Explain why the reaction between p-nitrofluorobenze and sodium methoxide results in a para substitution of the methoxy group.
Two factors contribute to the para substitution. First, the fluoro group gives additional resonance forms for substitutions occurring at the para position which stabilizes the Meischeimer Complex. Second, the C-F bond is polarized which encourages an attack of the methoxide at that carbon and the C-F polarity further stabilizes the Meischeimer Complex.
Explain how secondary active transport is used to bring Glucose into an intestinal absorptive cell from the lumen using a symporter.
To move glucose against its concentration gradient, a simultaneous movement of Na+ along its concentration gradient can be used. To establish a concentration gradient for Na+, the sodium-potassium pump is employed, resulting in a low [Na+] within the cell. As as result, [Na+] will move along its concentration gradient as it enters the cell. If this movement is then coupled to the movement of glucose using a symporter, glucose can overcome its concentration gradient.
Find the period of oscillation of a square block in water following an applied force, Fapplied. Derive T, where m is the mass of the block, A is the area of one face, and x is the distance the block in pushed down into the water. Assume non-damped oscillation.