Solve this multiple-choice question and choose the correct option.

ConceptThe two common gas constants are related by molecular mass (M): Universal gas constant: R ≈ 8.314 kJ/(kmol·K) = 8,314 J/(mol·K) Specific gas constant (per unit mass): Rspecific = R / M RelationshipR = M × Rspecific Common pitfallsDo not confuse molar mass units (kg/kmol or g/mol) with mass units; ensure consistency so that R and Rspecific align dimensionally. Final AnswerTrue

Home » Mechanical Engineering » Thermodynamics

Universal gas constant vs. specific gas constant: verify the relationship Statement: The universal gas constant of a gas equals the product of the gas’s molecular mass and its (specific) gas constant per unit mass. Choose whether the statement is correct or not.

Difficulty: Easy

True
False

Correct Answer: True

Explanation:

ConceptThe two common gas constants are related by molecular mass (M):

Universal gas constant: R ≈ 8.314 kJ/(kmol·K) = 8,314 J/(mol·K)
Specific gas constant (per unit mass): R_specific = R / M

RelationshipR = M × R_specific

Common pitfallsDo not confuse molar mass units (kg/kmol or g/mol) with mass units; ensure consistency so that R and R_specific align dimensionally.

Final AnswerTrue

← Previous Question Next Question→

More Questions from Thermodynamics

Isothermal process law: identify the governing gas law For an isothermal (constant-temperature) process of an ideal gas, select the correct law that applies. Choose the correct option.
Thermal efficiency comparison: Stirling cycle versus Carnot cycle State how the efficiency of the (reversible, regenerator-based) Stirling cycle compares with a Carnot cycle operating between the same temperature limits. Choose the correct relationship.
Second law of thermodynamics – Kelvin–Planck statement Which of the following correctly expresses the Kelvin–Planck statement of the second law of thermodynamics for heat engines operating in a cycle?
Thermodynamic diagrams – area under the T–s curve On a temperature–entropy (T–s) diagram, the area under the process curve between two entropy states represents which thermodynamic quantity for that process?
Perfect gas relationships – Boyle’s law identification For a perfect gas, which relation expresses Boyle’s law when absolute temperature T is held constant (isothermal process)?
Gay–Lussac (pressure) law – proportionality at constant volume According to the pressure law, the absolute pressure of a fixed mass of a perfect gas varies __________ with its absolute temperature when the volume is held constant.
Air-Standard Diesel Cycle – Parameters Governing Thermal Efficiency In the ideal (air-standard) Diesel cycle, the thermal efficiency primarily depends on the compression ratio as well as the cut-off ratio (for a given specific heat ratio of the working gas).
First Law for a Closed Gas System (General Gas Energy Equation) Between states 1 and 2, the heat supplied equals the change in internal energy plus the work done: Q1–2 = dU + W1–2 (with consistent heat units).
Air-Standard Dual (Mixed) Combustion Cycle – Process Count Check The ideal dual combustion cycle comprises two isentropic processes, two constant-volume processes (heat addition and heat rejection), and one constant-pressure process (part of the heat addition).
Thermal Equilibrium Transitivity – Name of the Law If two bodies are each in thermal equilibrium with a third body, then they are in thermal equilibrium with each other. This fundamental statement is known as the Zeroth law of thermodynamics.

Discussion & Comments

No comments yet. Be the first to comment!

Join Discussion