4. Find the number if molecule in 40 gams of hydrogen peroxide H_(2)O_(2)

To find the number of molecules in 40 grams of hydrogen peroxide (H₂O₂), we need to follow these steps:<br /><br />1. **Calculate the molar mass of H₂O₂:**<br /> - Hydrogen (H): 1.01 g/mol<br /> - Oxygen ( 16.00 g/mol<br /><br /> Molar mass of H₂O₂ = (2 × 1.01) + (2 × 16.00) = 34.02 g/mol<br /><br />2. **Convert grams to moles:**<br /> - Moles = Mass / Molar Mass<br /> - Moles of H₂O₂ = 40 g / 34.02 g/mol ≈ 1.176 moles<br /><br />3. **Use Avogadro's number to find the number of molecules:**<br /> - Avogadro's number = 6.022 × 10²³ molecules/mol<br /><br /> Number of molecules = Moles × Avogadro's number<br /> Number of molecules = 1.176 moles × 6.022 × 10²³ molecules/mol ≈ 7.08 × 10²³ molecules, there are approximately 7.08 × 10²³ molecules of hydrogen peroxide (H₂O₂) in 40 grams.