A student collects oxygen gas by water displacement at a temperature of 17 Celsius. A barometer reads 92.3 kPa. What is the pressure of the water vapor? Look it up on a water vapor pressure chart. What is the pressure of the oxygen gas? (Answer: ~14.0 mmHg for water, 678.3 mmHg for oxygen)

Answer 1

TTL Pressure = 92.3KPa = (692mmHg)* = P(O2) + P(HOH)

From reference: P(HOH)=14mm @ 17d-Celcius

Therefore P(O2) = P(TTL) - P(HOH) = (692mmHg) - (14mmHg) = 678mmHg.
______________
*P(TTL) = 92.3KPa x (1000Pa/KPa) x (1Atm/101,325Pa) x (760mm/Atm) = 692mmHg Total Pressure