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Molal Humidity Formula:
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Molal Humidity is defined as the ratio of moles of vapour (condensable) to the moles of dry (non-condensable) gas. It provides a measure of the moisture content in a gas mixture on a molar basis.
The calculator uses the Molal Humidity formula:
Where:
Explanation: This formula converts absolute humidity (mass basis) to molal humidity (molar basis) using the appropriate conversion factor.
Details: Molal humidity is particularly important in chemical engineering processes, air conditioning systems, and atmospheric studies where molar ratios are more relevant than mass ratios for certain calculations and process designs.
Tips: Enter absolute humidity in Kg of water vapour per Kg of air. The value must be valid (greater than 0).
Q1: What's the difference between absolute humidity and molal humidity?
A: Absolute humidity is measured on a mass basis (kg water/kg air), while molal humidity is measured on a molar basis (moles water/moles dry air).
Q2: Why is the constant 0.6207 used?
A: This constant represents the ratio of molecular weights (18/29 = 0.6207) used to convert from mass basis to molar basis.
Q3: When is molal humidity preferred over absolute humidity?
A: Molal humidity is preferred in chemical process calculations, gas mixing operations, and situations where molar balances are more convenient than mass balances.
Q4: Can molal humidity be greater than 1?
A: Yes, molal humidity can be greater than 1, indicating that there are more moles of water vapor than moles of dry air in the mixture.
Q5: How does temperature affect molal humidity?
A: While the conversion formula itself doesn't include temperature, absolute humidity is temperature-dependent, so molal humidity indirectly depends on temperature through the absolute humidity measurement.