Question

On a winter day you inhale cold air at a temperature of 13^(@)C and at 0% humidity.The amount of air you inhale is 0.2kg per hour.Inside your body you warm and humidify the air you then exhale the air at a temperature of 37^(@)C and 100% relative humidity.At a temperature of 37^(@)C each kilogram of air at 100% relative humidity contains 0.04kg of water vapor.X kcal are carried out of your body by the air that passes through your lungs in one hour.Find the X .Take into account both the heat needed to warm the air at constant pressure and the heat needed to vaporize the moisture that the exhaled air carries out of your body.The specific heat of air at constant pressure is 0.25kcal/^(@)C the heat of vaporization of water at 37^(@)C is 600kcal/kg .​

Answer 1

Answer:

The sound pressure levels (SPLs) of common infant humidifiers were determined to identify the likely sound exposure to infants and young children. This primary investigative research study was completed at a tertiary-level academic medical center otolaryngology and audiology laboratory. Five commercially available humidifiers were obtained from brick-and-mortar infant supply stores. Sound levels were measured at 20-, 100-, and 150-cm distances at all available humidifier settings. Two of 5 (40%) humidifiers tested had SPL readings greater than the recommended hospital infant nursery levels (50 dB) at distances up to 100 cm. In this preliminary study, it was demonstrated that humidifiers marketed for infant nurseries may produce appreciably high decibel levels. Further characterization of the effect of humidifier design on SPLs and further elucidation of ambient sound levels associated with hearing risk are necessary before definitive conclusions and recommendations can be made. © American Academy of

Answer 2

The value of X is dependent on the pressure and moisture that has been vaporized in the air.

step by step:

a) The temperature is 2°C and the relative humidity is 15% on a frigid winter day. You breathe air at a rate of 5500mL/min on average and exhale a water-saturated gas at body temperature, about 37°C.

b) What rate in J/day do you lose energy by breathing if the mass flow rates of inhaled and exhaled air (without water) are the same, the heat capacities (Cp) of the water-free gases are each 1.05 J/(g °C), and water is ingested into the body as a liquid at 22°C.

c) Treat breathing as though it were a continuous process (inhaled air and liquid water enter, exhaled breath leaves) and ignore the lungs' work.