A2 m x 1.5 m section of wall of an industrial furnace burning natural gas is not insulated, and the temperature at the outer surface of this section is measured to be 80°c. the temperature of the furnace room is 30°c, and the combined convection and radiation heat transfer coefficient at the surface of the outer furnace is 10 wm2.°c. it is proposed to insulate this section of the furnace wall with glass wool insulation (k 0.038 wm c) in order to reduce the heat loss by 90%. assuming the outer surface temperature of the metal section still remains at about 80°c, determine the thickness of the insulation that needs to be used

it is the most commonly accepted one

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.