Calculate in witch material - sodium or zinc sulphide is the highest percentage by mass of sulfur

sodium sulphide.

Explanation:

First, let us obtain the percentage of sulphur in both compounds. This is illustrated below:

For sodium sulphide (Na₂S):

Molar Mass of Na₂S = (23x2) + 32 = 46 + 32 = 78g/mol

Percentage of sulphur in Na₂S is given by:

32/78 x 100 = 41%

For zinc sulphide (ZnS):

Molar Mass of ZnS = 65.4 + 32 = 97.4g/mol

Percentage of sulphur in ZnS is given by:

32/97.4 x 100 = 33%

From the results obtained sulphur has the highest percentage by mass in sodium sulphide.