What is the boiling point of water at an elevation of 5500 ft ? the vapor pressu

Question

What is the boiling point of water at an elevation of 5500 ft ?

the vapor pressure of a substance describes how readily molecules at the surface of the substance enter the gaseous phase. At the boiling point of a liquid, the liquid's vapor pressure is equal to or greater than the atmospheric pressure exerted on the surface of the liquid. Since the atmospheric pressure at higher elevations is lower than at sea level, the boiling point of water decreases as the elevation increases. The atmospheric pressure at sea level is 760 mmHg. This pressure decreases by 19.8 mmHg for every 1000-ft increase in elevation. Elevation Pressure 0 ft 760 mmHg 1000 ft 740.2 mmHg 2000 ft 720.4 mmHg The boiling point of water decreases 0.05C for every 1 mmHg drop in atmospheric pressure.

Explanation / Answer

Atm. pressure at sea level = 760 mmHg

Pressure decrease for every 1000-ft elevation = 19.8 mmHg

Decrease in pressure at 5500 ft = elevation (in 1000-ft) x pressure decrease per 1000-ft = 5.5 x 19.8 = 108.9 mmHg

So, pressure at 5500 ft = pressure at sea level - decrease in pressure = 760 - (5.5 x 19.8) = 651.1 mmHg

Boiling point of water at sea level = 100oC

Decrease in boiling point for every 1 mmHg drop in pressure = 0.05oC / mmHg

Decrease in boiling point for 108.9 mmHg drop in pressure = 0.05oC/mmHg x 108.9 mmHg = 5.445oC

So, boiling point of water at 5500 ft elevation = boiling point at sea level - decrease in boiling point = 100 - 5.445 = 94.555oC

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.