Jika Ar C = 12 ; O = 16 ; N = 14 ; H = 1. Tentukan kemurnian pupuk urea tersebut!
Penyelesaian soal!
Diketahui:
m Urea = 50 gram
m N = 21 gram
Ar C = 12
Ar O = 16
Ar N = 14
Ar H = 1
Ditanya : kemurnian pupuk urea
Jawab:
% N dalam urea = 2 × Ar N × 100%
Mr CO(NH₂)₂
= 2 × 14 × 100%
60
= 47%
m N dalam urea = 47 × 50 gram
100
= 23,5 gram
Kemurnian urea = 21 × 100%
23,5
= 89,37%