Question

1. un amestec echimolecular de acid azotic si apa cantareste 810g. Masa acidului azotic din amestec este:
a) 630
b) 180
c) 405
d)315
e)500

Answer 1

MHNO3=63g/mol
MH2O=18g/mol

x=y

63x+18y=810g

81x=810==>x=10 moli

n=m/M==>m=n*M=10*63=630g HNO3