Question

mixture begins to bubble. when the bubbling stops, trinity finds the mass of the mixture. she determines that the mixtures mass is 105 g. infer why the mass has changed. vinegar evaporated during the experiment baking soda loses mass when dissolved in vinegar mass was destroyed when vinegar reacted with baking soda a gas has formed and left the mixture

Explanation:

When vinegar (acetic acid) reacts with baking soda (sodium bicarbonate), a chemical reaction occurs. The reaction produces carbon dioxide gas ($\ce{CO2}$), among other products. The gas escapes from the mixture, which is why the mass of the mixture appears to decrease. This is in line with the law of conservation of mass, which states that mass is neither created nor destroyed in a chemical reaction. The mass is not lost but rather the gas product leaves the system (the mixture), so the measured mass of the remaining mixture is less.

• Vinegar evaporating would not be the main reason as the bubbling indicates a chemical reaction (production of gas) rather than simple evaporation.
• Baking soda does not just "lose mass" in a non - chemical dissolution sense as there is a chemical reaction happening.
• Mass is not "destroyed" as per the law of conservation of mass.

Answer:

A gas has formed and left the mixture.