☰ Mundarija · Kimyo (Umumiy kimyo)

Mendeleyev–Klapeyron tenglamasi

Darslar 8 · 1 ta dars · S. Masharipov, A. Mutalibov, E. Murodov, H. Islomova. Umumiy kimyo 11-sinf, 1-nashr. G‘afur G‘ulom nomidagi nashriyot-matbaa ijodiy uyi, Toshkent, 2018
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Mendeleyev–Klapeyron tenglamasi

Darslik: 45–50-betlar
MaqsadNormal sharoit tushunchasini va Mendeleyev–Klapeyron tenglamasini PV = nRT tushuntirish hamda har qanday sharoitdagi gazning hajmi, bosimi, harorati, massasi va molyar massasini hisoblash.
Yangi so‘zlar
normal sharoit · normal conditionsideal gaz · ideal gasuniversal gaz doimiysi · universal gas constantKelvin shkalasi · Kelvin scale
Tushuntirish

Normal sharoit: harorat 0 °C (273 K) va bosim 101,325 kPa (1 atm = 760 mm sim. ust.). Reaksiyalar har doim ham shu sharoitda o‘tmaydi, shuning uchun ideal gaz holat tenglamasi — Mendeleyev–Klapeyron tenglamasi qo‘llaniladi: PV = nRT. Bunda P — bosim, V — hajm, n — modda miqdori (mol), T — harorat Kelvinda, R — universal gaz doimiysi. Bosim kPa, hajm litrda olinsa R = 8,31 kPa·l/(mol·K); bosim atmosferada olinsa R ≈ 0,082 atm·l/(mol·K). Selsiydan Kelvinga o‘tish: T = t + 273. n = m/M ekanini hisobga olib tenglama PV = (m/M)·RT, ya’ni M = mRT/(PV) ko‘rinishida ham yoziladi; undan gazning molyar massasini topib, noma’lum gazni aniqlash mumkin. Qat’iy temperaturada bosim ikki marta oshsa, hajm ikki marta kamayadi; tenglama normal sharoit uchun ham to‘g‘ri natija beradi: 1 mol uchun V = 8,31·273/101,325 ≈ 22,4 l.

Namunalar
2 mol gaz 27 °C da va 249,3 kPa bosimda qancha hajm egallaydi? T = 27 + 273 = 300 K; V = nRT/P = 2·8,31·300/249,3 = 20 l.
27 °C va 124,65 kPa da 1 l hajmli idishdagi gazning massasi 1,6 g. M = mRT/(PV) = 1,6·8,31·300/(124,65·1) = 32 g/mol — bu kislorod bo‘lishi mumkin.
Sinfda faoliyat

Hisoblash ustaxonasi: bir xil gaz (1 mol) uchun normal sharoitda hajmni, so‘ng 27 °C va 100 kPa da hajmni tenglama bilan hisoblang; natijalarni solishtirib, harorat va bosim hajmga qanday ta’sir qilishini muhokama qiling.

Mashq
1
1 mol gaz 27 °C da 24,93 l hajmni egallaydi. Uning bosimi necha kPa?
2
2 mol gaz 300 kPa bosimda 16,62 l hajmni egallaydi. Harorat necha °C?
3
83,1 kPa bosimda va 27 °C da 15 l CO₂ ning (M = 44 g/mol) massasi necha gramm?
4
Nima uchun PV = nRT da haroratni Kelvinda olish shart?