After wood burns, the ash weighs much less than the original wood. Explain why the law of conservation of mass is not violated in this situation?

Explanation:

The law of conservation of mass and energy according to thermodynamics is NOT violated. The ash of the wood weighs less than the initial wood because during the burning some of the mass was converted to gases that escaped into the atmosphere. Some of the carbon in the wood, for example, turned to carbon dioxide. Water in the wood also turned to gas (water vapour) and escaped.

If it is possible to capture all these gases and weigh them, then ideally it would be observable that the law of conservation is NOT violated.

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.