If atmospheric pressure at lake tahoe is 649 torr, what will be the boiling point of water there?

The boiling point of water at lake Tahoe is 95.6°C.

The variation of boiling point of water with pressure is determined by using the Clausius- Clapeyron equation.

Here,

P₁ is the pressure at temperature T₁, P₂is the pressure at temperature T₂;ΔHvap is the enthalpy of vaporization of water,and R is the universal gas constant.

rewrite the expression for T₂.

The boiling point of water at atmospheric pressure of 760 torr is 373 K.

Substitute 760 torr for P₁, 649 torr for P₂, 373 K for T₁, 8.314 J/K mol for R and 40660 J/mol for Δ H_vap and simplify.

Express the temperature in Celcius.

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.