Kepler’s second law of planetary motion states which of the following?
planets cover the same area during equal time periods while orbiting the sun. planets move at a constant speed around the sun.
planets move around the sun on the path of an ellipse.
the square of the orbital period of a planet is proportional to the cube of its average distance from the sun.

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.

In which reaction is precipitation occurring?

What is the equation for calculating rf values