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.

a rain shadow is a dry region of land on the side that is protected against the prevailing winds of a mountain range. the prevailing winds are the winds that occur most of the time in a particular place of the earth

prevailing winds carry air toward the mountain range. as the air rises up over a mountain range, the air cools, water vapor condenses, and clouds form. on this side of the mountains, called the windward side, precipitation falls in the form of  rain  or snow. this dry air produces a  rain shadow.

answer: mole of the gas

answer: mole of the gasexplanation:

weight of any object is given by

w = m*g

where m is mass of the object and g is the acceleration due to gravity.

for earth the value of g is 9.8 m/s^2 so

w=117.6 n m=12 g=?

117.6=12g => g=9.8 m/s^2

which is the force of gravity on earth.