Question

One atom of an element $X$ weighs $6.664\times {10}^{-23}gm$, then what is the number of gram atoms in 40 kg of it?

• A. 10
• B. 100
• C. 10000
• D. 1000

Answer 1

Answer: (D)

1000

Gram atomic mass = mass of 1 mole atoms$\times$ mass of one atom

$=(6.022\times {10}^{23})\times (6.664\times {10}^{-23})=40.01gm$

$Gramatoms=moles=mass/molarmass=40000/40=1000$

$\therefore$ The number of gram atoms in 40kg = 1000

Hence, the correct option is $C$