Question

If the atomic mass of sodium is $23,$ the number of moles in $46\,g$ of sodium is:

• A. $1$
• B. $2$
• C. $2.3$
• D. $4.6$

Answer 1

Answer: (B)

Number of moles of a substance is the ratio of its given mass and atomic or molar mass. In one mole of a substance the number of particles, atoms or molecules is equal to the Avogadro's number.
Number of moles of $Na=\frac{\text{given mass}}{\text{atomic mass}}$
Number of moles of $Na=\frac{46}{23}=2$
This means that the mass of $2$ $moles$ of sodium is equal to $46\,g$ .