Question

What will be the mass of ${}^{12}C$ atom in g?

Answer 1

The mass number of an element is nothing but the molecular weight of the element. We can find the mass of one atom of an element by using the following formula.
$\text{Mass of one atom of an element = }\dfrac{\text{Atomic mass of the element}}{\text{Avogadro }\\!\\!'\\!\\!\text{ s number}}$
Avogadro number = $6.023\times {{10}^{23}}$ atoms.

Complete step by step answer:
- In the question it is given that to determine the mass of ${}^{12}C$ atoms in one gram.
- We know that mass of one mole of ${}^{12}C$ = $6.023\times {{10}^{23}}$ atoms of ${}^{12}C$
- Therefore the mass of $6.023\times {{10}^{23}}$ atoms of ${}^{12}C$ is 12 g.
- We can find the mass of one atom of ${}^{12}C$ by using the below formula.

& \text{Mass of one atom of an element = }\dfrac{\text{Atomic mass of the element}}{\text{Avogadro }\\!\\!'\\!\\!\text{ s number}} \\\ & =\dfrac{12}{6.023\times {{10}^{23}}} \\\ & =1.9927\times {{10}^{-23}}g \\\ \end{aligned}$$ **\- So, the mass of ${}^{12}C$ atoms in g is $=1.9927\times {{10}^{-23}}g$.** **Additional information:** \- ${}^{12}C$ is the main isotope of carbon. \- The atomic number of carbon is 6. \- The allotropic forms of carbon are diamond and graphite. \- Almost all organic compounds contain carbon as the main element. \- There is an isotope for carbon, ${}^{13}C$ . \- We can study the presence of carbon-13 by using Carbon-NMR spectroscopy. \- Without carbon there is no existence of organic compounds in nature. \- Always carbon exists in organic compounds as a combined form with hydrogen. **Note:** To determine the number of atoms in one mole of substance we should need the Avogadro number. By using Avogadro number only we can calculate the number atoms in one mole of any substance. Avogadro number or Avogadro constant both are the same. Both are going to represent the number of atoms in one mole of substance.