Which has a greater number of atoms: 3.0 g of iron, Fe, or 2.0 g of sulfur, S?

Question

Wyatt Atkins · Accepted Answer

#"2.0 g"# of sulfur

You must first ascertain the number of moles of each element present in order to calculate the number of atoms in those two samples. As you know, one mole of any element contains exactly #6.022 * 10^(23)# atoms of that element - this is known as Avogadro's number. The idea is that the difference between the mass of one mole of sulfur and one mole of iron is determined by the difference between the actual atoms of the two elements. Furthermore, the molar mass of an element will tell you the mass of one mole of said element. One mole of such atoms will be heavier the heavier the individual atom. Therefore, calculate how many moles of each you have using the molar masses of iron and sulfur. #"For Fe: " 3.0color(red)(cancel(color(black)("g"))) * "1 mole Fe"/(55.845color(red)(cancel(color(black)("g")))) = "0.0537 moles Fe"# #"For S: " 2.0color(red)(cancel(color(black)("g"))) * "1 mole S"/(32.065color(red)(cancel(color(black)("g")))) = "0.0624 moles S"# You will have more sulfur atoms since you have more moles of sulfur. In particular, the two samples will comprise #0.0537color(red)(cancel(color(black)("moles"))) * (6.022 * 10^(23)"atoms of Fe")/(1color(red)(cancel(color(black)("mole")))) = 3.23 * 10^(22)"atoms of Fe"# additionally #0.0624color(red)(cancel(color(black)("moles"))) * (6.022 * 10^(23)"atoms of S")/(1color(red)(cancel(color(black)("mole")))) = 3.76 * 10^(22)"atoms of S"#

Cameron Andrews · Answer

undefined 3.0 g of iron (Fe).