In the following reaction, what element is gaining mass? Mg(s) + CuSO4(aq) -> MgSO4(aq) + Cu(s)

A. Mg
B. None of these
C. Cu
D. O

Mg gained mass because it went from being a single element (on the reactant side) to being a molecule (on the product side).

the dissolution of polymer can be thermodynamically described in 2 steps.

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.