Explain why pyrrole (pKa∼17) is a much stronger acid than ammonia (pKa=36). There are schemes of two reversible reactions. In the first reaction, the reactant is a five-membered ring, where a segment with four vertices is followed by an N atom (clockwise). There is a double bond between the first and the second and between the third and the fourth vertices. An H atom is attached to the N atom. The reactant gives a five-membered ring, where a segment with four vertices is followed by N, and H plus. There is a double bond between the first and the second and between the third and the fourth vertices of the ring. The N atom is negatively charged. The pKa value of the reactant is approximately equal to 17. In the second reaction, NH3 produces one equivalent of NH2 minus and one equivalent of H plus. The pKa value is equal to 36. Check all that apply. Check all that apply. Stabilizing the base decreases the acidity of its conjugate acid. Stabilizing the base increases the acidity of its conjugate acid. When pyrrole loses a proton, the electrons left behind remain on nitrogen. Electron delocalization stabilizes the anion and makes it heavier to form. Electron delocalization stabilizes the anion and makes it easier to form. When ammonia loses a proton, the electrons left behind remain on nitrogen. When ammonia loses a proton, the electrons left behind remain on another atom.

Show transcript transcripts online experiment: atomic structure [the history of atomic theory] this animation will you test rutherford’s hypothesis that it took a great number of shots to actually hit the nucleus because the size of the atom was so much larger than the nucleus.[clipboard and pencil with a diagram of rutherford’s gold foil experiment] we are going to use a cardboard box to represent the atom, a wooden block to represent the nucleus, and marbles to represent the alpha particles. [animated cardboard box, wooden block, and marbles] the box’s measurements are: length = 50 cm, width = 25 cm, and height = 25 cm. the measurements of the block are: length = 10 cm, width = 10 cm, and height is 5 cm. jose and priscilla will conduct the experiment. [animated boy and girl] priscilla put the block in the box on the floor. jose will close his eyes and drop marbles into the box trying to hit the block. priscilla will count the number of times the marbles hit the block and move the block in the box after each hit. [animated block moving inside the box. marble dropping into the box.] here is priscilla’s data of how many times the marble hit the block. out of 100 marble drops or shots, the marble hit the block 32 times. [data table: first column: marble, with rows 1 to 100; column 2: hit, with rows indicating yes or no. last row: total hits] now you can follow the directions in the experiment to present your findings. present your findings when you are finished with the experiment, complete the following data analysis and record your answers in the essay box below. determine the volume of the box and the block. determine the ratio of the block to the box: multiply this number by 100 to turn it into a percent. complete this statement: the volume of the block is percent of the volume of the box. determine the ratio of the number of hits to the number of shots: multiply this number by 100 to turn it into a percent. complete this statement: the block was hit percent of the time. compare the results of step 2 to the results of step 3. are the percentages similar? write a conclusion discussing the following items: based on your findings, do you think rutherford's hypothesis was reasonable? restate rutherford's hypothesis and describe how you tested it. state whether your results support the hypothesis. if they do not, can you suggest some error in experimental procedure (other than general human error) that might explain it? finally, explain how this experiment confirms the nuclear model of the atom and the idea that most of the atom is empty space.