Chemical Reactions!!

Chemical reactions!  Exothermic?  Endothermic?

In science today, we created a chemical reaction mixing sodium bicarbonate (baking soda) and calcium chloride with water or phenol red.

CaCl2 + 2 NaHCO3 → 2 NaCl + CaCO3 + H2O + CO2(g)

That is the balanced equation of the chemical reaction that took place.

Here are some observable changes that occurred when we mixed the calcium chloride and sodium bicarbonate:

• change in temperature (increase)
• change in color
• change in state

We tested the items separately to see what was creating the change in temperature and recorded our responses:

• calcium chloride + water
• calcium chloride + phenol red
• sodium bicarbonate + water
• sodium bicarbonate + phenol red

We realized that calcium chloride mixed with a liquid has an exothermic reaction, heating up the product and that sodium bicarbonate with a liquid actually cools down, also creating an exothermic reaction.

Taking it a little further, we were looking at the effect of adding carbon dioxide to the mixture - will that cause a change?  Blowing with a straw into the mixed chemicals, we realized that it also created a chemical reaction - the solution heated up.

It was a lot of fun!  And a wonderful idea to share with the students!! :)