LAMPIRAN B

PERHITUNGAN

B.1 Pembuatan Sabun

B.1.1 Massa Sabun Teori

Perbandingan mol minyak : air : NaOH = 1 : 8 : 4

Massa minyak = 50 gram

Mr. minyak = 200,3 gram/mol (Ayu, 2010)

Mr. air = 18 gram/mol

Mr. NaOH = 40 gram/mol

mol minyak = gram minyakMr minyak

= 50 gram200,3 gram/mol

= 0,249 mol

mol NaOH = 4 x mol minyak = 4 x 0,249 mol = 0,996 mol

mol air = 8 x mol NaOH = 8 x 0,249 mol = 1,992 mol

massa air = mol air x Mr air

= 1,992 mol x 18 gram/mol

= 35,856 gram

Massa NaOH = mol NaOH x Mr NaOH

= 0,996 mol x 40 gram/mol

= 39,84 gram

Massa sabun secara teori = massa minyak + massa air + massa NaOH

= (50 + 35,896 + 39,84) gram

= 125,696 gram

B.1.2 Massa Sabun Praktek

Massa sabun secara praktek = 124,96 gram

B.1.3 Penentuan % Ralat

% Ralat= |massa teori-massa praktekmassa teori |x 100 %

= |125,696 – 124,96125,696 |x 100 %

= 0,58 %

B.2 Perhitungan Analisa Sabun

% Alkali Bebas=V titran x N titran x BM prakteks

massasampel x 1000x 100 %

= 50ml x 0,1N x 40

5gram x1000x 100 %

= 8 %