Hi:) why do metals have free electrons? anyone able to explain the conduction part as well? Thanks!

Metals have free electrons due to the bonding in metallic substances.

In a metal there are strong attractive forces between the nuclei and the valance electrons.

Positively charged metal nuclei form a lattice (a cube like structure) each metal atom provides one or more valance electrons that are free to move throughout the lattice The electrons are attracted to the positively charged nuclei but not one individual nuclei, this is called non-directional bonding since it occurs in all directions.

Now all metals are conductive becuase of the free to move (delocalised) electrons. Since the valance electrons are free to move throughout the lattice they are able to carry a charge. (Ionic solids cannot since the ionic solids form a tightly packed lattice with cations and anions which have no free moving electrons, electrons have to be able to move to carry a charge)

i believe the answer is a

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.