A scientist mixes Substance A with water and Substance B with water. Then she mixes the solutions of Substance A and B. A solid precipitate forms. The scientist wants to know whether the solid precipitate is evidence that a reaction took place. The properties of Substance A, B, and the precipitate are shown below.

Question

A scientist mixes Substance A with water and Substance B with water. Then she mixes the solutions of Substance A and B. A solid precipitate forms. The scientist wants to know whether the solid precipitate is evidence that a reaction took place. The properties of Substance A, B, and the precipitate are shown below.

Substance. Appearance. Dissolves Melting density
A white solid yes. 1,000 2.5
B. Blue-green solid yes. 500. 3.4
Precipitate blue-greensolid. No. 300. 3.3

Answer 1

Based on the information provided, it is likely that a chemical reaction took place when Substance A and Substance B were mixed together. This is indicated by the formation of a solid precipitate with different physical properties than the original substances. The fact that the precipitate does not dissolve in water and has a different melting point and density compared to Substance A and B suggests that a new substance was formed during the mixing process. Further analysis, such as chemical testing or spectroscopy, may be needed to confirm whether a chemical reaction occurred.