5. One of eddies friends accidentally knocks the heavy book onto the floor it falls to the floor and makes a loud noise what do we know about the energy in this example there is no change in the form of energy energy is destroyed when the book makes a loud sound energy is created when the book is dropped energy is changed from one Form to another

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.