the heat of fusion for water is the amount of energy that must be absorbed for water to

evaporate
boil
freeze
melt

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

Why does a plastic bottle that is sealed at a high altitude change it’s shape when taken to lower altitude

Ammonium perchlorate nh4clo4 is the solid rocket fuel used by the u.s. space shuttle. it reacts with itself to produce nitrogen gas n2 , chlorine gas cl2 , oxygen gas o2 , water h2o , and a great deal of energy. what mass of nitrogen gas is produced by the reaction of 2.1g of ammonium perchlorate?