Question

you are running a reaction in lab. when you mix two solutions together, you notice that the flask grows warmer in your hand. what observation could you make about the reaction?

• the reaction is exothermic, because it is releasing heat to the surroundings.
• no observations about the nature of the reaction can be made without more information, like the temperature of the solutions.
• the reaction is endothermic, because it is absorbing heat from its surroundings.
• the reaction is exothermic, requiring thermal energy from its surroundings to continue.

Explanation:

To determine the nature of the reaction, we analyze the observation: the flask grows warmer. Exothermic reactions release heat into the surroundings, causing the surroundings (like the flask and the hand holding it) to feel warmer. Endothermic reactions absorb heat, which would make the surroundings feel cooler. The third option is incorrect because we have the observation of temperature change (warmer flask) to infer, and the fourth misdefines exothermic. So the first option correctly identifies the reaction as exothermic due to heat release to surroundings.

Answer:

A. The reaction is exothermic, because it is releasing heat to the surroundings.