Question

Two clear colorless solutions were combined, and the temperature changed from 25°C to 23°C. What most likely happened to produce these results?

a) One of the original compounds came out of the solution.
b) The solutions reacted chemically.
c) They underwent a physical change.
d) The temperature change was unrelated to the solutions.

Answer 1

The temperature change upon mixing two colorless solutions suggests a chemical reaction, specifically an endothermic reaction where heat is absorbed, causing a reduction in temperature.

Step-by-step explanation:

When two clear colorless solutions are combined resulting in a temperature change from 25°C to 23°C, the most likely cause of these results is b) The solutions reacted chemically. This temperature change indicates an endothermic reaction, where the system absorbs heat from the surroundings, thus causing the temperature to drop. This is in contrast to an exothermic reaction where the temperature would increase due to heat being released. No evidence of a physical change is provided, such as a color change or the formation of a precipitate, which would suggest a change in the physical state or appearance but not in the chemical composition.