The number average molecular weight (Mn) of polyethylene glycol (PEG) can be determined in the following manner: (i) a sample of PEG is combined with excess phthalic anhydride and imidazole, and the mixture is allowed to react completely; (ii) once the reaction is complete, H2O is added to the mixtures; (iii) the mixture is titrated with NaOH.

Select the correct location on the image identify the element that humans need to breathe. 2015 er r ights reserved

How many grams of sodium chloride are in 250ml of a 2.5m naci solution

Astudent made the lewis dot diagram of a compound as shown. mg is written with two dots shown on its top. an o is written on each side of mg. each o has six dots around it. an arrow is shown from one dot on mg toward the vacant space around the o on the right. another arrow is shown from the other dot on mg toward the vacant space around the o on the left. the title of the art is students lewis dot model. what is the error in the lewis dot diagram? an o atom should transfer all its six electrons to mg because the formula is mgo. both electrons of mg should be transferred to one o atom because the formula is mgo. the electrons should be transferred from each o atom to mg because mg has fewer electrons. the number of dots around mg should be four because it has to transfer two electrons to each o.