When you saw the penny demo, the penny turned silver before it turned gold. The demo
used zinc, Zn (s), and zinc chloride, ZnCl, (aq).
Do you think the penny was coated with actual silver, Ag?

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.

d : a person who learns about the world by observing it. no that is not a smiley face

explanation: