Piv txwv ntawm Cov Lus Nug Sib Tham txog Osmotic Siab ntawm Cov Tshuaj
Pendahuluuan
Lub siab osmotic yog ib qho tseem ceeb hauv chemistry thiab biology. Nws yog lub siab uas yuav tsum tau los tiv thaiv cov dej ntws hla lub semipermeable membrane los ntawm cov tshuaj uas muaj concentration tsawg mus rau cov tshuaj uas muaj concentration siab. Kev nkag siab txog lub siab osmotic yog qhov tseem ceeb hauv ntau yam kev siv, xws li cov txheej txheem biological hauv cov cell, kev kho dej, thiab kev tsim tshuaj. Txhawm rau piav qhia lub tswv yim no kom meej dua, peb yuav tham txog ntau qhov piv txwv ntawm cov teeb meem thiab cov kev daws teeb meem ntsig txog lub siab osmotic ntawm cov tshuaj.
Lo Lus Nug 1: Xam Osmotic Siab ntawm Cov Tshuaj Qab Zib
Lo lus nug:
Ob grams ntawm sucrose (C12H22O11) raug yaj rau hauv dej kom ua tau 500 mL. Lub zog osmotic ntawm cov tshuaj no ntawm 25°C yog dab tsi? (Siv R = 0.0821 L·atm·K^-1·mol^-1 thiab qhov hnyav molar ntawm sucrose = 342 g/mol).
Kev Sib Tham:
1. Xam cov molarity ntawm cov tshuaj:
Molarity (M) = \( \dfrac{\text{Tus lej ntawm moles ntawm solute}}{\text{Volume ntawm cov kua hauv litres}} \)
Tus naj npawb ntawm cov moles ntawm sucrose = \( \dfrac{2 \text{ g}}{342 \text{ g/mol}} \) = 0.00585 mol
Qhov ntim ntawm cov tshuaj = 500 mL = 0.5 L
Molarity (M) = \( \dfrac{0.00585 mol}{0.5 L}} \) = 0.0117 M
2. Xam qhov siab osmotic:
Lub zog osmotic (π) = MRT
Qhov twg:
M = 0.0117 mol/L
R = 0.0821 L atm K^-1 mol^-1
T = 25°C = 298 K (vim tias qhov kub yuav tsum yog hauv Kelvin)
π = (0.0117 mol/L)(0.0821 L·atm·K^-1·mol^-1)(298 K)
π = 0.286 atm
Yog li, lub osmotic siab ntawm cov kua sucrose yog 0.286 atm.
Lo lus nug 2: Osmotic Siab ntawm Electrolyte Solution
Lo lus nug:
Lub zog osmotic ntawm NaCl kua nrog qhov concentration ntawm 0.2 M ntawm qhov kub ntawm 27 ° C yog dab tsi? (Nws paub tias NaCl yog ib qho electrolyte uas dissociates tag nrho rau hauv Na + thiab Cl- nrog R = 0.0821 L · atm · K ^ - 1 · mol ^ - 1)
Kev Sib Tham:
1. Xam qhov degree ntawm kev sib cais:
NaCl → Na+ + Cl-
Vim tias NaCl raug sib cais tag nrho, tag nrho cov khoom me me hauv cov kua yog ob npaug ntawm moles ntawm NaCl.
Tag nrho cov khoom me me = 2 × tus naj npawb ntawm moles ntawm NaCl
2. Xam qhov siab osmotic:
Osmotic siab (π) = iMRT
Qhov twg:
i = 2 (vim muaj 2 hom ions, Na+ thiab Cl-)
M = 0.2 mol/L
R = 0.0821 L atm K^-1 mol^-1
T = 27°C = 300 K
π = (2)(0.2 mol/L)(0.0821 L·atm·K^-1·mol^-1)(300 K)
π = 9.852 atm
Yog li, qhov osmotic siab ntawm 0.2 M NaCl kua ntawm 27 ° C yog 9.852 atm.
Lo lus nug 3: Osmotic Siab hauv Cov Kua Qab Zib thiab Fructose
Lo lus nug:
Ib qho kev daws teeb meem yog ua los ntawm kev yaj 1 mole ntawm qabzib (C6H12O6) thiab 1 mole ntawm fructose (C6H12O6) rau hauv 1 liter dej. Lub siab osmotic ntawm cov tshuaj ntawm 37°C yog dab tsi? (Siv R = 0.0821 L atm K^-1 mol^-1)
Kev Sib Tham:
1. Xam tag nrho cov moles:
Tag nrho cov moles = 1 mole ntawm glucose + 1 mole ntawm fructose = 2 moles
2. Xam qhov siab osmotic:
Lub zog osmotic (π) = MRT
Qhov twg:
M = 2 mol/L (vim tias muaj tag nrho 2 moles hauv 1 liter dej)
R = 0.0821 L atm K^-1 mol^-1
T = 37°C = 310 K
π = (2 mol/L)(0.0821 L·atm·K^-1·mol^-1)(310 K)
π = 50.942 atm
Yog li, lub siab osmotic ntawm cov tshuaj uas muaj 1 mole ntawm qabzib thiab 1 mole ntawm fructose hauv 1 liter dej ntawm 37 ° C yog 50.942 atm.
Lo lus nug 4: Kev sib xyaw ntawm ob yam khoom uas tsis yog electrolyte
Lo lus nug:
Lub siab osmotic ntawm qhov sib tov uas muaj 0.5 mol ntawm urea (CO(NH2)2) thiab 0.5 mol ntawm ethanol (C2H5OH) hauv 1 liter dej ntawm 20°C yog dab tsi? (R = 0.0821 L·atm·K^-1·mol^-1)
Kev Sib Tham:
1. Xam tag nrho cov moles hauv cov tshuaj:
Tag nrho cov moles = 0.5 mol urea + 0.5 mol ethanol = 1 mol
2. Xam qhov siab osmotic:
Lub zog osmotic (π) = MRT
Qhov twg:
M = 1 mol/L (vim tias muaj tag nrho 1 moles hauv 1 liter dej)
R = 0.0821 L atm K^-1 mol^-1
T = 20°C = 293 K
π = (1 mol/L)(0.0821 L·atm·K^-1·mol^-1)(293 K)
π = 24.0633 atm
Yog li, lub siab osmotic ntawm qhov sib tov uas muaj 0.5 mol ntawm urea thiab 0.5 mol ntawm ethanol hauv 1 liter dej ntawm 20 ° C yog 24.0633 atm.
Xaus
Los ntawm qhov teeb meem piv txwv saum toj no, peb tuaj yeem nkag siab yuav ua li cas xam lub zog osmotic nyob rau hauv ntau yam xwm txheej. Lub zog osmotic raug cuam tshuam los ntawm cov yam xws li kev sib xyaw ua ke ntawm cov tshuaj, hom solute (electrolyte lossis non-electrolyte), thiab kub. Kev tshuaj xyuas lej tom qab lub zog osmotic vam khom cov hauv paus ntsiab lus uas tau teev tseg los ntawm txoj cai roj zoo tagnrho. Nrog kev nkag siab zoo txog lub tswv yim no, peb tuaj yeem siv nws rau ntau yam xwm txheej hauv chemistry thiab biology.
