Ammonium phosphate NH43PO4 is an important ingredient in many fertilizers. It can be made by reacting phosphoric acid H3PO4 with ammonia NH3.
What mass of ammonium phosphate is produced by the reaction of 2.5g of phosphoric acid?
Be sure your answer has the correct number of significant digits.

B. a graduated substance

Your question is not clear but if you can explain yourself i would be glad to .  just trying to : ))

The internal energy of the system we can term it as total potential energy and kinetic energy. energy flows out of the surrounding from the system then we can say that the internal energy of the final state is lower than its initials. the sign of  δesystem is negative.δesystem = efinal - einitial=-ve  efinal  ∠einitial.