To determine the mass of iron (Fe) that would contain the same number of iron atoms as the number of molecules in 20.0 g of water (H2O), we need to follow these steps:
Calculate the number of water molecules:
- Determine the molar mass of water (H2O), which is approximately 18.015 g/mol.
- Calculate the number of moles in 20.0 g of water using the formula: Moles = Mass / Molar mass Moles = 20.0 g / 18.015 g/mol
- Convert the number of moles to the number of molecules using Avogadro's number (6.022 × 10^23 molecules/mol): Number of molecules = Moles * Avogadro's number
Determine the molar mass of iron (Fe):
- Look up the molar mass of iron on the periodic table. The molar mass of iron is approximately 55.845 g/mol.
Calculate the mass of iron:
- Divide the number of molecules of water by the number of iron atoms per molecule of water. Since there are two hydrogen (H) atoms and one oxygen (O) atom per water molecule, the number of iron atoms per molecule of water is 0.
- Multiply the number of iron atoms by the molar mass of iron to obtain the mass of iron: Mass of iron = (Number of molecules of water / Number of iron atoms per molecule of water) * Molar mass of iron
By following these steps, you can calculate the mass of iron required to contain the same number of iron atoms as the number of molecules in 20.0 g of water.