What did we do??

We put a bath bomb in a sealed bag and again in an open bag; we crushed both bath bombs to see if gas would escape from the bath bomb.

We also reacted bath bombs with water in a closed setting (sealed soda bottle) and an open setting (open soda bottle) to see if the gas was "new matter."

What have we proven so far??

We now know that the gas from the bath bomb was not trapped inside the bath bomb and was not "new matter." Instead, the gas comes from the substances that are there to begin - 

the water and the bath bomb.

What did we do??

In Lesson 3, we observed all ten ingredients of the homemade bath bombs and then observed each of them individually interacting with water.

Our results from Lesson 3 helped us introduce our investigation in Lesson 4, where we tested all of the combinations of pairs of ingredients in water. 

What have we proven so far??

We proved that the interaction between Citric Acid, Baking Soda, and water produced the bath bomb's bubbling/fizzing gas.

We also proved that the gas is a NEW SUBSTANCE but not new matter.

What did we do??

In Lesson 5, we used two properties of matter (flammability and density) to rule out gases on the Common Gas Data Table. 

We tested the flammability of the gas created by the bath bomb and found it is not flammable and extinguishes a flame.

We ruled out five gases that explode in the presence of a flame.

We then compared the density of the bath bomb gas to the air in the room around us and found bath bomb gas to be more dense. 

We ruled out two more gases from the five possible gases remaining.

What have we proven so far??

We proved the bath bomb gas could be:

Carbon Dioxide, Argon, or Nitrogen

What did we do??

We reviewed each lesson and added ideas to our model as we went through it. The additions to the model above are noted in the color coding of each lesson.

Lesson 2     Lesson 3     Lesson 4     Lesson 5

We brainstormed what could happen to the particles to create new substances. Teams created models to prepare for a gallery walk to share ideas.

After exploring the models we made in class, we completed Lesson 8, Reading about John Dalton, his exploration of gases in the atmosphere, and his depiction of particles. We also read that scientists in the past added different forms of energy to water and saw bubbles appear in the water. 

What did we do??

We used a reading to compare our models of particles in a chemical reaction to John Dalton's findings.

We also used molecular modeling kits to show the chemical reaction of electrolysis. We saw that two water molecules are needed to form one molecule of oxygen and two molecules of hydrogen. This was proven when we conducted the electrolysis lab and saw twice the amount of hydrogen gas collecting in one of the test tubes compared to half that amount of oxygen gas in the other test tube.

What did we learn??

We learned that the basic unit of all matter is an atom. About 118 different types of atoms can combine to form molecules. Some molecules can be made of more than one type of atom, and these are called compounds.

We also learned that a few things occur during a chemical reaction:

1. Bonds between atoms BREAK

2. Atoms REARRANGE

3. NEW BONDS Form between the atoms

EXPLANATION

The gas made from the bath bomb in water is carbon dioxide gas. 

First, from our lab experiences, we know that the gas made from the bath bomb is denser than room air and is not flammable. Based on the flammability and density data, we narrowed our choices of gas to three: carbon dioxide, argon, and nitrogen. 

The reaction's reactants are citric acid, baking soda, and water. Altogether, these substances contain only carbon, oxygen, hydrogen, and sodium atoms. We ruled out Argon and Nitrogen because the products and the reactants need to be made from the same atoms. None of the reactants contains Argon or Nitrogen atoms, so they must be disqualified. When we examined the reaction further, we learned that one sodium citrate molecule forms. It is made up of carbon, sodium, oxygen, and hydrogen atoms. We also know six water molecules (containing two hydrogen and one oxygen atom each) were produced in the reaction as products. Once the sodium citrate and water molecules were formed by rearranging the reactant molecules, we had carbon and oxygen atoms left over in a 1:2 ratio. This is the same ratio we find carbon and oxygen in when they form a carbon dioxide molecule. 

According to our scientific principles, the atoms from the reactants will be the same atoms in products, just rearranged. Atoms can’t be created or destroyed, and our answer reflects that no atoms were added or lost when they were rearranged in the reaction. Mass was conserved, and carbon dioxide properties matched the properties of the unknown gas. 

C6H8O7 + 3NaHCO3 + 3H2O     →     Na3C6H5O7 + 6H2O + 3CO2 

MATTER CANNOT BE CREATED OR DESTROYED

The mass of the reactants will always equal the mass of the products 

This is True in both Open and Closed Systems

In Open Systems, mass can escape, so it may appear to lose mass, but it truly has not. 

Be sure to scroll down on both docs since they are multi-page documents!