Umthetho kaBoyle, umthetho kaCharles, umthetho kaGay-Lussac
Umthetho kaBoyle
URobert Boyle (1627-1691) wenza izivivinyo zokuphenya ubudlelwano obulinganiselwe phakathi komfutho wegesi kanye nomthamo. Lokhu kuhlola kwenziwa ngokufaka inani elithile legesi esitsheni esivaliwe. Kuze kube yindlela enhle impela, wathola ukuthi uma izinga lokushisa legesi ligcinwa lingaguquki, khona-ke lapho umfutho wegesi ukhuphuka, umthamo wegesi wehliswa. Ngokufanayo, lapho umfutho wegesi wehla, umthamo wegesi wenyuka. Umfutho wegesi ulingana ngokuphambene nomthamo wegesi. Lobu budlelwano baziwa ngokuthi uMthetho kaBoyle. Ngokwezibalo:
Umthetho kaBoyle ungabhalwa futhi:
I-PV = engaguquki → isibalo 1
P 1 V 1 = P 2 V 2 → isibalo 2
Incazelo yesibalo 1 isezingeni lokushisa elingaguquki (T) uma ingcindezi (P) yegesi ishintsha khona-ke ivolumu (V) yegesi nayo iyashintsha,
ukuze imiphumela yokuphindaphinda phakathi kwengcindezi nomthamo ihlale ingaguquki. Uma ingcindezi yegesi ikhuphuka, umthamo wegesi uyancipha noma okuphambene nalokho uma ingcindezi yegesi iyancipha, umthamo wegesi uyanda, ngakho ukuphindaphinda phakathi kwengcindezi nomthamo kuhlala kungaguquki.
Igrafu echaza ubudlelwano phakathi kwevolumu kanye nengcindezi ibukeka njengesithombeni esingezansi. Ngokusekelwe emiphumeleni yokuhlolwa, uRobert Boyle uthole ukuthi ivolumu yegesi ishintsha ngokungajwayelekile ukuze imigqa egrafuni ibonakale igobile. Ingcindezi eboniswe kugrafu ingcindezi ephelele.
Umthetho kaCharles
Eminyakeni eyikhulu ngemva kokuba uRobert Boyle ethole ubudlelwano phakathi komthamo nokucindezela, usosayensi waseFrance ogama lakhe linguJacques Charles (1746-1823) wahlola ubudlelwano phakathi kokushisa nomthamo wegesi. Ngokusekelwe emiphumeleni yocwaningo, wathola ukuthi lapho umfutho wegesi uhlala ungaguquki, khona-ke lapho izinga lokushisa legesi likhuphuka, umthamo wegesi nawo uyakhuphuka. Ngokuphambene nalokho, lapho izinga lokushisa legesi lehla, umthamo wegesi nawo uyancipha.
Izinguquko kumthamo wegesi ngenxa yezinguquko ekushiseni zenzeka njalo ukuze imigqa ekule grafu ibonakale iqondile. Uma imigqa ekule grafu iboniswa kuze kube yilapho izinga lokushisa liphansi, khona-ke umugqa uzosika i-axis cishe ngo-273 o C.
Ngokusekelwe ezivivinyweni eziningi ezenziwe, kutholakale ukuthi nakuba ubukhulu bokushintsha kwevolumu yegesi ngayinye buyahlukahluka,
uma imigqa eshadini le-VT idonswa ekushiseni okuphansi, umugqa uhlala usika i-axis cishe ku--273 o C. Singasho ukuthi uma igesi ipholisiwe ku--273 o C khona-ke ivolumu yegesi = 0. Uma igesi ipholisiwe futhi kuze kube yilapho izinga lokushisa lingaphansi kuka--273 o C khona-ke ivolumu yegesi izoba negative, into engenakwenzeka.
Ngakho-ke -273 oI-C izinga lokushisa eliphansi kakhulu elingafinyelelwa. Ngoba umugqa uhlangana ne-axis cishe ngo-273 oNgokwesivumelwano, kunqunywa ukuthi izinga lokushisa eliphansi kakhulu elingafinyelelwa lingu-273.15 oC. -273.15 oI-C ibizwa ngokuthi izinga lokushisa eliphelele lika-zero futhi isetshenziswa njengereferensi yesikali esiphelele, eyaziwa nangokuthi isikali sikaKelvin. UKelvin igama likaLord Kelvin (1824-1907), isazi sefiziksi saseBrithani. Kulesi sikali, izinga lokushisa livezwa kuKelvin (K), hhayi kuKelvin (oK) degrees. Ibanga eliphakathi kwamadigri lifana nelesikalini se-centigrade. 0 K = -273.15 oC kanye no-273.15 K = 0 oC.
Izinga lokushisa esikalini seCelsius lingaguqulwa libe isikali seKelvin ngokungeza u-273.15, izinga lokushisa esikalini seKelvin lingaguqulwa libe isikali seCelsius ngokunciphisa u-273.15. Ngokwezibalo:
T (K) = T ( o C) + 273.15
T ( o C) = T (K) – 273.15
T = Izinga lokushisa
K = uKelvin
C = Celsius
Uma izinga lokushisa livezwa esikalini sikaKelvin, ishadi elingenhla lizobukeka njengesithombe esingezansi.
