Question

How many atoms of carbon are present in a diamond weighing $0.5$ carat? (one carat weighs $200\, mg$ and assume the diamond to be pure carbon)

• A. $5 \times 10^{21}$
• B. $6 \times 10^{22}$
• C. $7 \times 10^{19}$
• D. $8 \times 10^{12}$

Answer 1

Answer: (A)

carat $=200 \,mg$

$0.5$ carat $=100 \,mg$

1 mole of $C$ -atoms weight $=12 \,g$

$\Rightarrow 12\, g$ of carbon $=6.023 \times 10^{23} C$ -atoms

$ \Rightarrow 100 \,g $ of carbon

$=\frac{6.023 \times 10^{23} \times 100}{12 \times 1000}$

$=5.02 \times 10^{21} $