I II
30. A substance composed of two or more
elements chemically combined is called a
mixture
BECAUSE
the properties of the constituents of a
mixture are retained.
31. A chemical change involves change in the
composition and molecular structure of the
reactants
BECAUSE
in a chemical reaction bonds are
broken and new substances and new
bonds are formed.
32. The burning of paper is a physical change
BECAUSE
when a chemical change occurs
energy is either gained or lost by the
reactants.
*Fill in oval CE only if II is a correct explanation of I.