Van der Walls ke lebitso la setsebi sa fisiks sa Madache, JD van der Waals (1837-1923). Van der Waals Equation of State ke equation ea boemo ba khase, e ts'oanang le Equation ea boemo ba khase e loketseng. Phapang ke hore, Equation ea boemo ba khase e loketseng e ke ke ea fana ka liphetho tse nepahetseng haeba khatello le bongata ba khase ea 'nete li lekana. Athe Van der Waals Equation of State e ka hlahisa liphetho tse nepahetseng haholoanyane.
Boteng ba equation ena bo simoloha ho Van der Waals, ea ileng a hlokomela mefokolo ea equation ea boemo bo loketseng. Waals, fetola equation ea boemo ba khase e loketseng, ka ho eketsa lintlha tse 'maloa tse susumetsang boemo ba khase ea sebele, ha khatello le boima ba khase ea sebele li le kholo.
Kgatelelo ya khase e lekana ka tsela e fapaneng le bophahamo ba modumo. Haeba kgatelelo ya khase e eketseha, bophahamo ba khase bo a fokotseha. Ka lehlakoreng le leng, haeba bophahamo ba khase bo fokotseha, kgatelelo ya khase e a eketseha. Ha bophahamo ba khase bo fokotseha, bongata ba khase bo a eketseha (boima = boima / bophahamo ba modumo). Ho ka thwe kgatelelo e lekana ka ho toba le bongata ba modumo. Haeba kgatelelo ya khase e le kgolo, bongata ba khase le bona bo boholo. Ka lehlakoreng le leng, haeba kgatelelo ya khase e le nyane, bongata ba khase le bona bo bonyenyane. Kgatelelo ya khase le yona e lekana ka ho toba le mocheso. Haeba kgatelelo ya khase e eketseha, mocheso wa khase o a eketseha. Re ka etsa qeto ya hore haeba kgatelelo ya khase e eketseha, mocheso le bongata ba khase, ha bongata ba khase bo fokotseha.
Ha bophahamo ba khase bo fokotseha, sebaka se pakeng tsa limolek'hule sea atamela. Ha sebaka se pakeng tsa limolek'hule se atamela, limolek'hule lia hohelana. Ho tšoana le ha karolo ea tšepe e tlisoa haufi le makenete. Haeba sebaka se pakeng tsa makenete le tšepe se le hole haholo, makenete e ke ke ea hula tšepe. Empa haeba sebaka se pakeng tsa makenete le tšepe se le haufi, tšepe e huloa haufi. Ha limolek'hule li le mothating oa ho thulana, lielektrone tse ka ntle ho molek'hule lia retellana (ho repulsion ea motlakase). Ka lebaka leo, limolek'hule li ke ke tsa khomarelana. Ho tsoa tlhalosong ena e khutšoanyane, ho ka thoe matla a ho hula pakeng tsa limolek'hule a susumetsa boemo ba khase.
Ha kgatello ya kgase e le kgolo ka ho lekaneng, mme bophahamo ba kgase bo ba bonyenyane, sebaka se pakeng tsa dimolek'hule se a atamelana. Hobane dimolek'hule le tsona di na le boholo (bophara ba athomo = 10 -10 m), re boetse re hloka ho nahana ka bophahamo ba dimolek'hule tsena.
Van der Waals e fokotsa equation ea boemo, ho nahanoa ka bophahamo ba limolek'hule le likamano tse hlahang lipakeng tsa limolek'hule. Equation e nkiloeng ke Van der Waals ke phello ea phetoho ea equation e ntle ea boemo ba khase PV = n R T. Van der Waals Equation of State:
P = khatello ea khase (N / m2 = Pa)
V = bophahamo ba khase ( m3 )
R = khase e sa fetoheng ka kakaretso (R = 8.315 J / mol. K = 8315 kJ / kmol. K)
T = mocheso (K)
a = botsitso ba 'mele (boleng bo itšetlehile ka matla a ho hohela pakeng tsa limolek'hule tsa khase)
b = phetoho e sa fetoheng (e emelang bophahamo ba mole e le 'ngoe ea limolek'hule tsa khase)
n = Palo ea li-moles (mol)
bn = kakaretso ea limolek'hule tsa khase
Li-constant a le b li fumanoa ka liteko. Boleng ba kamehla a le b bo itšetlehile ka mofuta oa khase.
n2 / V2 = karolelano ea quadratic ea palo ea li-mole (n) le sekwere sa bophahamo ba khase (V). Boleng ba n2 / V2 ho itshetlehile ka kgatello le boima ba kgase. Haeba kgatello ya kgase (P) e le kgolo, jwale bophahamo ba kgase (V) bo bonyenyane. Ha V e le nyane, e kgolo ke n2 / V2Ha bophahamo ba khase bo le bonyenyane (n2 / V2 e kgolo) sebaka se pakeng tsa dimolek'hule se haufi. Ha sebaka se pakeng tsa dimolek'hule se le haufi, dikamano pakeng tsa dimolek'hule tsena (di thulana, di hulana). Ka hona, n2 / V2 e lekana ka ho toba le ntho e sa fetoheng (bapisa le equation ea van der Waals). Ha boleng ba n bo le boholo2 / V2, ho hohelana ho hoholo pakeng tsa limolek'hule (a).
Ka lehlakoreng le leng, haeba kgatello ya kgase (P) e le nyane, jwale bophahamo ba kgase (V) bo ba boholo. Ha V e hlahella haholo, n e nyane2 / V2. The n e tlase2 / V2, matla a hohelang a pakeng tsa limolek'hule a theoha.
(V – bn) = Phapang pakeng tsa bophahamo ba khase le bophahamo ba kakaretso ba limolek'hule tsa khase. B e sa fetoheng e emela bophahamo ba mole e le 'ngoe ea limolek'hule tsa khase. n = palo ea limolek'hule. Sehlahisoa sa nako pakeng tsa b le n (bn) = bophahamo ba kakaretso ba limolek'hule tsa khase. Haeba khatello ea khase (P) e ba ea bohlokoa haholoanyane, joale bophahamo ba khase (V) boa fokotseha.
Ha V e le nyane, e nyane (V – bn). Sena se bolela hore sebaka se pakeng tsa limolek'hule sea eketseha, 'me, ehlile, ho hohelana pakeng tsa limolek'hule hoa eketseha. Ka lehlakoreng le leng, haeba khatello ea khase e fokotseha, bophahamo ba khase boa eketseha. Ha bophahamo ba khase bo le boholo, boa phahama (V – bn). Ha (V – bn e le kholoanyane), ho hohelana pakeng tsa limolek'hule tsa khase hoa fokola.
Re ka re equation ea boemo ba van der Waals e hlalosa boemo ba 'nete ba khase ka nepo ho feta equation e loketseng ea khase. Ha khatello le bongata ba khase li le kholo ka ho lekaneng, equation ea van der Waals e fana ka liphetho tse nepahetseng haholoanyane. Haeba khatello ea khase e se kholo haholo, joale ( 2 / V 2 ) le (V-bn) li ka hlokomolohuoa, e le hore equation ea boemo ba Van der Waals e fetohe equation e loketseng ea boemo ba khase.
