2.19 For a K+−Cl− ion pair, attractive and repulsive energies EA and ER, respectively, depend on the distance between the ions r, according to E A = − 1.436 r E R = 5.86 × 10 − 6 r 9 EA=−1.436rER=5.86×10−6r9 For these expressions, energies are expressed in electron volts per K+−Cl− pair, and r is the distance in nanometers. The net energy EN is just the sum of the preceding two expressions. (a) Superimpose on a single plot EN, ER, and EA versus r up to 1.0 nm. (b) On the basis of this plot, determine (i) the equilibrium spacing r0 between the K+ and Cl− ions, and (ii) the magnitude of the bonding energy E0 between the two ions.

Liquid flows at steady state at a rate of 2 lb/'s through a pump, which operates to raise the elevation of the liquid 100 ft from control volume inlet to exit. the liquid specific enthalpy at the inlet is 40.09 btu/lb and at the exit is 40.94 btub. the pump requires 3 btu/s of power to operate. if kinetic energy effects are negligible and gravitational acceleration is 32.174 tt/s, the heat transfer rate associated with this steady state process is most closely 1)-2,02 btu/s from the liquid to the surroundings 2)-3.98 btu/s from the surroundings to the liquid. 3)-4.96 btu/s from the surroundings to the liquid. 4)-1.04 btu/s from the liquid to the surroundings.