Asample of dried appanoose county coal has a mass analysis of 71.1% carbon, 5.1% hydrogen(h_2), 9% oxygen (o_2), 1.4% nitrogen (n_2), 5.8% sulfur, and the rest noncombustile ash. for ocmplete combustion with the theoretical amount of air, determine

a) amount of so_2 produced, in kg per kg of coal
b) the air-fuel ratio on a mass basis

The temperature of air decreases as it is compressed by an adiabatic compressor. a)- true b)- false

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?

What is the heat treatment of metals? what is the benefit of it? why and how it's useful? answer in details, do not write by hand.