You can not see between opaque materials because light cannot pass through them.
Mg gained mass because it went from being a single element (on the reactant side) to being a molecule (on the product side).
When battery discharge / delivering current the lead at the anode is oxidized
that is ;
pb---->pb+ 2e-
since the lead ions are in presence of aquous sulfate in insoluble lead sulfate precipitate onto the electrode
the overall reaction at the anode is therefore
Pb + SO4^2- ---> PbSO4 + 2e-
Their valence electrons don't give them the ability to bond, they are also not in need to any electrons, since they won't get an octet soon.
To solve average speed? You can either make a quad or take your total distance and divide it by your total time/ and that would give you your total average speed! Your average speed would be Mp/H<span />
