Select the reagent(s) that would efficiently convert the starting material to the product for the following transformations (if more than one reagent is needed, list them in order separated by commas with no spaces. for example, e, d,c). сhoose from reagents (a-l): a b c d ch3nh2, h h3o o3, dms h2so4, h2o, hgso4 e f g h pcc, ch2cl2 1) ch3mgbr 2) h2o h , hoch2ch2oh naoh i j k l 1) nh2nh2 2) koh, h2o, heat h , hsch2ch2sh 1) lah 2) h2o 1) ch3ch2mgbr 2) h2o

The scheme below is from a series of reactions that are part of a synthesis of vitamin a. answer the following questions with reference to this scheme. (i) what is "reagent a"? (ii) draw a step-by-step mechanism which explains the formation of compound c from compound b (iii) which reagents would you use to form compound e from compounds c and d (reagents b and c)? for each reagent suggested above in (ii) explain the role of the reagent in the reaction to (iv) form compound e. you may wish to do this by drawing a mechanism. 1. addition of reagent a но reagent a 2. н, о" thо oh нон-с compound a. compound b. compound c .ch-оh 1. reagent b "сно 2. reagent c сh oh compound e. compound d.

3. how much energy in joules is required to evaporate .0005 kg of liquid ammonia to vapor at the same temperature? 4. how much energy ( in megajoules ) is given up by .75 kg of water at 0c when it freezes to form ice at 0c? 5. explain how heat works between and at critical temperatures?

An alloy contains 66 g of pure zinc. what is the percentage of zinc in the alloy? express your answer to two significant figures and include the appropriate units.