Racism

Only available on StudyMode
  • Download(s) : 95
  • Published : April 23, 2013
Open Document
Text Preview
Majuma Mganga
period 7
Chemistry
Rubber Bands and Spontaneity

Purpose: The purpose of this activity was to determine if a chemical or a physical change is spontaneous. This activity was also designed to determine if a change is spontaneous by using change in enthalpy and change in entropy with the structure of polymers.

Hypothesis: If you heat the rubber band and then streatch it, then the rubber band will become shorter meaning it will release eneregy because it is not relaxed and the polymers are disordered.

Observations: During the avtivity we observed many things. Due to this experiment i have observed many things such as the fact that when we heated up the rubber band, it became shorter. Also when we streatched the subber band was wormer and when we relaxed it the rubber band was cooler because it was more relaxed and orginized. All in all, we observed that when the particles were disorganized the entropy had increased.

Data:
Hair driar- Endothermic( Heat) positive
Ice cubes- Exothermic( taking heat away)
Enthalpy- Endothermic( positive)
Entropy- Exothermic( negative)

Changes:
When the rubber band became shorter ( Endothermic)
When the rubber band became longer( Exothermic)

Tendencies In Spontaneity:
Dalta H is negative
Dalta S is postive
Gibbs free energy- Dalta G= Dalta H - T Dalta S
Dalta G is postitve > Not Sponteneous
Dalta G is negative > Sponteneous

Conclusion:
This activity was very intresting and helpful and educating in learing about polymers and how to determine spontaneity using different materials. When heat energy is released from the system, the surroundings gain that energy, while the system losses energy. The far more important lesson of this activity was to realize that the two factors that affect spontaneity are changes in enthalpy and changes in entropy. My hypothesis was correct because during the investigation If you heat the rubber band and then streatch it, then the rubber band...
tracking img