be formed by the acid-catalyzed condensation of two molecules of an alcohol.  For example, diethyl ether will form is ethanol is treated with concentrated sulfuric acid.

can u explain in more details?
with equations?
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Offline Moonlyte

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1671 on: May 23, 2010, 05:31:01 pm »
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Offline Moonlyte

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1672 on: May 23, 2010, 05:31:59 pm »
Quote from: Moonlyte on May 23, 2010, 05:31:01 pm
I actually got the answer from the follwoing site: http://www.ferris.edu/htmls/academics/course.offerings/balandap/Organic/CHEM124/Problems/Ethers_and_epoxides_ANS.htm

it has equations.

just press ctrl+F and type formation of ethers....its sumwhere in the middle of the page...
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Offline Burhan.arshad

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1673 on: May 23, 2010, 05:34:16 pm »
Quote from: Moonlyte on May 23, 2010, 05:31:59 pm
just press ctrl+F and type formation of ethers....its sumwhere in the middle of the page...

Thanks
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Offline Syed Kazim

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1674 on: May 23, 2010, 05:36:26 pm »
Quote from: Burhan.arshad on May 23, 2010, 05:29:34 pm
can u explain in more details?
with equations?

Ether is a class of organic compounds that contain an ether group — an oxygen atom connected to two alkyl or aryl groups — of general formula R–O–R. A typical example is the solvent and anesthetic diethyl ether, commonly referred to simply as "ether" (CH3-CH2-O-CH2-CH3). Ethers are common in organic chemistry and pervasive in biochemistry, as they are common linkages in carbohydrates and lignin.

Try going to the following links to find what specific areas you want answers in.

Chemical properties of ether
Preparation of ethers
Friedel craft reaction
Halogenation of ether
Hydrolysis of ether
Oxidation of ether
Peroxide formation
Ring substitution in aromatic ethers
Salt formation by ether
Williamson synthesis
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Offline Moonlyte

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1675 on: May 23, 2010, 05:36:47 pm »
Quote from: Syed Kazim on May 23, 2010, 05:28:14 pm
But in the Mary Jones textbook on Page 81, Chemical method is described as using chemicals. The method where hormones are used is called the Hormonal method.

hmmm...maybe they add chemicals which behave like estrogen and progesterone in the pills....
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Offline Moonlyte

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1676 on: May 23, 2010, 05:37:13 pm »
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Offline SoONa

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1677 on: May 23, 2010, 05:40:29 pm »
heyy .. exams 2mrrw wish everyone luckk ..

my question is from may/june 2003 it sayss

a)explain why in some parts of the world, not enough food is available to feed the people living there . (10 marks)

b) describe the use of hormones in foood production

thannks in advance !!!
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Offline Syed Kazim

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1678 on: May 23, 2010, 05:41:39 pm »
Quote from: Moonlyte on May 23, 2010, 05:36:47 pm
hmmm...maybe they add chemicals which behave like estrogen and progesterone in the pills....

Hmm... possible. Here are the exact wordings:

Quote
Chemical methods use chemicals called spremicides, which kill sperm. They are best used in combination with another method. For example, spermicides may be inserted into the vagina with a cap.

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Offline thenewkid™

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1679 on: May 23, 2010, 05:44:26 pm »
Quote from: Moonlyte on May 23, 2010, 05:36:47 pm
hmmm...maybe they add chemicals which behave like estrogen and progesterone in the pills....
chemical method:
spermicides: a gel or foam,kills in the vagina, should be used with a diaphragm or a condom
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