The core of Earth is made out of iron and nickel. The outer core's
temperature is so hot that it melts the metal. The inner core is solid metal.
What causes these differences?

it would be d. henry moseley

hope this !

and sorry if i'm late. have a good rest of your day! : d

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.