0.001 g of C is required to write a letter with a graphite pencil. The total number of C atoms used in writing the letter is

Options

A. `5.00xx10^(12)`
B. `5xx10^(19)`
C. `5.0xx10^(24)`
D. `6.023xx10^(23)`

Answer

B

Explanation

Atoms present in 1 mole (i.e. 12 g of C)
`=6.022xx10^(23)`
Thus, atoms present in 0.001 g of C
`=(6.022xx10^(23))/(12)xx0.001=0.5xx10^(20)` atoms.
`=5xx10^(19)` atoms.