Calculate the mass fraction of sulfur in lithium sulfate.

To solve this problem, we write down given: lithium sulfate (Li2SO4).
Find: mass fraction of sulfur in lithium sulfate.
Decision:
Let’s write down the formula for finding the mass fraction of an element in a substance.
w = n * Ar / Mr
n is the number of atoms or molecules.
Ar is the relative atomic mass.
Mr is the relative molecular weight.
Let’s calculate the relative molecular weight of the substance.
Mr (Li2SO4) = 7 * 2 + 32 + 16 * 4 = 110
Let’s plug the known data into the formula and make the calculation.
w (S) = 32/110 = 0.29 or 29%
Answer: 0.29 or 29%