Sagot :
SOLUCIÓN :
1) g sto= ? K2Cr2O7 PmK2Cr2O7 = 294 g/mol
sol = 250 ml sol
M = 2.16 M
250mlso*1Lt sol/ 1000 ml*2.16 moles sto/1 lt sol*294 g stoK2Cr2O7/1molsto=
= 158.76 g sto K2Cr2O7.
2) M =?
sol = 85ml * 1 Lt sol / 1000 ml sol= 0.085 Lts sol
sto = 1.77 g etanol ( C2H5OH) PmC2H5OH= 46 g/mol
1.77 g sto etanol* 1 mol sto/46 g sto = 0.0384 mol sto etanol
M = 0.0384 mol sto/0.085 Lts sol
M =0.45 mol/lts = 0.45 M.
3) sto = 3.81 g Glucosa
sol =? ml
M = 2.53 M
Pm glucosa = 180.155 g/mol
3.81 gsto* 1 molsto/180.155 gsto* 1 lt sol/ 2.53 mol sto* 1000 ml sol/ 1 lt sol=
= 8.35 ml sol Glucosa .
4) a ) 1 lt sol HCl/ 0.1 mol HCl*0.2 mol HCl= 2 Lts sol HCl= 2000 ml HCl
b) 1 lt sol NaOH/0.2 moles NaOH* 0.2 moles NaOH= 1 lts sol NaOH
= 1000 ml sol NaOH
c) 1 lt sol HNO3/0.01 molHNO3*0.2 molHNO3=20 lts HNO3
= 20000 ml HNO3