Refrigerant flows in a copper tube of outer diameter of 4.8 cm. the inside surface temperature is -15 degree c and the room temperature is 20 degree c. the surface heat transfer coefficient between the tube and the room air is 25 w/m^2 middot k. ignore the thermal resistance of the copper tube, so that the outside wall temperature of the tube is the same as the inside wall temperature. 1) what is the heat gained by the refrigerant per unit length? 2) to reduce the heat gained from the room air, someone decided to put 4 mm of insulation (thermal conductivity 0.75 w/m middot k) around this tube. show that the heat loss per unit length actually increases after adding this insulation. 3) explain why you can expect the heat loss to increase.

Both 1,2−dihydronaphthalene and 1,4−dihydronaphthalene may be selectively hydrogenated to 1,2,3,4−tetrahydronaphthalene. one of these isomers has a heat of hydrogenation of 101 kj/mol (24.1 kcal/mol), and the heat of hydrogenation of the other is 113 kj/mol (27.1 kcal/mol). match the heat of hydrogenation with the appropriate dihydronaphthalene.

Electric charge is what ? a. kinetic energy b. radiation c. discovery d. electricity

You mix the pks of succinic acid are 4.21 and 5.64. how many gramsa graduate student at sdsu wants to measure the activity of a particular enzyme at ph 4.0. to buffer her reaction, she will use a buffer system based on one of the acids listed below, which acid is most appropriate for the experiment? of monosodium succinate (fw = 140 g/mol) and disodium succinate (fw = 162 g/mol) must be added to 1 l of water to produce a solution with a ph 5.28 and a total solute concentration of 100 mm? (assume the total volume remains 1 liter, answer in grams monosodium succinate, grams disodium succinate, respectively.) volumes of 0.05 m nah2po4 and 0.05 m na2hpo4 (pk's for phosphoric acid are 2.15, 6.82 and 12.38). which of the following best describes the resulting solution?