Question

If $xg$ of $A$ (atomic mass $50$) contains $n$ atoms, how many atoms are there in $20xgB$ (atomic weight $100$)

• A. $n$
• B. $10n$
• C. $20n$
• D. $\frac{n}{10}$

Answer 1

Answer: (B)

$10n$

atoms $\times$ moles $=\frac{quantity\left(9m\right)}{atomicmass}=\frac{a}{A}$

$\Rightarrow \frac{n_1}{n_2}=\frac{a_1}{A_1}.\frac{A_2}{a_2}\Rightarrow \frac{n}{n_2}=\frac{x}{50}\times \frac{100}{20x}$

$\Rightarrow n_2=10n$ atoms