Video Transcript
If you know that soda contains carbonic acid which decomposes to water and carbon dioxide gas, what will happen to the mass of a bottle of soda if you leave it open on the table?
We are told in the question that soda contains carbonic acid. We are also told that carbonic acid decomposes to water and carbon dioxide gas. We can represent this with a chemical equation in which carbonic acid is the reactant and water and carbon dioxide are the products. This question asks about the mass of a bottle of soda in which this reaction occurs. We can use the law of conservation of mass to help us answer the question.
The law of conservation of mass states that mass is neither created nor destroyed during a chemical reaction. In other words, the mass of the reactants must be equal to the mass of the products. Therefore, according to the law of conservation of mass, the mass of the carbonic acid must equal the mass of the water plus the mass of the carbon dioxide produced. So, if the reaction takes place inside of a closed bottle of soda, the mass of the bottle of soda will remain the same. But the question asks what would happen to the mass if the bottle was left open.
One of the products of this reaction is a gas. If the bottle is opened, the carbon dioxide gas can escape. So even though the law of conservation of mass is obeyed, if the bottle is open, one of the products will no longer be present in the bottle and the mass of the bottle of soda will be lower. Therefore, if a bottle of soda is left open on the table, its mass will decrease.
