What is the mass in grams of 100 atoms of the Carbon -12 isotope?

Answer 1

here's some info for you
"As a matter of fact, the carbon-12 atom was
chosen as a basis for relationships between all
other atoms. The mass of a carbon atom was
divided into 12 parts, and each part is known as
atomic mass unit.
12 grams of a carbon atom corresponds to an
gram-atom and contains, according to Amedeo Avogadro,
6,022 x 10^23 atoms. That means, a single carbon
atom has the mass of ca. 1,99 x 10^ -23 grams.
This number, divided in 12 parts (= amu) gives
1,6605 x 10^ -24 g."

I gather from this that since a single carbon atom has the mass listed, that 100 atoms would have the mass of 1.99 x 10^-21 grams.

Answer 2

12 grams will contin 6.022*1023 atoms
100 atoms will have a mass of
=(100/6.022*1023)*12 grams
=199.27*10^-23 grams
=1.9927*10^(-21)grams

Answer 3

(1/Avogadro's number)*12*100
((1 / 6.02300) / (10^23)) * 12 * 100 = 1.99236261 × 10-21
or take the value of u from http://physics.nist.gov/cgi-bin/cuu/Value?ukg
multiply it by 1000
multiply it by 12
multiply it by 100
apply uncertainity