Question

Thank you for your rich explanation,but.....

I don't get how "In this case both reactions are exothermic and the total is exothermic BUT both could be positive, both negative, or one each to give a final equation that is either + or - (or zero) however it turns out".

How come BOTH "could be positive".........

Is it not shown clearly that they are both negative?????

Answer 1

Perhaps it would have been better to have left that statement off since it has nothing to do with the problem at hand. I was simply trying to point out that although both were negative in this particular problem and the total was negative in this particular problem that IN SOME OTHER problem that could be different. Some problems you work, and it all depends upon those dH values, you COULD end up with different signs; i.e., two could end up +, two could end up - or you can have them mixed (one positive and one negative).