Question

1. a student measures the masses of two liquids. one liquid is 14 grams and the other liquid is 18 grams. then the student pours both liquids into an open beaker and observes the liquid bubble for a few minutes. when she measures the mass of the liquid in the beaker it has a mass of 29 grams. this could be because molecules ________. a. got smaller. b. escaped from the beaker. c. were destroyed. d. moved closer together. (nacl) through a chemical reaction

Explanation:

1. First, calculate the initial total mass of the two liquids: \(14 + 18 = 32\) grams. The final mass is 29 grams, so there is a mass loss.
2. Analyze each option:

• Option A: Molecules don't "get smaller" in a way that reduces mass; mass is conserved at the molecular level unless matter is lost. Eliminate A.
• Option B: If molecules escaped (e.g., evaporation, since the beaker is open), mass would decrease. This matches the mass loss (32→29).
• Option C: Molecules aren't destroyed in a physical process (mixing and bubbling, likely physical like evaporation); mass conservation in chemistry says matter isn't destroyed. Eliminate C.
• Option D: Molecules moving closer (like condensation) would not reduce mass; in fact, if gas (from bubbling) condensed, mass might stay or increase. Eliminate D.

Answer:

B. escaped from the beaker.