Sebanyak 20 gram Kristal NaOH ( Mr = 40 ) dilarutkan dalam 100 gram air, jika NaOH mengion sempurna, hitunglah fraksi mol total ion-ion ( fraksi mol Na+ ditambah fraksi mol OH- dalam larutan ). (Ar H = 1 ; Na = 23 ; O = 16)

bantu ya :)

1

Jawabanmu

2014-07-03T09:25:16+07:00
NNaOH = 20/40 = 1/2 = 0.5 mol
nH₂O    = 100/18 = 5.56 mol
\frac{1/2}{40} = \frac{n}{23}    -> nNa⁺ = 23/80 = 0.29 mol

\frac{1/2}{40} = \frac{n}{17}    -> nOH⁻ = 17/80 = 0.21mol

\frac{100/18}{18} = \frac{n}{17}  -> nOH⁻ = 5.24 mol

x_Na^+= \frac{nNa^+}{nNaOH} = 0.29/0.5 = 0.58

x_OH^-= \frac{nOH^-}{nNaOH+nH_2O} = \frac{0.21+5.24}{5.56+0.5} [/tex] = 5.45/6.06 = 0.899




3 1 3