Homework Help Forum: 10th grade

Posted by anonymous on Sunday, August 16, 2009 at 4:14pm.

i neeed help determining whether the following changes are chemical or physical and why. i have some guesses but i wanted to have them verified. thanks. =) 1) mixing chalk and vinegar: chem. b/c it bubbles 2) mixing starch and iodine: physical b/c the iodine dissoles and the satrch falls to the bottom of the beaker, (but the mixture turns purple) 3) ammonia abd iron (III) chloride: physical b/c the mixture eventually settles out,(but there is a color change.) please help me to verify. thanks

• 10th grade - drwls, Sunday, August 16, 2009 at 4:41pm

  1) correct 2) read http://en.wikipedia.org/wiki/Iodine_test and guess again 3) wrong. The color change is a clear indication of a chemical reaction.

  
  

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