LAMPIRAN B

PERHITUNGAN

LB.1 Pembuatan Sabun

LB.1.1 Massa Sabun Teori

Perbandingan mol minyak : air : NaOH = 1 : 6 : 2

Massa minyak = 50 gram

Mr minyak = 256 gram/mol

Mr air = 18 gram/mol

Mr NaOH = 40 gram/mol

mol minyak = Massa minyakMr minyak = 50 gram

256 gram/mol = 0,1953 mol

mol air = 6 x mol minyak = 6 x 0,1953 mol = 1,1718 mol

mol NaOH = 2 x mol minyak = 2 x 0,1953 = 0,3906 mol

massa air = mol air x Mr air

= 1,1718 mol x 18 gram/mol

= 21,09 gram

Massa NaOH = mol NaOH x Mr NaOH

= 0,3906 mol x 40 gram/mol

= 15,624 gram

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

= 50 gram + 21,09 gram + 15,624 gram

= 86,714 gram

LB.1.2 Massa Sabun Praktek

Massa sabun secara praktek = 84,26 gram

LB.1.3 Penentuan % Ralat

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

= |86,714 gram-84,26 gram86,714 gram | x 100%

= 2,82 %

LB.2 Perhitungan Analisa Sabun

%Alkali Bebas =Vtitran x Ntitran x BMpraktek

massa sampel x 1000

= 4 ml x 0,1 N x 40 gram/mol 5 gram x 1000

= 0,32 %