Question

A signature written with carbon pencil weighs 1 mg. What is the number of carbon atoms present in the signature?
A. `6.02xx10^(20)`
B. `0.502xx10^(20)`
C. `5.02xx10^(23)`
D. `5.02xx10^(20)`

Answer 1

Correct Answer - B
12 g of C-12 contain `6.02xx10^(23)` atoms
`10^(-3)` (1mg) of C-12 contain atoms
`= (6.02xx10^(23))/(12)xx10^(-3) = 0.502xx10^(20)`