Question

Number of atoms of He in 100 amu of He (atomic wt. of He is 4) are:

• A. 25
• B. 100
• C. 50
• D. \( 10^6 \times 10^{-23} \)

Hint:

To find the number of atoms, divide the mass of the sample by the atomic mass and multiply by Avogadro's number.

Answer 1

The Correct Option is A

Step 1: Number of atoms.
The number of atoms can be calculated using the formula: \[ \text{Number of atoms} = \frac{\text{Mass of sample}}{\text{Atomic mass}} \times N_A \] where \( N_A \) is Avogadro's number. Substituting the given values, the result is 25 atoms.
Thus, the correct answer is (1).