Recall what was discussed in class regarding how to obtain avogadro's number from 1 u = 1.6605 x 10^-27 kg and the knowledge that 1 u = 1/12 of the mass of a carbon atom, and that 1 mol is equal to 12 g of carbon.
now compare avogadro's number to the number of stars in the milky way. start by assuming the milky way as a two dimensional plane (this is obviously not true but it's a close enough approximation, since the milky way is shaped like a disk). also take the shape of this plane to be that of a circle (also a close enough approximation for our purposes). if there are are an average of 8 stars per square light-year (also, this is on average--around our location, the nearest star is actually over 4 light years away; whereas near the central bulge, the density of stars is much greater than 8 per square light year) and the distance from the center to the edge of the milky way is about 100,000 light years, approximately how many stars are there in the milky way and how does this compare to avogadro's number?
avogadro's number is about double the number of stars in the milky way
the number of stars in the milky way is about twice that of avogadro's number
the number of stars in the milky way is about 1012 greater than avogadro's number
avogadro's number is about 1012 greater than the number of stars in the milky way