Author Topic: Chemistry P3 7/6/2010  (Read 24452 times)

Offline Ivo

  • SF Geek
  • ****
  • Posts: 515
  • Reputation: 2767
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.
Always willing to help!  8)
"In helping others, we shall help ourselves, for whatever good we give out completes the circle and comes back to us."

Offline jellybeans

  • ,i'm hungry xB
  • SF Senior Citizen
  • *****
  • Posts: 826
  • Reputation: 837
  • Gender: Female
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.

THANK YOU ! :D
You said I must eat so many lemons cause I am so bitter.

Offline J.Darren

  • SF Geek
  • ****
  • Posts: 405
  • Reputation: 956
  • Gender: Male
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.
Do not go where the path may lead. Go instead where there is no path and leave a trail.

Offline J.Darren

  • SF Geek
  • ****
  • Posts: 405
  • Reputation: 956
  • Gender: Male
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
Do not go where the path may lead. Go instead where there is no path and leave a trail.

Offline J.Darren

  • SF Geek
  • ****
  • Posts: 405
  • Reputation: 956
  • Gender: Male
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.
Do not go where the path may lead. Go instead where there is no path and leave a trail.

Offline Ivo

  • SF Geek
  • ****
  • Posts: 515
  • Reputation: 2767
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
Always willing to help!  8)
"In helping others, we shall help ourselves, for whatever good we give out completes the circle and comes back to us."

Offline J.Darren

  • SF Geek
  • ****
  • Posts: 405
  • Reputation: 956
  • Gender: Male
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 ???
Do not go where the path may lead. Go instead where there is no path and leave a trail.

Offline contraentry

  • SF Citizen
  • ***
  • Posts: 177
  • Reputation: 1303
  • Gender: Male
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

  • !!~~**~~!!
  • SF Farseer
  • *******
  • Posts: 4242
  • Reputation: 12471
  • Gender: Male
  • !!~~guMnam~~!!
Re: Chemistry P3 7/6/2010
« Reply #23 on: June 01, 2010, 11:13:32 pm »
Thanks

I <3 Challenges
Never give up :)

Offline haris94

  • SF Senior Citizen
  • *****
  • Posts: 930
  • Reputation: 984
  • Gender: Male
Re: Chemistry P3 7/6/2010
« Reply #24 on: June 02, 2010, 08:10:33 am »
good job dude
amazing notes
keep going
WHAT WE DO IN LIFE ECHOES AN ETERNITY

Offline rameeziiii

  • I haz big water spear... make good BBQ
  • SF Geek
  • ****
  • Posts: 432
  • Reputation: 59609
  • Gender: Male
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

  • SF Geek
  • ****
  • Posts: 405
  • Reputation: 956
  • Gender: Male
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.
Do not go where the path may lead. Go instead where there is no path and leave a trail.

Offline NidZ- Hero

  • People say i m borderline crazy Sorta kinda :D
  • SF Senior Citizen
  • *****
  • Posts: 958
  • Reputation: 21263
  • Gender: Female
  • IDK what makes u such a LOSER.But it really works
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

  • SF Geek
  • ****
  • Posts: 405
  • Reputation: 956
  • Gender: Male
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.
Do not go where the path may lead. Go instead where there is no path and leave a trail.

Offline Ivo

  • SF Geek
  • ****
  • Posts: 515
  • Reputation: 2767
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?
Always willing to help!  8)
"In helping others, we shall help ourselves, for whatever good we give out completes the circle and comes back to us."