How many molecules are contained in 0.254 moles of diarsenic trioxide

1.53 × 10²³ molecules As₂O₃

Explanation:

Step 1: Define

Diarsenic Trioxide - As₂O₃

Avagadro's number: 6.02 × 10²³ atoms, molecules, formula units, etc.

Step 2: Use Dimensional Analysis

= 1.52908 × 10²³ molecules As₂O₃

Step 3: Simplify

We have 3 sig figs.

1.52908 × 10²³ molecules As₂O₃ ≈ 1.53 × 10²³ molecules As₂O₃