Question

One atom of an element weighs $3.32\times 10^{23}\, g$. How many number of gram atoms are there in $20\, kg$ of the element?

• A. $2000$
• B. $20$
• C. $200$
• D. $1000$

Answer 1

Answer: (D)

$1000$

Answer 2

Atomic mass of an element = Mass of one atom $\times N_A$ $= 3.32\times 10^{23} \times 6.023 \times 10^{23} = 19.99 \approx 20\, g$ No. of gram atoms $\frac{\text{Mass of element in grams }}{\text{Atomic mass in grams }}$ $=\frac{ 20\times 1000}{20} = 1000$