What happened to the number of moles in a sample that originally occupied 500ml with 2.50 moles and then occupied 750ml?
it deals with gas laws

The number of moles that initially occupied a 250ml container remains the same when it occupied 750ml container but they are freer because the 750ml container is bigger and has more space. So the gases now occupied more space and their movement is less curtailed unlike when they were in 250ml container

since electrons are negative the answer is neagtaive

water and alcohols have similar properties because water molecules contain hydroxyl groups that can form hydrogen bonds with other water molecules and with alcohol molecules, and likewise alcohol molecules can form hydrogen bonds with other alcohol molecules as well as with water.