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Water Vapor Molar Mass:
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The molar mass of water vapor (H₂O) is the mass of one mole of water molecules in gaseous state. It is a fundamental physical constant used in chemistry, physics, and engineering calculations involving water vapor properties and behavior.
The calculator provides the constant molar mass value:
Where:
Explanation: This value represents the mass of one mole (6.022 × 10²³ molecules) of water vapor, calculated from the atomic masses of hydrogen (1.008 g/mol) and oxygen (16.00 g/mol).
Details: Knowing the molar mass of water vapor is essential for gas law calculations, humidity measurements, atmospheric science, chemical reactions involving water vapor, and engineering applications like HVAC design and combustion analysis.
Tips: Simply click the Calculate button to retrieve the constant molar mass value of water vapor. The calculator provides the precise value used in scientific calculations.
Q1: Why is the molar mass 18.015 g/mol and not 18 g/mol?
A: The value 18.015 g/mol accounts for the natural isotopic distribution of hydrogen and oxygen atoms, providing greater accuracy for precise scientific calculations.
Q2: Does water vapor have the same molar mass as liquid water?
A: Yes, the molar mass is identical (18.015 g/mol) regardless of physical state, as it depends only on molecular composition.
Q3: How is this value used in ideal gas law calculations?
A: It's used to convert between mass and moles: n = m/M, where n is moles, m is mass, and M is molar mass (18.015 g/mol for water vapor).
Q4: What factors can affect water vapor calculations?
A: While molar mass is constant, actual behavior may vary with temperature, pressure, and humidity levels in real-world applications.
Q5: Is this value used in meteorological calculations?
A: Yes, extensively in calculating vapor pressure, relative humidity, dew point, and other atmospheric parameters.