Question

select the correct answer.
justin mixed two clear liquids together during an experiment and made the following observations:

• the mixed liquids decreased in temperature without any refrigeration or other action to change the temperature.
• the color of the liquid changed to blue.

which statement best describes justin’s experiment?
a. a physical change occurred, and this caused the liquid’s chemical properties to change.
b. a chemical change occurred, and this caused the liquid’s physical properties to change.
c. a physical change occurred, so only physical properties changed.
d. a chemical change occurred, so only chemical properties changed.

Explanation:

1. Analyze the observations: Temperature decrease (a physical property change) and color change (a sign of chemical change, as new substances might form).
2. Recall definitions: A chemical change involves new substance formation (indicated by color change here), and during a chemical change, physical properties (like temperature, color) of the resulting substances can change.
3. Evaluate options:

• Option A: Physical change doesn't cause chemical properties to change; incorrect.
• Option B: Chemical change (color change, new substance) occurred, and physical properties (temperature, color) changed; correct.
• Option C: Color change is a chemical change sign, not physical; incorrect.
• Option D: Chemical change can cause physical properties to change too, not only chemical; incorrect.

Answer:

B. A chemical change occurred, and this caused the liquid’s physical properties to change.