Definition check — specific volume In fluid properties, the “specific volume” is defined as which of the following?

Introduction / Context:Thermodynamics and fluid mechanics frequently use intensive properties that are independent of system size. Specific volume is such a property and is the reciprocal of density. Understanding its definition aids in state calculations and property table lookups.

Given Data / Assumptions:

• Standard SI units: volume in m^3, mass in kg.
• Density ρ = mass/volume; specific volume v = volume/mass.

Concept / Approach:Specific volume v is defined as volume per unit mass: v = V / m. Since density ρ = m / V, it follows that v = 1 / ρ. It applies to liquids and gases alike and is especially convenient for compressible substances where density changes appreciably with pressure and temperature.

Step-by-Step Solution:Start with density ρ = m / V.Take the reciprocal: V / m = 1 / ρ.Recognize that V / m is the specific volume v.Therefore, the correct definition is “volume per unit mass.”

Verification / Alternative check:Typical SI unit check: If ρ is kg/m^3, then v has units m^3/kg, confirming the definition. Property tables (e.g., for steam) list specific volume in m^3/kg.

Why Other Options Are Wrong:

• Mass per unit volume → density, not specific volume.
• Weight per unit volume → specific weight (γ), different property.
• Volume per unit weight → sometimes called specific volume per weight (rare), not the standard definition used in SI property tables.

Common Pitfalls:

• Confusing density, specific volume, and specific weight because of similar names; always check dimensional units.

Final Answer:Volume per unit mass of a liquid or gas