Phenylacetic acid has a pKa of 4.31; acetic acid has a pKa of 4.76. (a) Which acid has the more favorable (smaller) standard free energy of dissociation? (b) What free energy would be expended to dissociate a 1 M solution of phenylacetic acid completely into 1 M of its conjugate base and 1 M H3O+? (c) What is the fraction of phenylacetic acid that is ionized if it is dissolved in water and the pH is adjusted to 4.5 with NaOH? (d) If equal molar amounts of phenylacetic acid and acetic acid are dissolved in water and the pH is adjusted to 4.5 with NaOH, which acid is more dissociated? Explain. (e) According to the pKa data, which type of polar effect is characteristic of the phenyl group: an electronwithdrawing polar effect or an electron-donating polar effect? Explain your reasoning.
9/16/14 Biopsychology II: Drugs and their Effects The brain has 4 lobes: o Frontal: movement, primary motor control o Parietal: touch, voluntary, sensory, movement o Temporal: auditory-language o Occipital: vision Left hemisphere controls the right side (processes language) Right hemisphere controls the left side o Neglect syndrome: damage to right hemisphere at parietal/occipital junction o Phantom sensation: perception of a missing limb Somatic sensory map: begin receiving information from adjacent areas when missing a limb Principles in Biopsychology Localized functions Topographical Organization: map of body Contralateral Projections Plasticity: ongoing wiring of brain Key