High School

Hikers climbing Mount Everest discovered it took much longer to cook a boiled egg than it does at sea level because the boiling water is not as hot. The \(\Delta H_{\text{vap}}\) of water is 40.7 kJ/mol. Atmospheric pressure at sea level is 760 torr. \(R = 8.314 \times 10^{-3} \text{ kJ/mol·K}\). Calculate the temperature of boiling water (in °C) at an atmospheric pressure of 615 torr.

a) 93.5 °C
b) 98.3 °C
c) 100.2 °C
d) 105.8 °C

Answer :

Final answer:

Explain how to calculate the boiling point of water at a specific pressure .Therefore, option a) 93.5 °C is the correct answer.

Explanation:

To calculate the temperature to boil water at a place with 0.7 atm pressure, we can use the Clausius–Clapeyron equation:

T2 = -ΔHvap / (R * ln(p2 / p1))

where T2 is the temperature to be calculated, ΔHvap is the heat of vaporization of water, R is the ideal gas constant, and p1 and p2 are the initial and final pressures respectively.

Substitute the values and solve to get the temperature which is approximately 93.5°C.

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