Learning how to infer the reactions are whether chemical changes or physical changes. And record some recongnizable characteristics of chemical changes.
Materials and Equipments:
Refer to page 18 in Health Lab Text , Lab 2C
Equipments:
4 small test tubes 10mmX75mm
test tube rack
4 medicine dropper
glass square
lab apron
safety goggles
four unknown chemical reagents(one is green, the others are all transparent)
procedure:
Refer to Page 18 in Health Lab Text, Lab 2C
Data and Observation:
Analysis of Results
B+A Chemical Change
C+A Physical Change
D+A Chemical Change
C+B Chemical Change
D+B Chemical Change
D+C Physical Change
Following-Up Questions:
a)Chemical change: Burn some papers, cook meat
b)Physical change: tear some papers, ice melt
Sources of Error:
There are some drops of liquid in the glass square.
That could be water or other solutions which might affect the results.
Conclusion:
According to the results of this lab, we conclude that chemical changes happen with new substances formed and physical changes take place with new substances formed.
Not like chemical changes, physical changes are reversable.
In this lab, chemical changes happen in the form of color changing, air bubbles and sediments generation.
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