● Entalpi pelarutan NaOH adalah...
Jawaban:
B. -33,6 kJ/mol
Penjelasan:
Diket:
m NaOH = 0,5 gr
Mr = 40 gr/mol
V air = 50 ml
∆T = 28-26 = 2°C
c = 4,2 J/g°C
Ditanya: ∆H pelarutan NaOH?
Jawab:
1. Mencari kalor
rho air = 1gr/ml
rho = m/v
1 gr/ml= m/50ml
m = 50 gr
q = m x c x ∆T
q = 50 gr x 4,2 J/g°C x 2°C
q = 420 J
2. Menentukan mol kristal NaOH
n = m/Mr
n = 0,5 gr/40 gr/mol
n = 0,0125 mol
3. Menentukan ∆H pelarutan NaOH
∆H = - q/mol
∆H = - 420J/0,0125 mol
∆H = - 33600 J/mol
∆H = - 33,6 kJ/mol
