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Use the Kohler curves shown on the next page (from Wallace and Hobbs Fig. 6.3) t

ID: 3279213 • Letter: U

Question

Use the Kohler curves shown on the next page (from Wallace and Hobbs Fig. 6.3) to estimate a. The equilibrium radius of a solution droplet initially with radius of 0.05 m with mass of 4. 10-18 kg of NaCl in air that is 0.03% supersaturated (note supersaturation is equal to RH-100, so 101% RH = 1% supersaturation) The relative humidity of the air adjacent to a solution droplet with equilibrium radius of 0.1 pm that contains 10-19 kg of (NH)2SO, (ammonium sulfate, a common acrosol) The critical supersaturation % required for a solution droplet with 10-18 kg of (NH4)2SO4 to grow spontaneously by condensation b. c.

Explanation / Answer

a) The radius at which the Kohler Curve is a maximum is called Critical radius.

Curve 3 represents 10-18 kg of NaCl. So the radius corresponding to the maximum value of curve 3 is its Critical Radius.

Thus Critical Radius is around 0.6 um.

b) 10-19 kg of (NH4)2SO4 is represented by 5th line.

c) The Supersaturation % at Critical radius is called Critical Supersaturation %

10-18 kg of (NH4)2SO4 is represented by 6th line.

Thus, the Supersaturation % i.e. Supersaturation % at Critical radius is 0.15%