Alkyl halides undergo nucleophilic substitution and elimination reactions. When the kinetics of the reaction are measured, if the rate of the reaction is found to be dependent upon the concentration of the nucleophile as well as the alkyl halide the reaction is second order. The substitution reaction is thus termed SN2, and the elimination reaction is termed E2. These reactions are bimolecular and take place in a single step. In the SN2 reaction, the nucleophile attacks the α-carbon from the backside and displaces the leaving group with an inversion of configuration occurring at the carbon. In the E2 elimination reaction, strong base removes an acidic hydrogen from the B-carbon and an alkene is formed as the leaving group is expelled from the α-carbon. This elimination follows Zaitsev’s rule whereby the more substituted alkene is generally formed. In E2 elimination, both the B-hydrogen and the leaving group must be oriented anti to each other. The same reaction conditions apply for both SN2 and E2, therefore these reactions often compete. Use of a strong, hindered base will tend to favor elimination, while use of a weak base/strong nucleophile will favor substitution. Draw curved arrows to show the movement of electrons in this step of the mechanism. Arrow-pushing Instructions

answer

the ions in solute supperate from eachouthere

what is the average time it took the car to travel 0.25 meters?

⇒ 2.23 seconds

what is the average time it took the car to travel 0.50 meters?

⇒ 3.13 seconds

most historians agree that gabriel mouton, the vicar of st. paul’s church in lyons, france, is the “founding father” of the metric system. he proposed a decimal system of measurement in 1670. mouton based it on the length of one minute of arc of a great circle of the earth (now called a nautical mile, 1852 meters). he also proposed the swing-length of a pendulum with a frequency of one beat per second as the unit of length (about 25 cm). a pendulum beating with this length would have been fairly easy to produce, thus facilitating the widespread distribution of uniform standards. over the years, his work was revised, improved, and extended by a number of french scientists.

the political sponsor of weights and measures reform in the french revolutionary national assembly was the bishop of autun, better known as talleyrand. under his auspices, the french academy appointed several committees to carry out the work of developing a usable system of weights and measures for france. one of the committees recommended a decimalized measurement system based upon a length equal to one ten-millionth of the length of a quadrant of the earth’s meridian (i.e., one ten-millionth of the distance between the equator and the north pole).