Question

If the atomic mass of carbon was set at 100 u, what would be the value of Avogadro's number ?

• A. $6.02\times 10^{23}$
• B. $6.02\times 10^{25}$
• C. $5.01\times 10^{24}$
• D. $6.02\times 10^{21}$

Answer 1

Answer: (C)

Mass of 1 atom of carbon $\left(C^{12}\right)=\frac{12}{6.02\times 10^{23}g}$
As the atomic mass of $C^{12}$ is $100u$ number of atoms present in $1g$ atom or $100g$ is Avogadro’s number on this scale
$\therefore$ Avogadro’s number $=\frac{100}{12/6.02\times 10^{23}}$
$=\frac{100\times 6.02\times 10^{23}}{12}$
$=5.01\times 10^{24}$