Astandard schedule 40, 2-in. steel pipe (inside diameter 2.067 in., and wall thickness 0.154 in.) carrying steam is insulated with 2 in. of 85% magnesia covered in turn with 2 in. of cork.
estimate the heat loss per hour per foot of pipe if the inner surface of the pipe is at 250°f and the outer surface of the cork is at 90°f. the thermal conductivities (in btu∕hr * ft * °f) of the substances concerned are:
steel, 26.1; 85% magnesia, 0.04; cork, 0.03

hi my dude or dudette

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.