Answer
(a) Physical change
(b) Chemical change
(c) Physical change
(d) chemical change
Work Step by Step
(a) A copper wire is hammered flat is a physical change because the composition has not changed. This makes it a physical property.
(b) A nickel dissolves in acid to form a blue-green solution is a chemical change. This makes it a chemical property.
(c) Dry ice sublimes without melting is a physical change because it is only changing properties, not composition. This makes it a physical property.
(d) A match ignites when struck on a flint is a chemical change because it changes its composition to a flame. This makes it a chemical property.
