Chemistry :)

[Dynamite]

Hey guys, so I had some questions that my Chemistry teacher set for us. (28 to be specific :P ) and I didn't understand 2 of them.
Maybe someone could help?

Cheers:

Suggest why it may be an advantage to leave dirty clothing to soak for a while in a solution of washing powder containing enzymes before beginning the wash cycle of the washing machine.
( some pointers please? )

Why is it important that the solvents used in dry-cleaning evaporate quickly?

I am awful at chemistry, so help is really appreciated :)

Thanks again.

[Shuttleu]

enzymes breakup stuff into smaller stuff such as proteins

if you leave something to soak in enzymes then they will break the dirt up so it is easier to clean

for the second one, i have absolutely no idea

~shut

[Dynamite]

Thank you very much shuttle :)

[Shuttleu]

no problem

if you want to know about enzymes i would suggest looking for the lock and key model

~shut

EDIT: http://en.wikipedia.org/wiki/Enzyme#.22Lock_and_key.22_model
the lock and key model will help you understand what they do

[Dynamite]

ok, will do that.
Thanks again

[pyroryan]

I don't really know how dry-cleaning works but I'll take a guess at it. Solvents dissolve the dye in the cloths and so if they don't dry quickly, the color will transfer onto other parts/cloths.

[Cstrike]

To add on to Shuttleu's point, if you have some large protein, it's going to be insoluble and stick around. If you break it into many small amino acids, compounds like water can dissolve them much more easily and remove them. Hydrogen bonding is key, for example if an enzyme breaks a disulfide bond between the amino acid (Cysteine ---- Cysteine), they will go from S-S disulfide bonds to S-H (x2) thiol bonds (thiol means a sulfur bonded to a hydrogen); my logic would be that this creates more possible hydrogen bonding sites, thus allowing to be easily dissolved. Plus upon breaking up you get a carboxylic acid and an amino group, those should be water soluble (though COOH's are really weird at times, I had one once that would just NOT dissolve).

Though I feel like I'm not actually hitting the point of the question, and feel like I'm babbling on again ;)

hopefully that helps-- if you need more help, myself + others will continue to assist!

[i luffs yeww]

:p Pretty simple stuff was missed here, too.

Soap works because it has both a polar end and a non-polar end. The polar end attaches to the water and the non-polar end attaches to the stain/whatever. This causes water's cohesion and adhesion properties to not work as well. Pretty basic chemistry that should sum it up..

And enzymes in laundry detergent/whatever are usually only to break down proteins. I have notes on this somewhere, but I really don't care that much right now.

The dry-cleaning one.. Uh.. a few things that may contribute.

When enzymes heat up, they become denatured. This causes them to not be able to function correctly, which then leads to them to stop cleaning (stops discoloring maybe?).

More heat contributes to more uhh.. can't remember. :p Sorry. But anyway, more heat leads to more activity, more reactions, etc. Could do more than it's supposed to if it heats too slow, because it would "eat" through the colors/clothing.

Sorry, I'm somewhere around cloud nine right now. I can send you some notes from my IB HL Bio textbook if you want? Might help.

Good luck.