Question

A scientist pours a white powder into a beaker containing a clear liquid. The image shows a page from the scientist’s notebook.

image

Which statement BEST explains the type of change that occurred?

A.
A chemical change occurred because some of the liquid evaporated.

B.
A physical change occurred because the liquid remained clear.

C.
A physical change occurred because the temperature did not increase.

D.
A chemical change occurred because the mixture produced a gas.

Answer 1

D. A chemical change occurred because the mixture produced a gas.

Gas evolution (bubbling/fizzing) is evidence of a chemical reaction. Evaporation, lack of temperature change, or clarity of a solution do not reliably indicate a chemical change.