Question

A student puts his signature with graphite pencil. if the mass of carbon in the signature is 10^-12 g. calculate the no. of carbon atoms in the signature?

Answer 1

mass of carbon is 12 therefore moles are 10^-12 /12

in each mole their are 6*10^-23 atoms therfore atoms are approx 5 * 10^10 atoms

Answer 2

Answer:molecular wt of c=12

12g of c=6.022*10^23

1g of c= 6.032*10^23/12

Therefore,

10^-12g of c=6.022*10^-23*10^-12/12

=0.5*10^11 g

Explanation: