Pertanyaan

Hitunglah molalitas dan fraksi mol larutan NaOH dalam air yang kadarnya 40%. (M r NaOH = 40).

Hitunglah molalitas dan fraksi mol larutan NaOH dalam air yang kadarnya 40%. (M_r NaOH = 40). $\;$

N. Puspita

Master Teacher

Jawaban terverifikasi

Pembahasan

KadarNaOH sebesar 40%. Misalnya massa larutan NaOH sebesar 100 gram, maka: Jadi, molalitas larutan sebesar 16,67 m, fraksi mol NaOH sebesar 0,231, dan fraksi mol air sebesar 0,769.

Kadar NaOH sebesar 40%. Misalnya massa larutan NaOH sebesar 100 gram, maka:

table attributes columnalign right center left columnspacing 0px end attributes row cell m space Na O H end cell equals cell 40 percent sign cross times 100 space gram end cell row blank equals cell 40 space gram end cell end table

table attributes columnalign right center left columnspacing 0px end attributes row cell m space air end cell equals cell 100 space gram minus sign 40 space gram end cell row blank equals cell 60 space gram end cell end table

$table attributes columnalign right center left columnspacing 0px end attributes row Molalitas equals cell fraction numerator m space Na O H over denominator M subscript r end fraction cross times fraction numerator 1.000 over denominator m space air end fraction end cell row blank equals cell fraction numerator 40 over denominator left parenthesis 1 cross times A subscript r space Na right parenthesis plus left parenthesis 1 cross times A subscript r space O right parenthesis plus left parenthesis 1 cross times A subscript r space H right parenthesis end fraction cross times fraction numerator 1.000 over denominator 60 end fraction end cell row blank equals cell fraction numerator 40 over denominator 23 plus 16 plus 1 end fraction cross times fraction numerator 1.000 over denominator 60 end fraction end cell row blank equals cell 16 comma 67 space m end cell end table$

$table attributes columnalign right center left columnspacing 0px end attributes row cell X space Na O H end cell equals cell fraction numerator n space Na O H over denominator n space Na O H and n space air end fraction end cell row blank equals cell fraction numerator begin display style bevelled 40 over 40 end style over denominator begin display style bevelled 40 over 40 end style plus begin display style bevelled 60 over 18 end style end fraction end cell row blank equals cell 0 comma 231 end cell end table$

table attributes columnalign right center left columnspacing 0px end attributes row cell X space air end cell equals cell 1 minus sign X space Na O H end cell row blank equals cell 1 minus sign 0 comma 231 end cell row blank equals cell 0 comma 769 end cell end table

Jadi, molalitas larutan sebesar 16,67 m, fraksi mol NaOH sebesar 0,231, dan fraksi mol air sebesar 0,769.

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