Low melting points and lack of electrical conductor really are properties of molecule or compounds true or false

Look at the potential energy diagram for a chemical reaction. which statement correctly describes the energy changes that occur in the forward reaction?

An object of dimensions 50 cm x 40 cm x 0.20 cm has a mass 60g. find its density in g/cm3 and kg/ m3

Efficiency is the ratio of to for a system a)power in to power in b)power in to power out c) power out to power out d) power out to power in