Tabung elpiji berisi gas metana (gas lain di abaikan). Tekanan dalam tabung 18 bar (1 bar = ... atm), massa gas 3 kg. Tentukan : a. berapa mol gas metana tersebut. b. berapa volume gas jika berada pada suhu 27 derajat Celsius. c. berapa banyak jumlah molekul metana tersebut?

Pertanyaan

Tabung elpiji berisi gas metana $begin mathsize 14px style C H subscript 4 end style$ (gas lain di abaikan). Tekanan dalam tabung 18 bar (1 bar = ... atm), massa gas 3 kg. Tentukan :

a. berapa mol gas metana tersebut.

b. berapa volume gas jika berada pada suhu 27 derajat Celsius.

c. berapa banyak jumlah molekul metana tersebut?

Pembahasan Soal:

Gas metana $begin mathsize 14px style C H subscript 4 end style$ memilki massa = 3 kg.

a. Jumlah mol gas metana.

Hitung massa molar $begin mathsize 14px style C H subscript 4 end style$ .

$begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell M subscript m C H subscript 4 end cell equals cell M subscript r C H subscript 4 end cell row cell M subscript m C H subscript 4 end cell equals cell 1 cross times A subscript r C plus 4 cross times A subscript r H end cell row cell M subscript m C H subscript 4 end cell equals cell 1 cross times 12 plus 4 cross times 1 end cell row cell M subscript m C H subscript 4 end cell equals cell 12 plus 4 end cell row cell M subscript m C H subscript 4 end cell equals cell 16 space g space mol to the power of negative sign 1 end exponent end cell end table end style$

Hitung mol $begin mathsize 14px style C H subscript 4 end style$ (dihitung dengan menggunakan hubungan antara massa zat (m) dan massa molar).

$begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell italic m italic space C H subscript 4 end cell equals cell n cross times M subscript m end cell row cell italic n space C H subscript 4 end cell equals cell m over M subscript m end cell row cell italic n space C H subscript 4 end cell equals cell fraction numerator 3 space kg cross times 1000 space g forward slash kg over denominator 16 space g space mol to the power of negative sign 1 end exponent end fraction end cell row cell italic n space C H subscript 4 end cell equals cell 187 comma 5 space mol end cell end table end style$

b. Penentuan volume gas $begin mathsize 14px style C H subscript 4 end style$ jika berada pada suhu 27 derajat Celsius.

Hitung tekanan gas $begin mathsize 14px style C H subscript 4 end style$ .

$begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell 1 space bar end cell equals cell 0 comma 987 space atm end cell row P equals cell 18 space bar space cross times 0 comma 987 atm space bar to the power of negative sign 1 end exponent end cell row P equals cell 17 comma 77 space atm end cell end table end style$

Konversi suhu dalam satuan suhu mutlak (K)

$begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row T equals cell 27 space degree C plus 273 end cell row T equals cell 300 space K end cell end table end style$

Hitung tekanan gas $begin mathsize 14px style C H subscript 4 end style$ dengan menggunakan persamaan gas ideal.

$begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell P cross times V end cell equals cell n cross times R cross times T end cell row V equals cell fraction numerator n cross times R cross times T over denominator P end fraction end cell row V equals cell fraction numerator 187 comma 5 space mol cross times 0 comma 082 space L space atm space mol to the power of negative sign 1 end exponent space K to the power of negative sign 1 end exponent cross times 300 space K over denominator 17 comma 77 space atm end fraction end cell row V equals cell fraction numerator 4612 comma 5 over denominator 17 comma 77 end fraction L end cell row V equals cell 259 comma 57 space L end cell end table end style$

c. Jumlah molekul metana.

$begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell Jumlah space Partikel space C H subscript 4 end cell equals cell n cross times L end cell row cell Jumlah space Partikel space C H subscript 4 end cell equals cell 187 comma 5 space mol cross times 6 comma 02 cross times 10 to the power of 23 space molekul space mol to the power of negative sign 1 end exponent end cell row cell Jumlah space Partikel space C H subscript 4 end cell equals cell 1 comma 13 cross times 10 to the power of 26 space molekul end cell end table end style$

Jadi, jumlah mol, volume, dan jumlah molekul gas metana adalah 187,5 mol, 259,57 L, dan $begin mathsize 14px style 1 comma 13 cross times 10 to the power of 26 space molekul end style$ .

Pembahasan terverifikasi oleh Roboguru

Terakhir diupdate 14 Maret 2021

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