Water-Vapor Capacity of Air Any measure of water vapor in the air is referred to as humidity. The amount of water vapor required for saturation is directly related to temperature. The

mass of water vapor in a unit of air compared to the remaining mass of dry air is referred to as the mixing ratio. Table 14.2 presents the mixing ratios of saturated air (water vapor needed for saturation) at various temperatures. Use the table to answer questions 1-3. Table 14.2 Amount of water vapor needed to saturate a kilogram of air at various temperatures, the saturation mixing ratio. a. 35°C: b. 59°F: TEMPERATURE (°C) -40 -30 -20 -10 c. 5°C: d. -30°C: 0 5 10 15 20 25 30 35 40 (°F) -40 -22 -4 14 32 41 50 59 68 77 86 95 104 WATER VAPOR CONTENT AT SATURATION (G/KG) 0.1 0.3 0.75 2 SONGS 3.5 5 7 10 14 20 26.5 35 1. To illustrate the relation between the amount of water vapor needed for saturation and temperature, prepare a graph by plotting the data from Table 14.2 on Figure 14.5. 47 2. From Table 14.2 and/or Figure 14.5, what is the water vapor content at saturation of a kilogram of air at each of the following temperatures? grams/kilogram grams/kilogram grams/kilogram grams/kilogram 3. From Table 14.2, raising the air temperature of a kilogram of air 10°C, from 10°C to 20°C, (increases, decreases) the amount of water vapor needed for saturation by (3, 7) grams./nWater Vapor Content at Saturation (g/kg) -40° -22° -4° 50 40 30 20 10 40° -30° -20° Temperature (°F) 32° 50° 14° 10° -10° 0° Temperature (°C) 68° 20° 86° 104° 30° 40°