Very ! i will rate
answer the following qs:
what causes day and night?
what causes seasons?
what causes stars and constellations to change position in the sky throughout the night?
except for circumpolar constellations, why don’t we see the same constellations at night throughout the year?
why doesn’t the north star change position (i. e., except over thousands of years)?

Consider the point on the plot where 10.0 g of naoh have been added. what amount of naoh, in moles, has been added? 0.308 mol fecl3 initially present

Calculate the molarity of 48.0 ml of 6.00 m h2so4 diluted to 0.250 l .

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.