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Author Topic: CHEM AND BIO HELP AND TIPS HERE  (Read 357900 times)

Offline Raywin

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1845 on: May 24, 2010, 11:59:55 am »
Quote from: jellybeans on May 24, 2010, 11:55:53 am
wait... so diluting an acid decreases the pH? :/ or does it only apply to how "strong" and "weak" the acid is?

Diluting an acid INCREASES the pH, meaning makes it more basic. This is because its concentration decreases and so it becomes a weaker acid and so its ph changes.. hope u got me.. :P 
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Offline jellybeans

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1846 on: May 24, 2010, 12:01:09 pm »
Quote from: Raywin on May 24, 2010, 11:59:55 am
Diluting an acid INCREASES the pH, meaning makes it more basic. This is because its concentration decreases and so it becomes a weaker acid and so its ph changes.. hope u got me.. :P 

hahaha, ohhh okayy. lol i always thought the pH was only related to how many H+ ions are dissociated, :P XD teheeee; anyways, thanks ;D
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Offline Raywin

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1847 on: May 24, 2010, 12:02:03 pm »
Quote from: jellybeans on May 24, 2010, 12:01:09 pm
hahaha, ohhh okayy. lol i always thought the pH was only related to how many H+ ions are dissociated, :P XD teheeee; anyways, thanks ;D

Lol..  ;D no problem... :)
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Offline luv3life

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1848 on: May 24, 2010, 12:12:47 pm »
Guys, I'm stressed for Chem P1. Any quick notes? :) Oh and here's an MCQ question:

How are you studying for Chemistry P1?
A. Learning the text book (lol, crazy!)
B. Reading your class notes (takes ages!)
C. Solving question papers (pain in the A**!)
D. Just SFing (fun!)

My take is obviously option D. :P
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Offline jellybeans

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1849 on: May 24, 2010, 12:19:46 pm »
queeeeestion.

O/N 03 Chem P1 ; Q9 !

The diagrams show the bonding in three covalent molecules.
1) O-O
2) O-O < DOUBLE BOND
3) O-O < TRIPLE BOND

WHich of these molecules combine to form ammonia?

A) 1 and 2
B) 1 and 3
C) 2 and 3
D) 1,2 and 3

..explanation? D:
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Offline Raywin

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1850 on: May 24, 2010, 12:28:38 pm »
Quote from: jellybeans on May 24, 2010, 12:19:46 pm
queeeeestion.

O/N 03 Chem P1 ; Q9 !

The diagrams show the bonding in three covalent molecules.
1) O-O
2) O-O < DOUBLE BOND
3) O-O < TRIPLE BOND

WHich of these molecules combine to form ammonia?

A) 1 and 2
B) 1 and 3
C) 2 and 3
D) 1,2 and 3

..explanation? D:

Its easy.. see ammonia is NH3 and before N and H react, N exists as N---N(triple bond) AND H exists as H-H(single bond) so its 1 and 3!!! :P
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Offline jellybeans

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1851 on: May 24, 2010, 12:30:21 pm »
Quote from: Raywin on May 24, 2010, 12:28:38 pm
Its easy.. see ammonia is NH3 and before N and H react, N exists as N---N(triple bond) AND H exists as H-H(single bond) so its 1 and 3!!! :P

.... why's Nitrogen triple bonded? >P<
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Offline Raywin

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1852 on: May 24, 2010, 12:32:14 pm »
Quote from: jellybeans on May 24, 2010, 12:30:21 pm
.... why's Nitrogen triple bonded? >P<

Cause its found like tht right? N2 is N---N as each N atom has 5 outer-most electrons... so in a molecule its a triple bond... :)
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Offline jellybeans

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1853 on: May 24, 2010, 12:33:52 pm »
Quote from: Raywin on May 24, 2010, 12:32:14 pm
Cause its found like tht right? N2 is N---N as each N atom has 5 outer-most electrons... so in a molecule its a triple bond... :)

OH RIGHTTTTT, LOL it has to take.. 3 more electrons , so its triple bonded? :B hahahaha. OKAY, thanks ;D
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Offline Raywin

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1854 on: May 24, 2010, 12:34:34 pm »
Quote from: jellybeans on May 24, 2010, 12:33:52 pm
OH RIGHTTTTT, LOL it has to take.. 3 more electrons , so its triple bonded? :B hahahaha. OKAY, thanks ;D

Hahaha.. yeah thts it.. :) np.. :D
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Offline luv3life

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1855 on: May 24, 2010, 12:34:48 pm »
jellybeans: Nitrogen atom has 5 electrons in outermost orbit. In order to achieve noble gas status, it requires 3 more electrons. These 3 will come from where? Covalent bonds with other Nitrogen atoms. Thus, Nitrogen is triple-bonded. :)

Am I right, guys? Just gave it a try.
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Offline luv3life

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1856 on: May 24, 2010, 12:35:50 pm »
Awwwh mayn! I type tooo slow. Someone else already gave jellybeans an answer.  :-\
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Offline jellybeans

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1857 on: May 24, 2010, 12:37:30 pm »
Quote from: luv3life on May 24, 2010, 12:35:50 pm
Awwwh mayn! I type tooo slow. Someone else already gave jellybeans an answer.  :-\

hahahahaha, like the way you say my name. XD LOL, thanks anyways, :D
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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1858 on: May 24, 2010, 01:13:06 pm »
Can ethene be cracked ?
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Offline jellybeans

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #1859 on: May 24, 2010, 01:17:09 pm »
O/N 2003 CHEM P1 , Q36!
Which compound is unsaturated and forms a neutral solution in water?

A) CH2OH-CH--CH-CH2OH
B) CH2OH-CH2-CH2-CH2OH
C) CO2H-CH--CH-CO2H
D) CO2H-CH2-CH2-CO2H

i get the unsaturated bit.. but how do you know if it's neutral or not?
doesnt the 'OH' group make it ... acidic? :B hehs, explanation neeeeeded svp, (X
 :P
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