Ciencia

Physical and Chemical Changes
Physical and Chemical Changes



Christian Alvarez Gerardo Valdés Andrés Díaz S.9-3 Sept. 23, 2011


Christian Alvarez Gerardo ValdésAndrés Díaz S. 9-3 Sept. 23, 2011


Summary
In this practice the difference between chemical and physicalchanges were observed in different ways. The first chemical reaction experienced during the series of experiments was burning a candle. Later there were chemical reactions between: paper and fire, NaCl andAgNO3, HCl and Mg and finally between vinegar and baking soda. These were all chemical changes because there were chemical reactions that produced a new substance. Some chemical changes that could beobserved were heat, light and bubble production, the formation of new substances for example ashes and gas.
The first physical reaction observed was wax melting producing a physical change. Laterthere were physical reactions like: breaking wax, melting candle wax, tearing paper, dissolving NaCl (salt), tearing Mg ribbon, grinding and heating CuSO4-5H2O and adding water to CuSO4.These were allphysical changes because none of its properties were change.
Hypothesis
If a new substance is formed then a chemical reaction has taken place and not a physical change.
Data
Table 1: Chemical andPhysical changes

Reaction | P or C? | Your Observations | New substance formed |
Scraping wax with spatula | P | We are breaking it into pieces. | NO |
Melting Candle Wax | P | The wax becameliquid. | NO |
Burning a Candle | C | There is heat and light production. | ASHES |
Tearing Paper | P | The paper was turned into little pieces. | NO |
Burning Paper | C | The paper was turned...