Latest Diablo 3 News
DiabloWiki Updates
Support the site! Become a Diablo: IncGamers PAL - Remove ads and more!

Chem help please

Discussion in 'Off-Topic' started by zodiac66, Sep 6, 2006.

  1. zodiac66

    zodiac66 IncGamers Member

    Joined:
    Jun 22, 2003
    Messages:
    4,966
    Likes Received:
    18
    Trophy Points:
    467
    Chem help please

    So far I have understood everything except condensation reactions and hydrolysis. I have been looking on the net and I can't find anything in simple terms.

    If anyone would be willing to lend a hand with ideas that I don't understand, I would appreciate it. I am getting a tutor tomorrow (at least signing up for one) but I need to know this stuff for Friday.
     
  2. superdave

    superdave IncGamers Member

    Joined:
    Mar 14, 2004
    Messages:
    12,402
    Likes Received:
    64
    Trophy Points:
    472
    isn't hydrolysis just the opposite of condensation? hydrolysis occurs when a molecule gets divided into two by reacting with a molecule of water...the one part gets OH and the other part an H....condensation occurs when two molecular parts join together for each molecule of h2o produced....meh...it's been too long since i had a chemistry book open to a page that didn't tell me how to make big explosions.
     
  3. Dondrei

    Dondrei IncGamers Member

    Joined:
    Aug 1, 2005
    Messages:
    36,855
    Likes Received:
    30
    Trophy Points:
    467
    Sorry, I've forgotten all my Chemistry too...
     
  4. Module88

    Module88 IncGamers Member

    Joined:
    Jun 27, 2003
    Messages:
    5,722
    Likes Received:
    6
    Trophy Points:
    466
    You just need help defining terms? Or is it the reactions themselves?
     
  5. zodiac66

    zodiac66 IncGamers Member

    Joined:
    Jun 22, 2003
    Messages:
    4,966
    Likes Received:
    18
    Trophy Points:
    467
    The reactions. I can understand the definition, but when looking at the molecules and how they react I am lost. My student advisor said that I wouldn't need to know that for the test, but I will at some point so I may as well learn it now.

    I also start to get a little iffy about polar molecules and solubility. As before, I understand the definition but not the concept.
     
  6. Omikron8

    Omikron8 IncGamers Member

    Joined:
    Jun 28, 2003
    Messages:
    8,171
    Likes Received:
    0
    Trophy Points:
    165
    hydrolysis is as stated a reaction with water resulting in the rupture of some important bond in the starting molecule

    condensation is when two or more molecules react together to form one molecule accompanied by the expulsion of another small product, usually water

    as you can tell i suck at definitions
     
  7. The Future now

    The Future now Banned

    Joined:
    Mar 27, 2006
    Messages:
    492
    Likes Received:
    0
    Trophy Points:
    0
    Polar Molecules: Here's how I do it. First, draw the lewis structure. 2nd, recall that electronegativity increases as you move across and up the periodic table. Now, I usually just imagine the extremely electronegative atoms as being "heavier" than the not so electronegative atoms. Now that you have that in your head, imagine placing the molecule on a flat surface. If it leans to one side, its polar. If its more or less balanced, its not.

    As far as solubility, "like dissolves like" is a good rule to go by. Umm . . . alcohols dissolve in water due to H bonding, (present on the hydroxide) so the solubility is relative to the molecular weight.
     
  8. superdave

    superdave IncGamers Member

    Joined:
    Mar 14, 2004
    Messages:
    12,402
    Likes Received:
    64
    Trophy Points:
    472
    if you look at the molecules you should be able to tell if a water molecule is added(hydrolysis) or lost(condensation)....think of a couple of molecules smacking into each other...there will be some exchange of atoms and bonds.
     
  9. zodiac66

    zodiac66 IncGamers Member

    Joined:
    Jun 22, 2003
    Messages:
    4,966
    Likes Received:
    18
    Trophy Points:
    467
    Ok..so, can you give me an example of each with everyday, for lack of a better word, ingredients? Such as..sugar and water...oil and water.
     
  10. RevenantsKnight

    RevenantsKnight IncGamers Member

    Joined:
    Oct 4, 2004
    Messages:
    1,334
    Likes Received:
    0
    Trophy Points:
    120
    This help any?

    In terms of figuring out where the bonds will be forming/breaking, I find it's easiest to start with the products and work back from there. Apologies if you're already doing that.
     
