Question #51110
1 Answer
Number of atoms:
Number of molecules:
Explanation:
The question wants you to determine how many molecules and how many atoms of sulfur you get in
The important thing to know here is that sulfur atoms form octatomic molecules, which are molecules that contain
So, if it takes
Now, in order to be able to determine how many molecules of sulfur you're dealing, you first need to determine how many moles of sulfur you get in that mass.
This is why they give you sulfur's molar mass, which is equal to
This means that
#192color(red)(cancel(color(black)("g"))) * "1 mole S"/(32color(red)(cancel(color(black)("g")))) = "6.00 moles S"#
Next, use Avogadro's number to figure out how many
So,
#6.00color(red)(cancel(color(black)("moles S"))) * (6.022 * 10^(23)"atoms")/(1color(red)(cancel(color(black)("mole S")))) = color(green)(|bar(ul(color(white)(a/a)color(black)(3.61 * 10^(24)"atoms S")color(white)(a/a)|)))#
Finally, use the fact that you need
#3.61 * 10^(24)color(red)(cancel(color(black)("atoms S"))) * "1 molecule S"_8/(8color(red)(cancel(color(black)("atoms S")))) = color(green)(|bar(ul(color(white)(a/a)color(black)(4.51 * 10^(23)"molecules of S"_8)color(white)(a/a)|)))#
The answers are rounded to three sig figs, the number of sig figs you gave for the mass of sulfur.
So remember, you can go from mass to moles by using molar mass, then from moles to molecules / atoms by using Avogadro's number.