Fifty pounds of cotton cloth containing 20% total moisture content (dry basis) are hung in a closed room containing 4,000 ft³ of air at 1 atm. Initially, the air is at 100°F at a wet-bulb temperature of 69°F. If the air is kept at 100°F, without admitting new air or venting the air, and the air is brought to equilibrium with the cotton cloth, determine the moisture content of the cotton cloth and the relative humidity of the air. Assume that the equilibrium-moisture content for cotton cloth at 100°F is the same as that of glue at 25°C as shown in figure. Neglect the effect of the increase in air pressure, but calculate the final air pressure.

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1- paper, newsprint 2- wool, worsted 3- nitrocellulose 4- silk 5- leather, sole, oak tanned 6- kaolin 7- N.C. tobacco leaf 0.28 0.24 8- soap 9- glue 10 - lumber 0.20 0.16 10, 0.12 0.08 0.04 40 60 80 100 20 Percent relative humidity Moisture content in solids, Ib water/lb dry solids