Question

Indicate whether each of the following properties is a physical or chemical property of sodium:

a. Its density is greater than that of kerosene and less than that of water.
b. It has a lower melting point than most metals.
c. It is an excellent conductor of heat and electricity.
d. It is soft and can be easily cut with a knife.
e. Freshly cut sodium is shiny, but it rapidly tarnishes in contact with air.
f. It reacts very vigorously with water, releasing hydrogen gas.

Answer 1

The properties of sodium can be classified as physical or chemical. Sodium's density, melting point, and conductivity are physical properties, while its softness and ease of cutting, tarnishing in contact with air, and reactivity with water are chemical properties.

Step-by-step explanation:

a. The property stated is a physical property. Density is a physical property that describes how much mass is contained in a given volume. In this case, the density of sodium is being compared to the densities of kerosene and water.

b. The property stated is a physical property. Melting point is a physical property that describes the temperature at which a substance changes from a solid to a liquid state. In this case, the melting point of sodium is being compared to the melting points of other metals.

c. The property stated is a physical property. Conductivity is a physical property that describes the ability of a substance to conduct heat or electricity. In this case, sodium is described as being an excellent conductor of both heat and electricity.

d. The property stated is a physical property. Softness and ease of cutting with a knife are physical properties that describe the physical state and texture of a substance. In this case, sodium is described as being soft and easily cut.

e. The property stated is a chemical property. Tarnishing is a chemical property that describes the reaction of a substance with other substances, usually resulting in a change in appearance. In this case, sodium is described as tarnishing rapidly in contact with air.

f. The property stated is a chemical property. Reactivity with water is a chemical property that describes the ability of a substance to undergo a chemical reaction with water. In this case, sodium is described as reacting vigorously with water and releasing hydrogen gas.