Chemistry in a bag review

I worked with Emilie on this "chemistry in a bag" project. We had four ingredients: calcium chloride, sodium bicarbonate, phenol red, and water. The calcium chloride was white, beady, hard, and didn't have a smell. Sodium bicarbonate-which is better known as baking soda- was white, powdery, semi-chunky, and didn't have a smell either. The phenol red was red (of course), a liquid, and smelled horrible. Be careful, it can stain clothing. The water was... well water. We were assigned to take 1 scoop of each solid and 1 pipet of each liquid and put them all in a bag, keeping the liquid and solids separate until we closed the bag. Then I shook the bag while Emilie recorded the observations. The phenol red and water mixed together and created a pink color. The bag temperature went from room temperature to hot to cold while I was shaking the bag. Our bag started to fill up with gas, but it wasn't on the verge of exploding like some other people's bags were. Emilie and I were supposed to figure out what caused what, so we tested separate ingredients together.





We tested sodium bicarbonate, calcium chloride, and water together. This combo created a lot of gas, but didn't create anything else. We decided that baking soda, calcium chloride, and water created gas. Next, we tested sodium bicarbonate and phenol red. When mixed, it created a magenta color, it was cold, and it didn't have a smell. Then we tested the calcium chloride and phenol red. It was the same magenta shade and the sodium bicaronate and the phenol red but started as a yellow color. It was hot, and when wafted, it smelled horrible, like rubbing alcohol. We concluded that the phenol red was causing the smell and color. We decided to test for the temperatures. So we tested water and calcium chloride. This created heat, concluding that calcium chloride was in charge of it. We then tested for cold, while we were on the temperature questioning. We mixed phenol red, sodium bicarbonate, and water. It turned magenta again and created the coldness we were looking for. Therefore, sodium bicarbonate, when mixed with liquid, created coldness.





So, just to sum everything up:





Gas was caused by sodium bicarbonate, calcium chloride, and water.


Color was caused by the phenol red.


Heat was caused by calcium chloride and phenol red.


Cold was caused by sodium bicarbonate and phenol red.


Smell was caused by phenol red.





Post-lab Questions :)





1. the temperature change was caused by the calcium chloride and phenol red combining, causing heat, then sodium bicarbonate and phenol red combined and created coldness.





2. No, not particularly. When Emilie and I tested, we searched for particular categories (heat, cold, color... etc.)





3. The color started off as a magenta (or hot pink for all of you who don't know your colors), then turned orange-y yellow, then a bright yellow color. The yellow reminded me of a poisonous frog. The phenol red obviously was responsible for the color.





4. No, it wasn't observed at the same time. Sometimes we excluded the phenol red, so there was no color at all.





5. Reactions don't really occur unless there is a liquid to combine everything together.





6. The chemical changes-- like the different color, temperature, and odor.

7. You could take calcium chloride and water and mix them together to see if there's a reaction.

8. A temperature change doesn't indicates chemical change because it's something that can be reverted back to it's original state, like a physical change.