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

For a research project, a student decided to test the effect of the lead(ii) ion (pb2+) on the ability of salmon eggs to hatch. this ion was obtainable from the water‐soluble salt, lead(ii) nitrate, which the student decided to make by the following reaction. pbo(s) + 2 hno3(aq) → pb(no3)2(aq) + h2o losses of product for various reasons were expected, and a yield of 86.0% was expected. in order to have 5.00 g of product at this yield, how many grams of pbo should be reacted? (assume that sufficient nitric acid, hno3, would be used.)