Assignment Question
1) Calculate the theoretical yield of stilbene dibromide in part A, based on the actual amounts of reagents used. The purity of stilbene is 96%; that of the perbromide is 90%. Show all your work. (This is a limiting reactant problem.)
2) State the mass of stilbene dibromide obtained and calculate the percent yield.
3) Look at the equation for the diphenylacetylene reaction (part B). In the workup, thoroughwashing with water removes three substances from the diphenylacetylene, one of which is the solvent. What starting material is removed? What product is removed? Why does water remove these?
4) Calculate the theoretical yield of your diphenylacetylene synthesis based on the mass ofstilbene dibromide actually used. Assume that the purity of the stilbene dibromide is 100%.Show all work.
5) State the mass of your recrystallized diphenylacetylene and determine the percent yield,showing your work.
6) The overall percent yield for a multistep synthesis can be calculated by multiplying thedecimal equivalent of percent yield for each step together and then multiplying by 100 to get the overall yield. Determine the overall percent yield for your two-step synthesis ofdiphenylacetylene, where step 1 was the synthesis of meso-stilbene dibromide from E-stilbene and step 2 was the preparation of diphenylacetylene from meso-stilbene dibromide.
