If the heat of reaction is negative, the reaction is select one: a. positive b. exothermic c. endothermic d. negative

Option (b) is the correct answer.

Explanation:

A chemical reaction where heat energy is absorbed by the reactant molecules is known as an endothermic reaction.  

For example,

The value of = +ve for an endothermic reaction.

In an endothermic reaction, heat being absorbed is utilized to break the bonds. Therefore, temperature of the system decreases.  

On the other hand, a chemical reaction in which heat energy is released by the reactant molecules is known as an exothermic reaction.  

The value of = -ve for an exothermic reaction.

Thus, we can conclude that if the heat of reaction is negative, the reaction is exothermic.

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !

58750.08068 is the answer i think