  11. superdave

    superdave IncGamers Member

    Joined:
    Mar 14, 2004
    Messages:
    12,402
    Likes Received:
    64
    Trophy Points:
    472
    a picture says a thousand words.
     
  12. zodiac66

    zodiac66 IncGamers Member

    Joined:
    Jun 22, 2003
    Messages:
    4,966
    Likes Received:
    18
    Trophy Points:
    467
    This is a challange..and I like it. I have been told not to worry about the chem just learn the definition. I can't do that.

    I think I will also visit the prof during office hours. It certainly couldn't hurt. I am not one to regurgitate facts without understanding the concept behind it. I was looking around the class today and I was the only one who had the printed study guides. That was highly advised by the profs. I had mine all scattered around the desk. I was referring back to other concepts to understand the new ones. I think he noticed. Everytime I looked up..he was looking at me...and I usually look pretty ratty that time of morning so it wasn't my looks. Maybe he thought I was amusing in my disorganization or maybe he thought I was someone that was determined to learn. That class just flies by.

    I forgot to mention that I am a kinesthetic learner.
     
  13. Rius666

    Rius666 IncGamers Member

    Joined:
    Nov 19, 2003
    Messages:
    1,614
    Likes Received:
    0
    Trophy Points:
    165
    Try getting a set of chem models...you know, those little balls and sticks. If you can't learn from pictures or words maybe you will be able to learn visually and, as you said, kinesthetically. Being able to see the bonds and the break/forming of bonds due to the polar nature of water really helps.

    For me understanding polarity was easy once I understood and applied the concept of electronegativity. Certain elements will attract/hold onto their electrons more than other elements and certain elements will like to donate their electrons. Oxygen is a fairly electronegative (meaning it likes electrons) element because of the 2 half-empty shells in its p-orbital (don't worry about that just know it's electronegative). Hydrogen is less electronegative than oxygen so when 2 hydrogens bond to oxygen there's a dipole effect, causing a polarity (you'll learn this in inorganic chem):

    H-O-H (the H's are near the top of the O, imagine an outline of mickey mouse's face and the ears are H and the head is O). So because oxygen is more electronegative, it will pull the electrons from the H's closer to its orbital, essentially giving them a small + charge and oxygen and small - charge.

    +H--====O===--H+
    This is the best illustration I can come up with. The closer you get to the nucleus of the O the more negative it will be.
     
  14. Moosashi

    Moosashi IncGamers Member

    Joined:
    Jul 19, 2003
    Messages:
    2,711
    Likes Received:
    1
    Trophy Points:
    120
    Don't you have a TA? I bet no one goes to your poor TA's office hours, yet he or she is there, waiting and hoping for you to come with your chemistry questions. :wave:
     
  15. Module88

    Module88 IncGamers Member

    Joined:
    Jun 27, 2003
    Messages:
    5,722
    Likes Received:
    6
    Trophy Points:
    466
    I'm a little fuzzy, so bear with me Zod.

    There are two things required for a compound to be polar.

    1. Polar bonds (due to electronegativity)
    2. Assymetry.

    Also, IIRC, a lone pair must be present on the central atom. This is necessary, but not sufficient. What we also need to look at is what Rius said above. Will atoms tend to be pulled toward a particular end because of the electronegativity difference? If it is, and satisfies all of the conditions, it's a polar molecule.

    As far as solubility is concerned, there are a host of rules that I'm not too particularly interested in explaining. Is there a specific thing you have a question about as far as solubility is concerned?
     
  16. buttershug

    buttershug IncGamers Member

    Joined:
    Feb 13, 2005
    Messages:
    8,207
    Likes Received:
    5
    Trophy Points:
    255

    I had a chem prof who said if you learn nothing else from this class, learn this, "like disolves like"

    Which is why water is the unersal solvent because it is both polar and has hydrogen bonding.
     
  17. Omikron8

    Omikron8 IncGamers Member

    Joined:
    Jun 28, 2003
    Messages:
    8,171
    Likes Received:
    0
    Trophy Points:
    165
    no, we actually don't want anyone to come with questions (yes i'm a chem TA)

    in fact we are obligated to not see students outside the labs that we supervise
     
  18. Sir EvilFreeSmeg

    Sir EvilFreeSmeg Banned

    Joined:
    Aug 30, 2005
    Messages:
    15,434
    Likes Received:
    3
    Trophy Points:
    0
    Chemistry I need to know:

    Soda + Mentos = fun
    Men + women = fun
    Booze + living = fun
    Booze + the fuzz = no fun
     

Share This Page