Endothermic and Exothermic Reactions

November 13, 2008 Endothermic and Exothermic Reactions Day 1, Prd 4

Purpose: To investigate heal transfer in reaction

***Please refer to the hand-out given before the lab for the procedure and the materials used.








　
　
　
　
　

Observations:

Reaction 1:

When calcium chloride and phenolphthalein touched the water and when they were shook together, they were bubbles forming and along with them was a fizzing sound. Also, as the ziploc bag was shook and as the time passed, the bag felt hot and there was this smell. It smelled like burning plastic to me. Furthermore, as minutes passed, the calcium chloride and phenolphthalein mixture caught a pink tink and eventually, the contents of the ziploc bag turned pink.

Reaction 2:

There was a fizzing sound, big bubbles - bigger than the bubbles in the first reaction. The ziploc bag felt cold and its contents turned whitish when the bubbles were forming and turned cloudy when the bubbles from the reaction disappeared. The ziploc bag was also inflating as the bubbles were forming.

The burning splint lost its light when inserted in the bag. Our hypothesis is that the gas created was carbon dioxide because CO2 turns the flames off.

Reaction 3:

There were bubbles, and a fizzing sound. The reacton was odorless but it had colour. After the reaction, some bubbles stayed on the surface of the Ziploc bag. The liquid in the Ziploc bag was white and as the reaction passed, the colour of the liquid went from white to transparent.

Conclusion:

I learned that bubbles can affect the colour of the liquid. Also, water, when added to compunds, form bubbles.