Question

A student used a carbon pencil to write his homework . b. the number of carbon atoms in 12 mg of his homework writing ​

Answer 1

Explanation:

no of atoms of carbon is 12*6.022*10‹23 atoms

Answer 2

Answer : The number of carbon atoms are, $6.022\times 10^{20}$

Explanation :

First we have to determine the moles of carbon.

Mass of carbon = 12 mg = 0.012 g    (1 mg = 0.001 g)

Molar mass of carbon = 12 g/mole

Formula used :

$\text{Moles of carbon}=\frac{\text{Mass of carbon}}{\text{Molar mass of carbon}}$

$\text{Moles of carbon}=\frac{0.012g}{12g/mole}=1\times 10^{-3}mole$

The moles of carbon in his homework writing is, $1\times 10^{-3}mole$

Now we have to determine the number of carbon atoms.

As, 1 mole of carbon contains $6.022\times 10^{23}$ number of carbon atoms

So, $1\times 10^{-3}$ mole of carbon contains $(1\times 10^{-3})\times (6.022\times 10^{23})=6.022\times 10^{20}$ number of carbon atoms

Therefore, the number of carbon atoms are, $6.022\times 10^{20}$