Ngokusekelwe kule grafu, kungaphethwa ngokuthi ngengcindezi engaguquki, ivolumu yegesi ihlala ilingana ngqo nezinga lokushisa eliphelele legesi. Uma izinga lokushisa eliphelele legesi likhuphuka, ivolumu yegesi nayo iyanda, ngokuphambene nalokho, uma izinga lokushisa eliphelele legesi lincipha, ivolumu yegesi nayo incipha. Lobu budlelwano baziwa ngokuthi umthetho kaCharles. Ngokwezibalo:
Ivolumu α Izinga lokushisa → Ingcindezi engaguquki
V α T → P engaguquki
Incazelo yesibalo 1 ingaphansi kwengcindezi engaguquki (P) uma izinga lokushisa eliphelele (T) lishintsha khona-ke ivolumu (V) yegesi nayo iyaphenduka ukuze isilinganiso phakathi kokushisa okuphelele kanye nevolumu sihlale sinjalo. Uma izinga lokushisa eliphelele legesi likhuphuka, ivolumu yegesi nayo iyanda noma okuphambene nalokho uma izinga lokushisa eliphelele legesi lincipha,
ivolumu yegesi nayo iyancipha, ngakho-ke isilinganiso phakathi kwezinga lokushisa nevolumu sihlala singaguquguquki. Izinga lokushisa eliphelele legesi izinga lokushisa legesi, elishiwo esikalini sikaKelvin. Uma izinga lokushisa lisesesikalini sikaCelsius, shintsha kuqala liye esikalini sikaKelvin.
Umthetho kaGay-Lussac
UJoseph Gay-Lussac (1778-1850) wazama futhi wathola ukuthi uma ivolumu yegesi ibekwe njalo, lapho ingcindezi yegesi ikhuphuka, izinga lokushisa eliphelele legesi liyakhuphuka. Ngokufanayo, lapho ingcindezi yegesi yehla, izinga lokushisa eliphelele legesi liyancipha. Kuvolumu eliqhubekayo, ingcindezi yegesi ilingana ngqo nokushisa okuphelele kwegesi. Lobu budlelwano bubizwa ngokuthi uMthetho we-Gay-Lussac. Ngokwezibalo:
Ukucindezela α Izinga Lokushisa → Ivolumu Engaguquki
I-P α T → V ayiguquguquki
Incazelo yesibalo 1 ukuthi ngevolumu engaguquki (V) uma ingcindezi (P) yegesi ishintsha, izinga lokushisa eliphelele (T) legesi nalo liyashintsha ukuze isilinganiso phakathi kwengcindezi kanye nezinga lokushisa eliphelele sihlale njalo. Ngamanye amazwi, uma ingcindezi yegesi ikhuphuka, izinga lokushisa eliphelele legesi nalo liyakhuphuka noma okuphambene nalokho uma ingcindezi yegesi yehla,
izinga lokushisa eliphelele legesi nalo liyancipha, ukuze isilinganiso phakathi kwengcindezi kanye nezinga lokushisa sihlale singaguquguquki.
Izinga lokushisa eliphelele legesi izinga lokushisa legesi, elishiwo esikalini sikaKelvin. Uma izinga lokushisa lisesesikalini sikaCelsius, shintsha kuqala liye esikalini sikaKelvin.
Sicela uqaphele ukuthi umthetho kaBoyle, umthetho kaCharles, kanye nomthetho kaGay-Lussac unikeza imiphumela enembile lapho ingcindezi kanye nobuningi begesi kungabalulekile kakhulu. Ngaphezu kwalokho, le mithetho emithathu isebenza kuphela kugesi okushisa kwayo kungasondelene nendawo yokubila.
Ngokusekelwe kuleli qiniso, kungaphethwa ngokuthi umthetho kaBoyle, umthetho kaCharles, kanye nomthetho kaGay-Lussac awukwazi ukusetshenziswa kuzo zonke izimo zegesi. Ngenxa yokuthi awukwazi ukubhekisela kuzo zonke izimo zegesi zangempela, sidinga umqondo wegesi elifanele. Le gesi elifanele alikho empilweni yansuku zonke. Igesi elifanele liyimodeli elifanele, elifana nomqondo oqinile nowoketshezi ofanele. Ngakho-ke, sicabanga ukuthi imithetho emithathu yegesi engenhla isebenza kuzo zonke izimo zegesi elifanele.
Ekuxazululeni izinkinga zomthetho wegesi, izinga lokushisa kumele lishiwo esikalini sikaKelvin. Uma ingcindezi yegesi isesesimo sokulinganisa ingcindezi, yishintshe kuqala ibe yingcindezi ephelele. Ingcindezi ephelele = ingcindezi yomoya + ingcindezi yokulinganisa
