Question

Calculate the mass in atomic mass units of 0.25 mol of carbon-12 atoms

Answer 1

Each C-12 atom weights 12 amu 
1mol = 6.02*10^23 atoms
6.02*10^23 * 0.25 * 12 = 1.806*10^24

Answer 2

Answer : The mass of carbon-12 atoms is, 3 amu

Solution : Given,

Moles of carbon-12 atoms = 0.25 moles

The molar mass of carbon-12 atoms = 12 g/mole = 12 amu

(1 amu = 1 gram/mole)

Now we have to calculate the mass of carbon-12 atoms.

$\text{Mass of carbon-12}=\text{Moles of carbon-12}\times \text{Molar mass of carbon-12}$

Now put all the given values in this formula, we get the mass of carbon-12 atoms.

$\text{Mass of carbon-12}=(0.25moles)\times (12amu)=3amu$

Therefore, the mass of carbon-12 atoms is, 3 amu