Question

1. students are testing the reactivity of different solutions by mixing them together, two at a time, and entering their observations in the table. the teacher tells the students that it is safe to touch the outside walls of the beakers to observe any temperature changes. the students produce the following data. table: trial 1: color change no, precipitate formed no, shape change yes, temperature change yes; trial 2: color change no, precipitate formed no, shape change yes, temperature change yes; trial 3: color change yes, precipitate formed yes, shape change no, temperature change no; trial 4: color change yes, precipitate formed yes, shape change yes, temperature change no which conclusions must be true of these data? select two correct answers. options: trial 1 and 4 formed a new substance because both trials resulted in a change in shape. trials 1 and 3 formed a new substance because both trials resulted in change in temperature. trials 2 and 3 formed a new substance because both trials resulted in a change in color. trials 3 and 4 formed a new substance because both trials resulted in a precipitate.

Explanation:

To solve this, we analyze each option by checking the table data:

Analyzing Option 1:

“Trial 1 and 4 formed a new substance because both trials resulted in a change in shape.”

• Trial 1: Shape Change = Yes, but Color Change = No, Precipitate Formed = No, Temperature Change = Yes.
• Trial 4: Shape Change = Yes, Color Change = Yes, Precipitate Formed = Yes, Temperature Change = No.

A new substance forms with chemical changes (precipitate, color, temp change). Trial 1 has no precipitate/color change, Trial 4 has them—but “change in shape” is physical. So this is incorrect.

Analyzing Option 2:

“Trials 1 and 3 formed a new substance because both trials resulted in change in temperature.”

• Trial 1: Temperature Change = Yes, but Color Change = No, Precipitate Formed = No, Shape Change = Yes.
• Trial 3: Temperature Change = No, Color Change = Yes, Precipitate Formed = Yes, Shape Change = No.

“Change in temperature” alone doesn’t confirm a new substance (physical changes can also change temp). Also, Trial 3 has no temp change. So this is incorrect.

Analyzing Option 3:

“Trials 2 and 3 formed a new substance because both trials resulted in a change in color.”

• Trial 2: Color Change = No, Precipitate Formed = No, Shape Change = Yes, Temperature Change = Yes.
• Trial 3: Color Change = Yes, Precipitate Formed = Yes, Shape Change = No, Temperature Change = No.

Trial 2 has no color change, so this is incorrect.

Analyzing Option 4:

“Trials 3 and 4 formed a new substance because both trials resulted in a precipitate.”

• Trial 3: Precipitate Formed = Yes, Color Change = Yes, Shape Change = No, Temperature Change = No.
• Trial 4: Precipitate Formed = Yes, Color Change = Yes, Shape Change = Yes, Temperature Change = No.

Precipitate formation is a chemical change (indicates new substance). Both trials have “Precipitate Formed = Yes.” This is correct.

(Note: Since the problem says “select TWO,” we recheck—likely a typo or missed option, but based on the table, Trials 3 and 4 (option 4) is correct. If another correct option exists, re-verify:

Wait, re-examining:

• Trial 3: Color (Yes), Precipitate (Yes) → chemical change (new substance).
• Trial 4: Color (Yes), Precipitate (Yes) → chemical change (new substance).

Another possible correct option: If there’s an option like “Trials 3 and 4 show chemical changes (new substance) due to precipitate/color change,” but from the visible options, the yellow-highlighted one (“Trials 3 and 4 formed a new substance because both trials resulted in a precipitate”) is correct.

Answer:

The correct option (from the visible choices) is: Trials 3 and 4 formed a new substance because both trials resulted in a precipitate (the yellow-highlighted option). If a second correct option exists, re-verify the table for another chemical change indicator (e.g., color + precipitate + temp/shape, but based on the given data, this is one valid conclusion).