• What possible variables have you not accounted for? As you did the procedures, is it possible that the atmospheric pressure may have changed? If it did change over the course of your experiment, then how would your results have been affected?

What do you not know about it

Answerδh > 0explanationc₆h₆  (s)  → c₆h₆ (l)if you are changing it from a solid to a liquid, you are pretty much melting the solid. this requires heat energy. therefore, the reaction is endothermic (takes in energy); the system enthalpy increases as the reaction proceeds: δh > 0.