Answer: - 436.5 kJ.
Explanation:
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation.
The given chemical reaction is,
Now we have to determine the value of 
for the following reaction i.e,
According to the Hess’s law, if we divide the reaction by half then the will also get halved and on reversing the reaction , the sign of enthlapy changes.
So, the value 
for the reaction will be:
Hence, the value of for the reaction is -436.5 kJ.
I suck at chemistry but i have a friend that can help
Answer:
C
Explanation:
C because there is more in it than the rest of the idems
Answer:
If your asking why they are different because atoms are rearranged in a chemical reaction, there must be the same number of sodium atoms and chlorine atoms in both reactants and products for them to be the same.
Answer:
Just use a text book.. So that you get the concept
