Consider the heating curve for water. At what temperature does the solid start melting? –20°C 0°C 20°C 80°C

0°C

Explanation:

The melting point of water - the temperature at which solid water begins to melt - is 0°C at a pressure of 1 atm. In the heating curve of water, below 0°C we have solid water. Then, at 0°C the solid water starts to melt by forming liquid water. Above 0°C, when the total amount of water is in the liquid state, the liquid water begins to heat (it increases its temperature).

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.

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