Answer:
Step-by-step explanation:
Using Dalton's law of partial pressure
P total pressure = Pressure of helium + Pressure of neon + Vapor pressure of water
P = 28.3 mmHg, Pressure of helium = 381 mmHg, Vapor pressure of water at 28°C
791 mmHg - 381 mmHg - 28.3 mmHg = Pressure of neon
Pressure of neon = 381.7 mmHg