Classify each of the following changes as physical or chemical:
(a) condensation of steam
(b) burning of gasoline
(c) souring of milk
(d) dissolving of sugar in water
(e) melting of gold

An unknown substance was put in a container. the substance filled up the container from bottom up, taking half of the space in the container. what is most likely the state of matter of the substance? gas liquid plasma solid