Answer to Question #155015 in Chemistry for Dallas

Question

how many molecules are there in 19.99 g of H2O2?

Answer 1

Solution:

Moles of H₂O₂ = Mass of H₂O₂ / Molar mass of H₂O₂

The molar mass of H₂O₂ is 34.0147 g mol^-1.

Moles of H₂O₂ = 19.99 g / 34.0147 g mol^-1 = 0.5877 mol

One mole of any substance contains 6.022×10²³ atoms/molecules.

Hence,

Number of H₂O₂ molecules = 0.5877 mol × (6.022×10²³ molecules / 1 mol) = 3.539×10²³ molecules

Number of H₂O₂ molecules = 3.54×10²³ molecules

Answer: 3.54×10²³ molecules are there in 19.99 g of H₂O₂.