Estimate the lower heating value of a typical cord of wood by first estimating the mass of the wood and then assuming that this mass is completely composed of cellulose (Problem 9.16). Compare your answer with the standard value of 26 GJ. Real “dried” fire wood(density 670 kg/m3) contains a significant amount of water in addition to cellulose (and lignin and hemi cellulose).When it burns, the water must be driven off as vapor. Compute the fraction y of water by mass in fire wood that would account for the discrepancy you found in the first part of this problem.