1. Calculati volumul solutiei de c% = 28% care se obtine prin dizolvarea a 28 g acid acetic in apa, stiind ca ro = 1,1 g/cm3.
stim ca c% = mdx100/ms
md = 28 g, c% = 28%
=> ms = 28x100/28 = 100 g sol. acid acetic
stim ca ro = ms/Vs
=> Vs = ms/ro = 100/1,1 = 91 cm3 (rotunjit)
2. Determinati volumul de apa distilata (ro = 1,0 g/cm3) necesar obtinerii 200 g solutie de acid acetic cu c% = 28%.
stim ca c% = mdx100/ms
si ca ms = md+m.apa
=> md = msxc%/100
= 200x28/100 = 56 g ac. acetic
=> ma.apa = ms-md = 200-56 = 144 g apa
ro = m/V => V = m/ro
= 144/1 = 144 mL apa
3. Calculati volumul solutiei de Cm = 2 M care se obtine prin dizolvarea a 2 moli acid acetic in apa.
stim ca Cm = nr.moli(n)/Vs
=> Vs = n/Cm = 2/2 = 1 L = 1000 mL sol. acid acetic
