Question

The number of carbon atoms in 12 mg of his homework writing

Answer 1

Answer:

no. of atoms = weight * avagadro no. / atomic weight

weight is given 12*10-³ g

atomic weight of carbon is 12

no. of atoms= 12*10-³ * 6.02*10²³/12

no. of atoms = 6.02 * 10^20

Answer 2

Answer: The number of carbon atoms in given amount of mass is $6.022\times 10^{20}$

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Given mass of carbon = 12 mg = $12\times 10^{-3}g$   (Conversion factor: 1g = 1000 mg)

Molar mass of carbon = 12 g/mol

Putting values in above equation, we get:

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

According to mole concept:

1 mole of an element contains $6.022\times 10^{23}$ number of atoms.

So, $1\times 10^{-3}$ moles of carbon will contain = $1\times 10^{-3}\times 6.022\times 10^{23}=6.022\times 10^{20}$ number of atoms.

Hence, the number of carbon atoms in given amount of mass is $6.022\times 10^{20}$