# chem and bme

1. Determine the force needed to separate a Na+ ion from a Cl ion and the separation distance at the point of maximum force if the ionic radius for Na+ is 0.18 nm and for Cl is 0.098 nm, the charge of each ion is 1.6×10-19 C, ε0=8.85×10-12 C2/Nm2 and m=9.
2. Use a computer program (like excel) to plot the force distance curve (F vs. r) for the attractive component, the repulsive component and the overall component (separate color line for each). Make sure that the scales of the axis are such that differences in each curve can be seen. Label your diagram to include the bond distance and maximum force (give the values for each). Figure quality counts.
3. Find an expression for the bond energy vs. distance. Note: include the ionization energy and electron affinity terms. Ionization energy for Na à Na+ is 5.14 eV and the electron affinity of Cl is 4.02 eV. HINT: You need to do a unit conversion so everything is in the same system of units.
4. Plot the bond energy vs. distance function (E vs. r). Label this diagram to show the repulsive energy curve, attractive energy curve, totally energy curve, bond energy, the bond distance.
5. What is the energy needed to separate these two ions? Give this in Joules.