In the manufacture of nitric acid, ammonia and preheated air are mixed to form a gas containing 15.0 mole% nh3 at 600°c. after the blending process, the ammonia is catalytically oxidized to form no2, which is absorbed in water to form hno3. if ammonia enters the gas blending unit at 25°c at a rate of 520 kg/hour and heat is lost from the mixer to its surroundings at a rate of 7.00 kw, determine the temperature to which the air must be preheated.