Final answer:
A chemical reaction occurs when an effervescent tablet is added to water in a balloon, inflating it due to gas production. The mass does not change because mass is conserved. Upon release, an air-filled balloon propels in the opposite direction due to Newton's third law, and a combustion reaction in a test tube can create a flame and a bang.
Step-by-step explanation:
When an effervescent tablet is added to water inside a balloon, a chemical reaction takes place, producing gas. This gas inflates the balloon, which can be observed by the expansion of the balloon. If the balloon is then placed in a flask and the total mass is measured before and after the reaction, one will notice that the mass remains constant. This demonstrates the law of conservation of mass, which states that mass is neither created nor destroyed in a chemical reaction.
In the context of the propulsion of a balloon experiment, when a balloon is filled with air and released, the air exits the balloon from the opening, propelling the balloon in the opposite direction due to Newton's third law of motion: for every action, there is an equal and opposite reaction. Filling the balloon with water and releasing it shows the same principle, although the balloon's movement may be less erratic due to the higher density and incompressibility of water compared to air.
If a burning match is held in the mouth of a test tube, one might observe a combustion reaction depending on the contents of the test tube. If the test tube contains a flammable gas, a flame and possibly a loud bang could be observed, indicating a rapid combustion reaction and the release of energy.