Page 249 - Chemistry eBook

Percent Composition Example
What is the percent composition of H in (NH4)2SO4?
1. Percent composition of H: 1 x 8 = 8 (atomic mass × the product of the subscripts inside and
outside the parentheses)
2. Percent composition of the entire molecule:
N: 14 x 2 = 28
H: 1 x 8 = 8 (atomic mass × the product of the subscripts inside and outside the parentheses) S: 32
O: 16 x 4 = 64 (atomic mass × subscript)
28 + 8 + 32 + 64 = 132
3. 8 × 100 132
4. 0.0606 × 100 =6.0%
The percent composition of H in (NH4)2SO4 is 6.0%.
UNIT 6: MATH IN CHEMISTRY © 248