Question

cover the flask with a balloon, and their reactants, baking soda and vinegar. then the mixture bubbles. when the bubbling stops, they table shows their data. baking soda mass (g): 1; vinegar: 5; flask: 55; balloon: 9; mass of system after reaction: 70. which valid conclusion is best supported by the data? a. mass is conserved during a chemical reaction. b. the mass of the equipment is always greater than the mass of the reactants. c. bubbles form when a clear liquid mixes with a white powder in a sealed container. d. baking soda and vinegar can also exist as gases and fill up a balloon that is sealing a system.

Explanation:

To determine the valid conclusion, we analyze each option:

• Option A: Calculate the total mass of reactants and equipment before the reaction. Baking soda (1g) + Vinegar (5g) + Flask (55g) + Balloon (9g) = 1 + 5 + 55 + 9 = 70g. The mass after the reaction is also 70g. This shows mass is conserved in the chemical reaction (baking soda + vinegar), supporting the law of conservation of mass.
• Option B: The mass of equipment (flask 55g + balloon 9g = 64g) and reactants (1g + 5g = 6g) – equipment mass is greater here, but this isn't a general rule (e.g., large reactants could have more mass than small equipment), so B is invalid.
• Option C: The observation of bubbles is a fact here, but the question asks for a conclusion supported by the mass data. The data focuses on mass conservation, not the observation of bubbles, so C is not supported by the data.
• Option D: Baking soda (solid) and vinegar (liquid) react to produce a gas (like CO₂) that fills the balloon, but the data about mass conservation doesn't support this statement about their states; the mass data is about conservation, not the state change of reactants.

Answer:

A. Mass is conserved during a chemical reaction.