How does Lewis Dot Structures can be used to show reactions between different chemical elements

How much would the freezing point of water decrease if 4 mol of sugar were added to 1 kg of water(k=1.86 c/mol/kg for water and i=1 for sugar

Is a pencil falling to the floor anon contact force, a force, or a contact force

Rank the four gases (air, exhaled air, gas produced from from decomposition of h2o2, gas from decomposition of nahco3) in order of increasing concentration of co2