Question

Predict the sign of the system's entropy change in each of the following processes.

(a) Sodium chloride melts.

(b) A building is demolished.

(c) A volume of air is divided into three separate volumes of nitrogen, oxygen, and argon, each at the same pressure and temperature as the original air.

Short answer

(a) The sign of system's entropy change of melting of sodium chloride is positive.

(b) The sign of system's entropy change of demolishing of building is positive.

(c) The sign of system's entropy changes a volume of air is divided into three separate volumes of nitrogen, oxygen, and argon, each at the same pressure and temperature as the original air is negative.

Step-by-step solution

Given information

(a) Sodium chloride melts.

(b) A building is demolished.

(c) A volume of air is divided into three separate volumes of nitrogen, oxygen, and argon, each at the same pressure and temperature as the original air.

Concept of entropy of the system

Its entropyA thermodynamic system's state of disorder can change when heat or enthalpy is converted into work, which is referred to as change.

Anextremelydisorderedsystemhasgreaterentropythanamoreorderlyone.

Identify the sign of the entropy change when sodium chloride melts

(a)

Melting sodium chloride is the procedure.So sodium transitions from a solid to a liquid state.

Theatomsarearrangedinarigidframework,makingthesolidstatethemorefixedconditionbecauseitsentropyislower.

When considering the arrangement of the atoms, the liquid state is more random since the atoms are less tightly bound together.

Asaresult,asthevolumegrows,sodothemolecules'optionsforprobableplacements.Consequently,theentropychangewillbepositive.

Identify the sign of the entropy changewhen a building is demolished

(b)

The process is a building is demolished. The buildinghad a fixated and strict structure, so the entropy was low. When building is demolished then the number microstates available is increases. Therefore, the "mess" is increases. Therefore, the entrophy change is positive.

 Identify the sign of the entropy change for third option

(c)

The process is a sample of air divided into three separate volumes of nitrogen, oxygen, and argon, each at the same pressure and temperature as the original air. The three separate pure volumes of each elementis obtained after division of volume of air. The entropy in a mixture is higher than in a pure compound, therefore the entrophy change is negative.