Sebanyak 3,12 gram basa lemah dilarutkan ke dalam...

Sebanyak 3,12 gram basa lemah $begin mathsize 14px style italic L open parentheses O H close parentheses subscript 3 end style$ dilarutkan ke dalam 200 mL larutan $begin mathsize 14px style italic L Cl subscript 3 end style$ 0,2 M menghasilkan larutan penyangga dengan pH = 9. Jika $begin mathsize 14px style K subscript b space italic L open parentheses O H close parentheses subscript 3 equals 10 to the power of negative sign 5 end exponent end style$ , massa atom relatif unsur L adalah .... ( $begin mathsize 14px style A subscript r colon space H equals 1 space g space mol to the power of negative sign 1 end exponent space dan space O equals 16 space g space mol to the power of negative sign 1 end exponent end style$ ) $space$

Jawaban:

Massa atom relatif L dapat dicari dengan mencari mol basa lemah dengan larutan penyangga basa dengan pH=9.

$begin mathsize 14px style pH equals 9 pOH equals 14 minus sign 9 equals 5 open square brackets O H to the power of minus sign close square brackets equals 10 to the power of negative sign 5 end exponent open square brackets O H to the power of minus sign close square brackets double bond K subscript b cross times fraction numerator mol space basa over denominator mol space garam end fraction 10 to the power of negative sign 5 end exponent equals 10 to the power of negative sign 5 end exponent cross times fraction numerator mol space basa over denominator 0 comma 2 space M space. space 200 cross times 10 to the power of negative sign 3 end exponent space L space end fraction mol space basa equals 0 comma 2 space M point 200 cross times 10 to the power of negative sign 3 end exponent L mol space basa equals 0 comma 04 space mol end style$

Setelah mol basa diketahui, massa atom relatif L dapat diketahui melalui cara berikut ini;

$begin mathsize 14px style Mol space italic L open parentheses O H close parentheses subscript 3 equals fraction numerator massa over denominator Mr end fraction Mr space italic L open parentheses O H close parentheses subscript 3 equals fraction numerator massa over denominator mol end fraction Ar space L plus left parenthesis 3 cross times left parenthesis Ar space O plus space Ar space H right parenthesis right parenthesis equals massa over mol Ar space L plus left parenthesis 3 cross times left parenthesis 16 plus 1 right parenthesis right parenthesis equals fraction numerator 3 comma 12 space gram over denominator 0 comma 04 space mol end fraction Ar space L plus 51 equals 78 space begin inline style bevelled g over mol end style Ar space L equals 78 minus sign 51 space begin inline style bevelled g over mol end style Ar space L equals 27 space begin inline style bevelled g over mol end style end style$

Jadi, massa atom relatif (Ar) L adalah 27 g/mol. $space$

Ruangguru

RUANGGURU HQ

Jl. Dr. Saharjo No.161, Manggarai Selatan, Tebet, Kota Jakarta Selatan, Daerah Khusus Ibukota Jakarta 12860

Coba GRATIS Aplikasi Ruangguru

Download di Google Play

Download di Appstore

Produk Ruangguru

Produk Lainnya

Bantuan & Panduan

Hubungi Kami

081578200000

[email protected]

02140008000

Ikuti Kami

Instagram

Facebook

Twitter

Youtube