Sunday, October 16, 2011

Chemical Change vs. Physical Change: Can YOU Spot the Difference?


We began learning about chemical and physical changes in class. We learnt that a chemical change occurs when when a new substance is made, & old bonds are broken while new ones are made. An example of a chemical change would be cooking an egg On the contrary, physical changes DO NOT produce a new substance. An example would be ice melting --> the ice melts into water however the same substance is present, there's just a change in state.





The diagram below shows the changes in state when they undergo any physical changes :


In order to spot the difference between the two, we took many things into consideration:
  • colour change
  • change in state
  • odour
  • light
  • heat
Another simple way to tell if a chemical or physical change has occurred is by looking at its chemical equation. Let's say, for example, an ice cube melted and I was trying to detect which change it had gone through, but I was still unsure even after I did an expirament. I would look at it's chemical equation:

Ex. H2O (s)à H2O (l)

I noticed that the reactant was the same as the product, the only difference is the change in state from a solid (s) to a liguid (l).


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