sorry about the terrible title I couldn't think of a more descriptive one without making the message irrelevant

Ok in AS chemistry we are doing enthalpies and Exo/endothermic reactions, I understand this and can do the equations and work it out etc

What I can't do is get the answer the right way round for example I will write the enthalpy change of a reaction as 286 and the answer is -286

now I know there is a way to work this out correctly and teachers and peers have explained repeatedly how to do so and I just don't get it, for some reason it will not click

So after lots of searching (I even posted a thread here but got no answers) I discovered I can get it right!ifI know whether the reaction is exothermic or endothermic

Now this is great except I don't always get the information to work out if it's exo or endo, and I don't have the lifespan to memorise every reaction

so is there a way to work out if a reaction is exothermic or endothermic without any information save for the equation and state symbols

So hypothetically

NaOH + PbS2 -> H2O + NaPbS (I made it up so don't compain it's not balanced or even exists) is it exo or endo?