Which mineral has a metallic luster? a. gold b. quartz c. feldspar d. diamond

Option (A) is the correct answer.

Explanation:

Metallic luster is defined as the shine present on the surface of metals. Since, metals contain more number of electrons and in order to get stabilized they need to lose their valence electrons.

Therefore, when they are placed in light then these electrons get excited and as a result, the surface of metal appears shiny.

So, out of the given options only gold is also a metal whereas quartz, feldspar, and diamond are all minerals and not metals.

Thus, we can conclude that out of the given options gold has a metallic luster.

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.