Students are studying how two substances react. The students mix substance 1 with substance 2 in a solution. Later the students
boil the solution, releasing substance 1 as a gas and leaving substance 2 as a solid. What type of change is described in the paragraph above? How do you know? This is a chemical change, because the two substances were mixed together.
This is a chemical change, because the two substances were separated chemically by boiling.
This is a physical change, because the two substances were separated physically by boiling.
This is a chemical change, because a gas was released.
Cooling a substance causes molecules to slow down and get slightly closer together, occupying a smaller volume that results in an increase in density. ... Cold water is more dense and will sink in room-temperature water.
