Question

La ex 3 și 4. Am nevoie in 10 min

Answer 1

ms = 100g 
C=  16,072%
ro = 1,11g/cm3

Vf = 164cm3
Cf = 1M

ro=ms/Vs => Vs= ms/ro = 100/1,11 = 90,09cm3 solutie acid

a. VH2O adaugat = Vf-Vsol acid = 164-90,09 = 73,9 cm3

m H2O = 73,9g 

b. C=md/ms*100 => md=C*ms/100 = 16,072*100/100 = 16,072g acid

Cmf = md/M*Vsf => M = md/Cm*Vsf = 16,072/1*0,164 = 98g/mol  (H2SO4 - acid sulfuric)

c. C = 5*10^(-1) M = 0,5 M

V NaOH = ?

n H2SO4 = 16,072/98 = 0,164 moli H2SO4

H2SO4 + 2NaOH ---> Na2SO4 + 2H2O

n H2SO4 = 2nNaOH = 2*0,164 = 0,328 moli 

C = n/Vs => Vs= n/C = 0,328/0,5 = 0,656 L = 656 cm3 sol. NaOH

4. C1= 63% H2SO4
ro1 = 1,53g/cm3
Vs1 = 2L = 2000mL sau cm3

Vs2 ad = 3L 
C2 = 17,2 %
ro2 = 1,14 g/cm3

Cf  = ?

ro1 = ms1/Vs1 => ms = ro1*Vs1 = 1,53*2000 = 3060g sol H2SO4

C1=md1/ms1*100 => md1 = C1*ms1/100 = 63*3060/100 = 1927,8g H2SO4

ro2 = ms2/Vs2 => ms2=ro2*Vs2 = 1,14*3000 = 3420g sol H2SO4

C2=md2/ms2*100 => md2=C2*ms2/100 = 17,2*3420/100 = 588,24g H2SO4

mdf = md1+md2 = 1927,8+588,24 = 2516,04g
msf = ms1+ms2 = 3420+3060 = 6480g sol.

Cf = mdf/msf*100 = 2516.04/6480*100 = Calculeaza !!!

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