Error in Calculation of EDissolution?

[Aileen Gordola]

I calculated the Edissolution of a reaction and resulted in a negative number. However, during the wet lab the reaction was clearly endothermic since there was a drop in temperature. I used the equation:

∆Edissolution = Ccup∆Tcup/mass of salt

What is the reason for the negative number? Would i consider the negative sign as a mere drop in temperature and not as a factor contributing as to wether the reaction is endothermic or exothermic?

 

[Bystander]

I calculated the Edissolution of a reaction and resulted in a negative number.

Can you show us this calculation, please?

wether the reaction is endothermic or exothermic?

What do you know about endothermic and exothermic reactions?