Answer
a. physical
b. physical
c. physical
d. physical
e. chemical
f. chemical
Work Step by Step
a. physical: Density is a physical property of a substance.
b. physical: The melting point of a substance is a physical property.
c. physical: The ability to conduct heat and electricity is a physical property of a substance.
d. physical: Being soft is a physical property of a substance.
e. chemical: Tarnishing is a chemical property of sodium because it is the chemical reaction between sodium and the air, mainly with oxygen.
f. chemical: Reaction with water and producing hydrogen gas is a chemical property of sodium because it happens when sodium reacts with the oxygen in water molecules.