In small groups, think of ten ways we witness substances change in state every day. Present your findings to the class. Remember that condensation and melting are examples of changes of state. Condensation is the point of change from a gas to a liquid. Melting is the point of change from a solid to liquid. Evaporation is also a way that liquids change to gases.​

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.