20 pts. hydrogen and oxygen react to form water. a. write the complete balanced equation. b. if 4 moles of hydrogen react with 4 moles of oxygen which of these is the limiting reagent? show work or explain how you know. c. what is the maximum amount of water (in grams) that can be produced given 4 moles of hydrogen and 4 moles of oxygen? show work.

Consider the following system at equilibrium. caco3(s) ca2+(aq) + co32–(aq) the addition of which compound will cause a shift in equilibrium because of a common ion effect? ccl4 co2 cuso4 na2co3

This is a characteristic of the elements in the periodic table that shows a pattern. it may increase or decrease across or down the table.

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.