A clear colorless liquid, Barium Chloride (BaCl), is added to a clear blue solution of copper sulfate (CuSO4). The
solution tums pale blue and cloudy. After a while, the
cloudy substance all sinks to the bottom of the test tube.
Physical or chemical change and explain.

the old alchemists made significant contributions to science even though there starting premises were off a bit. their conclusions after failure would steer them into better directions for investigation. science is no more than close observation and the initial mistakes result in rethinking and retrying experiments.

it's all four options.

i'm wiling to try and you : )