Author Topic: Chemistry P3 7/6/2010  (Read 21077 times)

Offline Ivo

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Re: Chemistry P3 7/6/2010
« Reply #15 on: June 01, 2010, 02:47:20 pm »
how do you know what the isomers are named?

It's complicated.  We shall use the isomers of butane as the example.  The first one is easy, just butane.  The second one:

a) You take the longest carbon cahin and name the compound after the number of carbon atoms in the longest chain.  In this case, there are three carbon atoms in the longest chain.  So it is named after propane.

b) You then look for the alkyl side chain.  In this case it is a methyl group (CH3).  So the compound is methylpropane.

c) You then have to number the alkyl group side chain by counting the numbers of the carbon atoms from one end of the carbon chain.  You count from the end of the carbon chain that gives you the lowest number.  In this case counting from the left/right, the alkyl group is on the second carbon atom.  So the compound is 2-methylpropane.
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Offline jellybeans

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Re: Chemistry P3 7/6/2010
« Reply #16 on: June 01, 2010, 02:50:02 pm »
It's complicated.  We shall use the isomers of butane as the example.  The first one is easy, just butane.  The second one:

a) You take the longest carbon cahin and name the compound after the number of carbon atoms in the longest chain.  In this case, there are three carbon atoms in the longest chain.  So it is named after propane.

b) You then look for the alkyl side chain.  In this case it is a methyl group (CH3).  So the compound is methylpropane.

c) You then have to number the alkyl group side chain by counting the numbers of the carbon atoms from one end of the carbon chain.  You count from the end of the carbon chain that gives you the lowest number.  In this case counting from the left/right, the alkyl group is on the second carbon atom.  So the compound is 2-methylpropane.

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Offline J.Darren

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Re: Chemistry P3 7/6/2010
« Reply #17 on: June 01, 2010, 03:37:26 pm »
Properties of Alcohols :

-OH (Hydroxyl) functional group
General formula : Cn H(2n+1) OH

Ethanol can be manufactured :

- Hydration of ethene
- Fermentation

Ethanol burns with a clean flame. It is used for camping stoves or as a fuel for cars.

The complete combustion of etanol produces carbon dioxide and water.

Ethanol is also used as a fuel, as a solvent in perfume, alcoholic drinks and making esters.
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Offline J.Darren

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Re: Chemistry P3 7/6/2010
« Reply #18 on: June 01, 2010, 03:43:46 pm »
Properties of Organic Acids :

-COOH functional group
General formula : Cn H(2n+1) COOH

Ethanol is oxidised to ethanoic acid.

Ethanol + O2 (from the air) -> Ethanoic acid + Water

When ethanol is heated with acidified K2Cr2O7 (Potassium dichromate), ethanoic acid is formed.

Ethanol + O2 (from the oxidising agent) -> Ethanoic acid + Water

Organic acids are weak acids, they are partially ionised in aqueous solution. They all have the typical acid properties.

Metal + Acid -> Salt + Hydrogen

Magnesium + Ethanoic acid -> Magnesium ethnoate [(Ch3COO)2Mg] + Hydrogen

Base + Acid -> Salt + Water

Magnesium + Ethanoic acid -> Magnesium ethnoate [(Ch3COO)2Mg] + Water

Carbonate + Acid -> Salt + Carbon Dioxide + Water

Sodium Carbonate + Ethanoic acid -> Sodium ethnoate [(Ch3COO)Na] + Carbon Dioxide + Water
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Offline J.Darren

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Re: Chemistry P3 7/6/2010
« Reply #19 on: June 01, 2010, 04:05:16 pm »
Properties of Esters :

Ethanoic acid + Ethanol -> Ethyl Ethnoate + QWater

Condition :

- Heat
- Concenterated sulphuric acid as catalyst

Esters are used in food flavourings.

When writing the name of an ester, the group from the alcohol comes before the part from the part from the acid. For example if methanol is reacted with propanoic acid, we will get methyl propanoate.

When drawing an ester, the acid part is on the left and the alcohol part is on the right.
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Offline Ivo

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Re: Chemistry P3 7/6/2010
« Reply #20 on: June 01, 2010, 04:12:58 pm »
Properties of Esters :

Ethanoic acid + Ethanol -> Ethyl Ethnoate + QWater

Condition :

- Heat
- Concenterated sulphuric acid as catalyst

Esters are used in food flavourings.

When writing the name of an ester, the group from the alcohol comes before the part from the part from the acid. For example if methanol is reacted with propanoic acid, we will get methyl propanoate.

When drawing an ester, the acid part is on the left and the alcohol part is on the right.

I've included pictures so it's more obvious for people to see! :P
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Offline J.Darren

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Re: Chemistry P3 7/6/2010
« Reply #21 on: June 01, 2010, 04:16:21 pm »
I've included pictures so it's more obvious for people to see! :P
Thanks Ivo.

Kimo : I am planning to do Air and water, Carbonates and Sulphates, perhaps you might be willing to help out with the remainder of the topics ???
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Offline contraentry

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Re: Chemistry P3 7/6/2010
« Reply #22 on: June 01, 2010, 04:26:27 pm »
WOW! Thank you guys Soooooooo MUCH!! These are so helpful!

Offline guMnam

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Re: Chemistry P3 7/6/2010
« Reply #23 on: June 01, 2010, 11:13:32 pm »
Thanks

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Offline haris94

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Re: Chemistry P3 7/6/2010
« Reply #24 on: June 02, 2010, 08:10:33 am »
good job dude
amazing notes
keep going
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Offline rameeziiii

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Re: Chemistry P3 7/6/2010
« Reply #25 on: June 02, 2010, 01:13:13 pm »
did you get this from the study guide?... anyway thanks

Offline J.Darren

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Re: Chemistry P3 7/6/2010
« Reply #26 on: June 02, 2010, 03:04:14 pm »
did you get this from the study guide?... anyway thanks
Yeah, but I filtered out the information that are not essential.
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Offline NidZ- Hero

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Re: Chemistry P3 7/6/2010
« Reply #27 on: June 02, 2010, 03:40:08 pm »
Yeah, but I filtered out the information that are not essential.
i wanna help temme which topic do u want me 2 do :)

Offline J.Darren

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Re: Chemistry P3 7/6/2010
« Reply #28 on: June 02, 2010, 03:45:45 pm »
i wanna help temme which topic do u want me 2 do :)
I shall be responsible for the remainder of Organic Chemistry, Air and Water, Carbonates and Sulphates.
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Offline Ivo

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Re: Chemistry P3 7/6/2010
« Reply #29 on: June 02, 2010, 03:48:12 pm »
Yeah, but I filtered out the information that are not essential.

By the way, which study guide is this from, may I ask?
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