How do u differente between physical and chemical properties PLEASE READ!!!

Subject: How do u differente between physical and chemical properties PLEASE READ!!!

Date: Fri Apr 21 16:15:35 2000
Posted by Kim
Grade level: 10-12 School: No school entered.
City: No city entered. State/Province: No state entered. Country: No country entered.
Area of science: Chemistry
ID: 956351735.Ch

Message:


Hello again, 
Is this right???

Physical Properties of Caffeine:

Qualitative Physical Properties:
· pure caffeine is a white, odorless powder
· crystallizes into long, white needlelike crystals
· the crystals loose their water of hydration slowly to give a white solid
· neutral to litmus paper
· bitter taste

Quantitative Physical Properties:
· molecular weight is 194.19g
· melting point is 238 C (460 F)
· point at which caffeine sublimes is 178 C (352 F) at atmospheric pressure
· pH is 6.9

Chemical Properties of Caffeine
· generally non-reactive
· soluble in hot water
· upon cooling, the solution deposits crystals of caffeine monohydrate

Are they in the right spot, I'm having trouble differentiating between 
physical and chemical properties.  Please respond, thanks a lot!!!

~Kim

Re: How do u differente between physical and chemical properties PLEASE READ!!!

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