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.