Question

How many molecules are contained in 0.254 moles of diarsenic trioxide

Answer 1

Answer:

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

$0.254 \hspace{3} mol \hspace{3} As_2O_3(\frac{6.02(10)^{23} \hspace{3} molecules \hspace{3} As_2O_3}{1 \hspace{3} mol \hspace{3} As_2O_3} )$ = 1.52908 × 10²³ molecules As₂O₃

Step 3: Simplify

We have 3 sig figs.

1.52908 × 10²³ molecules As₂O₃ ≈ 1.53 × 10²³ molecules As₂O₃