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Are you confused about the difference between chemical changes and physical changes and how to tell them apart? In a nutshell, a chemical change produces a new substance, while a physical change does not. A material may change shapes or forms while undergoing a physical change, but no chemical reactions occur and no new compounds are produced.

Examples of Chemical Changes

  • burning wood
  • dissolving salt in water
  • mixing acid and base
  • digesting food

Examples of Physical Changes

  • crumpling a sheet of paper
  • melting an ice cube
  • casting silver in a mold
  • breaking a bottle

How to Tell?

Look for an indication that a chemical change occurred. Chemical reactions release or absorb heat or other energy or may produce a gas, odor, color or sound. If you don't see any of these indications, a physical change likely occurred.

In some cases, it may be hard to tell whether a chemical or physical change occurred. For example, when you dissolve sugar in water, a physical change occurs. The form of the sugar changes, but it remains the same chemically (sucrose molecules). However, when you dissolve salt in water the salt dissociates into its ions (from NaCl into Na+ and Cl-) so a chemical change occurs. In both cases a white solid dissolves into a clear liquid and in both cases you can recover the starting material by removing the water, yet the processes are not the same.

Comments

November 8, 2011 at 5:27 am
(1) ziana says:

it elps piple

August 15, 2012 at 5:42 am
(2) Renee31 says:

So short of the examples wish there is more :) )

September 26, 2012 at 9:24 pm
(3) destiny perkins says:

please show me more

September 28, 2012 at 11:16 am
(4) Annonymous says:

Learn to spell ur comments

October 12, 2012 at 9:47 am
(5) Squareshawty says:

Using salt water at and example for Physical Changes are great!

November 6, 2012 at 11:03 pm
(6) kiara says:

Thanks soo much :) but wish there was more examples

December 5, 2012 at 2:47 pm
(7) dru says:

thanks wish there was abut proporties

June 7, 2013 at 6:16 am
(8) candy says:

tanks for the help but i waish there were more

June 18, 2013 at 11:38 am
(9) rajvi says:

thaxs should have given more examples!

October 8, 2013 at 8:41 pm
(10) Mackenzie says:

Helpful!!!! There just needs to be more examples of chemical changes

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