Answer
a. Physical process
b. chemical reaction
c. physical processes
d. chemical reaction
e. physical process
Work Step by Step
a. Evaporation of a liquid into its gas form is a physical process. By evaporating water from the sea water, water changes its status from liquid into water vapor. In this process, water retains its chemical identity. At the same time, sodium chloride retains its chemical identity as it undergoes no changes.
Therefore it is a physical process to obtain sodium chloride from evaporating water of seawater.
b. Heating of mercury (II) oxide would produce mercury and oxygen. Mercury and oxygen are two distinguished chemical substances. Thus a chemical reaction has occurred, as two new chemical substances are formed from heating mercury (II) oxide.
c. There are two physical processes involved in this statement: 1st physical process is the evaporation of water from sea water into water vapor. Water changes its form from liquid to vapor but retains its chemical identity.
2nd physical process: condensing of water vapor into water liquid. This is again a physical process as water retains its chemical identity.
d. Iron ore that contains iron (III) oxide is transformed into iron through a chemical reaction because a new chemical substance ( iron) is formed from iron (III) oxide.
e. Gold settles in the flowing water. This is a physical process as gold retains its chemical identity.
