alleryStart learning →A gas collected over water is a mixture. How is the pressure of the dry gas found?
AAdd the water vapour pressure to it
BSubtract the water vapour pressure
CHalve the total measured pressure
DMultiply by the water mole fraction
Answer & Solution
Correct answer: B. Subtract the water vapour pressure
1. A gas bubbled up through water arrives saturated with water vapour.
2. By Dalton's law the measured total is the gas pressure plus the water vapour pressure.
3. So the dry gas pressure is the total minus the vapour pressure of water at that temperature.
4. The vapour pressure depends only on the temperature, and is looked up in a table rather than calculated.
_Source: OpenStax Chemistry (CC BY 4.0), Ch 9 "Gases", section 9.3 Stoichiometry of Gaseous Substances, Mixtures, and Reactions_
Keep practising Gases
Browse all Gases questions for IMU CET, or explore more Chemistry topics.
Related questions
The van der Waals equation reduces to PV = nRT under which condition?A 4.25 L flask holds 3.46 mol of carbon dioxide at 229 degrees C. What pressure does the iIn the van der Waals equation, what does the constant b account for?Who developed the first and simplest equation that improves on the ideal gas law?Under which conditions does a real gas behave most nearly like an ideal gas?For a gas showing perfectly ideal behaviour, the compressibility factor Z takes which valuKinetic molecular theory explains Boyle's law by which change when the volume of a gas decAt a fixed temperature, how do lighter gas molecules compare with heavier ones?