Final answer:
To obtain 2.5 moles of iron for an experiment, you need to measure out 139.625 grams, using the atomic molar mass of iron which is 55.85 grams per mole.
Step-by-step explanation:
To determine the mass of iron (Fe) you must measure out to obtain 2.5 moles, you first need to know the atomic molar mass of iron. The molar mass of iron is 55.85 grams per mole. Therefore, you can calculate the mass required by multiplying the number of moles needed for your experiment by the molar mass of iron:
Mass of iron = Number of moles × Molar mass of iron
Mass of iron = 2.5 moles × 55.85 g/mol
Mass of iron = 139.625 grams
This is the amount of iron you would need to measure out for your experiment.