Question

URGENT PANA VINERI DAU COROANA!!!
1)Cate grame de apa si cate grame de sare sunt necesare pt a obtine 10kg solutie de c%=1,5%?
2) Ce cantitate de HCl se gasesc in 200kg solutie de concentratie 15%?
3)Se dizolva 4moli HCl in 40 moli apa. ce concentratie procentuala are solutia obtinuta?
4)Det molaritatea urmatoaelor solutii:
a)3,65gHCl dizolvat in 4L solutie
b)HNO3 30%( cu densitatea 1,184 g/cm³

Answer 1

m(sarii)= 10kg*1,5%:100%=0.15kg=150g
m(H2O)=10kg-0,15kg=9,85kg=9850g
2.m(HCl)=200kg*15% /100%=30kg
3.m(HCl)=4mol*36,5g/mol=146g
m(H2O)= 40mol *18g/mol=720g
m(sol)=146g+720g=866g
%c=146g / 866g *100%=16,85%
4.a. M=3,65g / 36,5g/mol *4l =0,025mol/l, M este molaritatea sau concentratia molara
b. M= 10*1,184g/cm³*30% / 63g/mol=5,638 mol/cm³=0,005638mol/l