To a 25.00 mL volumetric flask, a lab technician adds a 0.250 g sample of a weak monoprotic acid, HA , and dilutes to the mark with distilled water. The technician then titrates this weak acid solution with 0.0846 M KOH . She reaches the endpoint after adding 46.83 mL of the KOH solution. Determine the number of moles of the weak acid in the solution.

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.

As air becomes more dense, (select all that apply) o. air weighs less o. gas molecules are closer together o. air is colder o. air weighs more o. gas molecules are further apart o. air is hotter

In which reaction is precipitation occurring?