<p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Kali ini kita akan membahas materi kimia tentang molaritas, molalitas, dan fraksi mol. Yuk, kita bahas sama-sama penjelasannya.</span></span></span></p> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Sebelum memahami molaritas, molalitas, dan fraksi mol, kalian harus memahami dulu mol (n) karena ini berhubungan dengan materi yang kita bahas.</span></span></span></p> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Rumus mol :</span></span></span></p> <table> <tbody> <tr> <td style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'><img alt='' src='https://i2.wp.com/rumushitung.com/wp-content/uploads/2020/11/CodeCogsEqn-2.png?resize=117%2C59&ssl=1' style='height:59px; width:117px' /></span></span></span></td> </tr> </tbody> </table> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Keterangan :</span></span></span></p> <ul> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>n = mol zat (mol)</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>gr = massa zat (gram)</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Mr = massa molekul relatif zat (gr/mol)</span></span></span></li> </ul> <h2 style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'><strong>Molaritas</strong> <strong>(M)</strong></span></span></span></h2> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Molaritas adalah besaran yang menyatakan jumlah mol zat terlarut yang dibagi tiap satuan volume larutan. Molaritas biasa disingkat <strong>M </strong>yang bisa digunakan untuk satuan molaritas atau bisa juga <strong>mol/liter</strong> satuan molaritasnya. Terdapat rumus molaritas sebagai berikut :</span></span></span></p> <table> <tbody> <tr> <td style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'><img alt='' src='https://i0.wp.com/rumushitung.com/wp-content/uploads/2020/11/CodeCogsEqn-1.png?resize=108%2C59&ssl=1' style='height:59px; width:108px' /></span></span></span></td> </tr> </tbody> </table> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Rumus Molaritas</span></span></span></p> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Keterangan :</span></span></span></p> <ul> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>M = molaritas zat (mol/L)</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>n = mol zat (mol)</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>V = volume larutan (ml)</span></span></span></li> </ul> <h2 style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'><strong>Molalitas (m)</strong></span></span></span></h2> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Molalitas adalah besaran yang menyatakan jumlah mol zat terlarut yang dibagi tiap satuan massa pelarut. Molalitas bisa disingkat <strong>m</strong> yang bisa digunakan untuk satuan molalitas atau <strong>mol/kg</strong> satuan molalitas. Rumus molalitas sebagai berikut :</span></span></span></p> <table> <tbody> <tr> <td style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'><img alt='' src='https://i1.wp.com/rumushitung.com/wp-content/uploads/2020/11/CodeCogsEqn-7.png?resize=171%2C67&ssl=1' style='height:67px; width:171px' /></span></span></span></td> </tr> </tbody> </table> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Rumus Molalitas</span></span></span></p> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Keterangan :</span></span></span></p> <ul> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>m = molalitas zat (mol/kg)</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>n = mol zat (mol)</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>P = massa zat pelarut (gram)</span></span></span></li> </ul> <h2 style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'><strong>Fraksi Mol</strong></span></span></span></h2> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Fraksi mol adalah jumlah mol suatu komponen larutan dan jumlah mol seluruh komponen larutan yang mengalami perbandingan. Fraksi mol tidak mempunyai satuan karena fraksi mol hanya membandingkan jumlah mol. Fraksi mol bisa dirumuskan sebagai berikut :</span></span></span></p> <table> <tbody> <tr> <td style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'><img alt='' src='https://i0.wp.com/rumushitung.com/wp-content/uploads/2020/11/CodeCogsEqn-4.png?resize=131%2C21&ssl=1' style='height:21px; width:131px' /></span></span></span></td> </tr> <tr> <td style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'><img alt='' src='https://i2.wp.com/rumushitung.com/wp-content/uploads/2020/11/CodeCogsEqn-6.png?resize=152%2C48&ssl=1' style='height:48px; width:152px' /></span></span></span></td> </tr> <tr> <td style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'><img alt='' src='https://i2.wp.com/rumushitung.com/wp-content/uploads/2020/11/CodeCogsEqn-5.png?resize=153%2C48&ssl=1' style='height:48px; width:153px' /></span></span></span></td> </tr> </tbody> </table> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Rumus Fraksi Mol</span></span></span></p> <h2 style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'><strong>Contoh soal :</strong></span></span></span></h2> <h5 style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'><strong>Contoh Menghitung Mol</strong></span></span></span></h5> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Hitung jumlah mol NaOH dengan massa 0,02 kg dan Massa relatif dari NaOH 40 gr/mol.