The overall chemical equation is c(s) + h2o(g) to co(g) +h2(g) . to calculate the final enthalpy of the overall chemical equation, which step must occur?
reverse the first equation, and change the sign of the enthalpy. then, add.
reverse the second equation, and change the sign of the enthalpy. then, add.
multiply the first equation by three, and triple the enthalpy. then, add.
divide the third equation by two, and double the enthalpy. then, add.

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.