Which has more molecules: 1.0 g of H2O or 1.0 g of H2O2? Why
because mole mass is less for H2O, then number is mass/molmass, so H2O has more more molecules (it is more moles)
To determine which substance, 1.0 g of H2O or 1.0 g of H2O2, has more molecules, we need to compare the number of molecules using their molar masses and Avogadro's number.
First, let's calculate the number of moles of each substance.
1.0 g of H2O:
The molar mass of H2O (water) is approximately 18.02 g/mol (hydrogen = 1.01 g/mol, oxygen = 16.00 g/mol).
Number of moles = mass / molar mass
Number of moles of H2O = 1.0 g / 18.02 g/mol ≈ 0.055 mol
1.0 g of H2O2:
The molar mass of H2O2 (hydrogen peroxide) is approximately 34.02 g/mol (hydrogen = 1.01 g/mol, oxygen = 16.00 g/mol).
Number of moles = mass / molar mass
Number of moles of H2O2 = 1.0 g / 34.02 g/mol ≈ 0.029 mol
Next, we need to use Avogadro's number to convert the number of moles into the number of molecules.
Avogadro's number (NA) is approximately 6.022 × 10^23 molecules/mol.
Number of molecules = number of moles × Avogadro's number
For H2O:
Number of molecules of H2O = 0.055 mol × 6.022 × 10^23 molecules/mol ≈ 3.31 × 10^22 molecules
For H2O2:
Number of molecules of H2O2 = 0.029 mol × 6.022 × 10^23 molecules/mol ≈ 1.75 × 10^22 molecules
Comparing the number of molecules, we find that 1.0 g of H2O contains more molecules than 1.0 g of H2O2.
Therefore, 1.0 g of H2O has more molecules than 1.0 g of H2O2.