Answer:
~26 atoms of sulfur
Explanation:
When working problems involving equations I find it helpful to works through moles because it relates to the coefficients of balanced equation by linear ratio. In other words, convert data to moles, solve by ratio and convert results to desired dimensions. In this case Atoms of Sulfur.
Given: 52 atoms K = 52 atoms/6.02 x 10²³atoms K/mole K = 9.64 x 10⁻²³ mole K atoms.
Using ratios in given equation 4K + 2S => 2K₂S
Says
4 moles K reacts with 2 moles Sulfur, then
8.64 x 10⁻²³ mole K reacts with X moles Sulfur
Set up ratio:
(4 moles K) / (8.64 x 10⁻²³ moles K) = (2 moles S) / X
Solve for X => X = (2 moles S x 8.64 x 10⁻²³ mole K) / 4 mole K = 4.32 x 10⁻²³ mole S used
Converting moles S to atoms S, multiply by Avogadro's Number ...
Atoms S used = 4.32 x 10⁻²³ mole S used x 6.02 x 10²³ Atoms S / mole S
=> 26.0064 Atoms S ≈ 26 Atoms Sulfur used.
Note: This is a reasonable answer in that the balanced equation given indicates that half the number moles S reacts with K. So, one can conclude that half the number of potassium atoms would indicate the number of sulfur atoms needed. test => ¹/₂(52) = 26 atoms S.
