The number of vacancies in some hypothetical metal increases by a factor of 3 when the temperature is increased from 915 ˚C to 1160 ˚C. Calculate the energy for vacancy formation (in J/mol) assuming that the density of the metal remains the same over this temperature range.

For the closed feedwater heater below, feedwater enters state 3 at a pressure of 2000 psia and temperature of 420 °f at a rate of ix10 ibhr. the feedwat extracted steam enters state 1 at a pressure of 1000 psia and enthalpy of 1500 btu/lbm. the extracted er leaves at an enthalpy of 528.7 btu/lbm steam leaves as a saturated liquid. (16) a) determine the mass flow rate of the extraction steam used to heat the feedwater (10) b) determine the terminal temperature difference of the closed feedwater heater