Question

Mario places 10 mL of water in a test tube and heats the liquid over a Bunsen burner for 2 minutes. After removing the test tube from the Bunsen burner, there are 6 mL of water left in the test tube. This experiment is a good example of a
A.
chemical change involving phase changes.
B.
physical change involving phase changes.
C.
chemical change involving chemical reactions.
D.
physical change involving chemical reactions.

Answer 1

The experiment described involves heating water, which causes some of it to evaporate. The reduction in the volume of water from 10 mL to 6 mL indicates that the water has changed from a liquid to a vapor (steam), which is a phase change.

Since this process does not involve any change in the chemical composition of the water (H2O remains H2O), it is classified as a physical change.

Thus, the correct answer is:
**B. physical change involving phase changes.**