</span></span></span></p> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Penyelesaian :</span></span></span></p> <ul> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>gr = 0,02 kg = 20 gram</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Mr NaOH = 40 gr/mol</span></span></span></li> </ul> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>n = gr / Mr</span></span></span></p> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>n = 20 / 40 = 1/2 = 0,5 mol</span></span></span></p> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Jadi, jumlah mol NaOH adalah 0,5 mol</span></span></span></p> <h5 style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'><strong>Contoh Menghitung Molaritas</strong></span></span></span></h5> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Hitung molaritas larutan pada NaOH dengan melarutkan 8 gram NaOH dalam 200 ml larutan ! (Ar Na = 23, Ar H = 1, Ar O = 16)</span></span></span></p> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Penyelesaian :</span></span></span></p> <ul> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>gr = 8 gram</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>V = 200 ml = 0,2 L</span></span></span></li> </ul> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Menentukan Mr NaOH :</span></span></span></p> <ul> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Mr = 1Ar Na + 1Ar O + 1Ar H</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Mr = 23 + 16 + 1</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Mr = 40 gr/mol</span></span></span></li> </ul> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Menentukan n (mol) NaOH :</span></span></span></p> <ul> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>n = gr / Mr</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>n = 8 / 40</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>n = 1 / 5</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>n = 0,2 mol</span></span></span></li> </ul> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Menentukan molaritas (M) NaOH :</span></span></span></p> <ul> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>M = n / V</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>M = 0,2 / 0,2</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>M = 1 M atau 1 mol/liter</span></span></span></li> </ul> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Jadi, molaritas dari NaOH adalah 1 M</span></span></span></p> <h5 style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'><strong>Contoh Menghitung Molalitas</strong></span></span></span></h5> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Hitunglah molalitas H2SO4 dengan 98 gram dilarutkan dalam 1 kg air ! (Mr H2SO4 = 98 gr/mol)</span></span></span></p> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Penyelesaian :</span></span></span></p> <ul> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>gr = 98 gram</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>P = 1 kg =1000 gram</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Mr = 98 gr/mol</span></span></span></li> </ul> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Menentukan mol :</span></span></span></p> <ul> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>n = gr / Mr</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>n = 98 / 98</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>n = 1 mol</span></span></span></li> </ul> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Menentukan molalitas H2SO4 :</span></span></span></p> <ul> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>m = n . 1000 / P</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>m = 1 . 1000 / 1000</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>m = 1 m atau 1 mol/kg</span></span></span></li> </ul> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Jadi molalitasnya adalah 1 mol/kg</span></span></span></p> <h5 style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'><strong>Contoh Menghitung Fraksi Mol</strong></span></span></span></h5> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Diketahui larutan yang terdiri dari 2 mol zat A, 4 mol zat B, dan 2 mol zat C. Hitung fraksi mol pada masing – masing mol zat tersebut !</span></span></span></p> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Penyelesaian :</span></span></span></p> <ul> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>n<sub>A</sub> = 2 mol</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>n<sub>B</sub> = 4 mol</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>n<sub>C</sub> = 2 mol</span></span></span></li> </ul> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Menentukan fraksi mol :</span></span></span></p> <ul> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>X<sub>A</sub> = n<sub>A</sub> / (n<sub>A</sub> + n<sub>B</sub> + n<sub>C</sub>)</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>X<sub>A</sub> = 2 / (2 + 4 + 2)</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>X<sub>A</sub> = 2 / 8</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>X<sub>A</sub> = 1 / 4</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>X<sub>A</sub> = 0,25</span></span></span></li> </ul> <ul> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>X<sub>B</sub> = n<sub>B</sub> / (n<sub>A</sub> + n<sub>B</sub> + n<sub>C</sub>)</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>X<sub>B</sub> = 4 / (2 + 4 + 2)</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>X<sub>B</sub> = 4 / 8</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>X<sub>B</sub> = 1 / 2</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>X<sub>B</sub> = 0,5</span></span></span></li> </ul> <ul> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>X<sub>C</sub> = n<sub>C</sub> / (n<sub>A</sub> + n<sub>B</sub> + n<sub>C</sub>)</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>X<sub>C</sub> = 2 / (2 + 4 + 2)</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>X<sub>C</sub> = 2 / 8</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>X<sub>C</sub> = 1 / 4</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>X<sub>C</sub> = 0,25</span></span></span></li> </ul> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Jadi, fraksi mol masing – masing adalah :</span></span></span></p> <ul> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>X<sub>A</sub> = 0,25</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>X<sub>B</sub> = 0,5</span></span></span></li> <li style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>X<sub>C</sub> = 0,25</span></span></span></li> </ul> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Dari ketiga fraksi mol di atas, jika dijumlahkan harus menghasilkan 1 sesuai rumus :</span></span></span></p> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>X<sub>A</sub> + X<sub>B</sub> + X<sub>C</sub> = 1</span></span></span></p> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>0,25 + 0,5 + 0,25 = 1</span></span></span></p> <p style='text-align: justify;'><span style='font-family:Arial,Helvetica,sans-serif'><span style='font-size:14px'><span style='color:#000000'>Demikian pembahasan dari kami, semoga bermanfaat dan menambah wawasan serta pengetahuan kalian. Sekian terima kasih.</span></span></span></p>