1. The dissociation energy for a hydrogen-bromine bond is defined as the change in enthalpy, DH, for which of the following reactions?
2. The 1H Larmor frequency of benzene exceeds that of trifluoroacetic acid by 1.656 kHz on a 400 MHz spectrometer. The 1H chemical shift of benzene is 7.16 ppm. What is the chemical shift of trifluoroacetic acid?
3. The rotational correlation time of a spherical object of radius r immersed in a liquid with viscosity η is given by the Stokes equation: τc = 4πηr3/3kBT. A small molecule with relative molecular mass Mr = 100 in water at 298 K has τc = 50 ps. Assuming that Mr is proportional to the molecular volume, estimate τc for a small protein with Mr = 8400.
4. What is the ratio of line intensities in the EPR spectrum of the t-Bu radical (CH3)3C•?
5. Which nuclide has an NMR frequency of 115.5 MHz in a 20.0 T magnetic field?
