Reaction In A Bag

Objective The student will be able to analyze a chemical reaction in order to explain the law of conservation of matter.

Recall the Law of Conservation of Matter (or Mass) The Law of Conservation of Matter states that during a chemical reaction, matter is neither created nor destroyed. In other words, the total amount of matter before and after a chemical reaction stays the same.

SILENTLY read the procedure. What is the purpose of this lab? Why is it necessary to make sure the bag is sealed tightly? In step I, it says to mass the rubber band with the bag, why?

Today we will be doing the following chemical reaction: 2NaHCO3 + CaCl2 -----> CaCO3  + 2NaCl  + H2O + CO2

Answer the following question on page 21: Based on what the Law of Conservation of Matter states, what do you think will happen to the mass after the chemical reaction between baking soda and calcium chloride occurs? (Will it increase, decrease or stay the same?) Explain your answer.

On Page 22 of your notebook, draw the following chart and title it “Reaction in a Bag Data” Mass of Materials before reaction Mass of Materials after reaction

Do the investigation

Clean-up Procedure Give the Ziploc bag to Mr. Hong. Make sure your station is neat and clean. Stack the goggles. Take your seat.

Read Conserving the Matter Complete “Life in a Jar Reflections 3”

Paste the “Reaction in a Bag analysis” on page 21. Paste the reading “Conserving Matter” on page 20 Paste “Life in a Jar Reflections 3” on page 23

Can you do an experiment with seltzer tablet and water to test the Law of conservation of matter? How will you keep the tablet from reacting with the water before you are ready? Does it matter how much water that you use?