Li-Thermochemical Equation: Ho Utloisisa Melao-motheo ea Motheo ea Matla Likarabelong tsa Lik'hemik'hale
Pendahuluan
Thermochemistry ke lekala la k'hemistri le amehang ka liphetoho tsa matla, haholo-holo mocheso, liketsong tsa lik'hemik'hale. Kutloisiso ea thermochemistry e bohlokoa bakeng sa lits'ebetso tse ngata tsa saense le tsa indasteri, ho kenyeletsoa nts'etsopele ea mafura, tlhahiso ea lik'hemik'hale le lithuto tsa phetoho ea maemo a leholimo. Sengoloa sena se tla tšohla melao-motheo ea motheo ea thermochemistry, ka ho tsepamisa maikutlo haholo ho li-equation tsa thermochemical, e leng mohopolo oa mantlha thutong ea liphetoho tsa matla liketsong tsa lik'hemik'hale.
Tlhaloso ea Thermochemistry
Thermochemistry e bolela thuto ea liphetoho tsa matla tse tsamaeang le lik'hemik'hale le liphetoho tsa boemo. Karolo e 'ngoe ea motheo ea thermochemistry ke kamoo matla ka mokhoa oa mocheso a fapanyetsanoang kateng pakeng tsa sistimi (li-reactant le lihlahisoa) le tikoloho ea eona nakong ea karabelo ea lik'hemik'hale. Sena hangata se hloka kutloisiso ea molao oa pele oa thermodynamics, o bolelang hore matla a ke ke a bōptjoa kapa a timetsoa, empa a ka fetola sebopeho feela.
Molao oa Pele oa Thermodynamics
Molao oa pele oa thermodynamics, o tsejoang hape e le molao oa paballo ea matla, o re:
\[ \Delta U = q + W \]
Moo \( \Delta U \) e leng phetoho matleng a ka hare a sistimi, \( q \) ke mocheso o eketsoang tsamaisong, mme \( W \) ke mosebetsi o etswang ke sistimi. Bakeng sa karabelo ya dikhemikhale e hlahang kgatellong e sa kgaotseng, mocheso o eketswang kapa o lokollwang (\( q_p \)) o lekana le phetoho ya enthalpy (\( \Delta H \)).
Likarabelo tsa Enthalpy le Lik'hemik'hale
Enthalpy (H) ke lentsoe le sebelisetsoang ho hlalosa matla ohle tsamaisong, ho kenyeletsoa matla a ka hare le matla a hlokahalang ho lula sebakeng tikolohong e fanoeng ka khatello e sa khaotseng. Phetoho ea enthalpy (\( \Delta H \)) nakong ea karabelo ea lik'hemik'hale e fana ka pontšo ea hore na karabelo ke exothermic (e lokollang mocheso) kapa endothermic (mocheso o monyang).
– Karabelo ea Exothermic: \( \Delta H \) ha e negative, ho bolelang hore sistimi e ntsha mocheso tikolohong.
– Karabelo ea Endothermic: \( \Delta H \) e ntle, ho bolelang hore sistimi e monya mocheso tikolohong.
Litekanyo tsa Thermochemical
Tekanyo ea thermochemical ke setšoantšo sa stoichiometric sa karabelo ea lik'hemik'hale e kenyeletsang liphetoho tsa matla ka mokhoa oa enthalpy. Tekanyo ena e ngotsoe ka tsela e latelang:
\[ \text{Reactants} \rightarrow \text{Products} \quad \Delta H = \text{value} \]
Mohlala, karabelo ea ho tuka ha methane e ka ngoloa tjena:
\[ \text{CH}_4(g) + 2 \text{O}_2(g) \rightarrow \text{CO}_2(g) + 2 \text{H}_2\text{O(l)} \quad \Delta H = -890 \text{kJ} \]
Palo \(-890 \text{kJ}\) e bontša hore 890 kJ ea matla e lokolloa tikolohong bakeng sa mole e 'ngoe le e 'ngoe ea methane e chesitsoeng. Ena ke mohlala oa karabelo ea exothermic.
Enthalpy e Tloaelehileng ea Sebopeho
Enthalpy e tloaelehileng ea ho thehoa (\( \Delta H_f^\circ \)) ke phetoho ea enthalpy e hlahang ha mole e le 'ngoe ea motsoako e thehoa ho tsoa ho likarolo tse maemong a tsona a tloaelehileng ka khatello ea 1 atm le mocheso o itseng, hangata 25°C. Boleng ba \(\Delta H_f^\circ \) bo bohlokoa haholo bakeng sa ho fumana phetoho ea enthalpy ea lik'hemik'hale tse rarahaneng ho sebelisoa molao oa Hess.
Molao oa Hess
Molao oa Hess o bolela hore phetoho e felletseng ea enthalpy ea karabelo ea lik'hemik'hale e tšoana ho sa tsotelehe tsela e nkiloeng ke karabelo. Sena se bolela hore haeba karabelo e ka aroloa ka mehato e 'maloa, joale kakaretso ea \(\Delta H \) ke kakaretso ea \(\Delta H \) ea mohato ka mong. Molao oa Hess o ka ngoloa tjena:
\[ \Delta H_{\text{total reaction}} = \sum \Delta H_{\text{steps}} \]
Mohlala o bonolo oa molao oa Hess ke ho fumana \(\Delta H \) bakeng sa karabelo:
\[ \text{C(graphite)} + \frac{1}{2} \text{O}_2(g) \rightarrow \text{CO(g)} \]
ho sebelisa lintlha tse latelang:
1. \(\text{C(graphite)} + \text{O}_2(g) \rightarrow \text{CO}_2(g) \quad \Delta H = -393.5 \text{kJ}\)
2. \(\text{CO(g)} + \frac{1}{2} \text{O}_2(g) \rightarrow \text{CO}_2(g) \quad \Delta H = -283 \text{kJ}\)
Ka ho hlophisoa ha equation ena, phetoho ea enthalpy ke:
\[ \Delta H = (-393.5 \mongolo{kJ}) – (-283 \mongolo{kJ}) = -110.5 \mongolo{kJ} \]
Kahoo, \(\Delta H \) bakeng sa ho thehoa ha CO(g) ho tsoa ho graphite le oksijene ke \(-110.5 \text{kJ}\).
Matla a Tlamo
Matla a bond ke matla a hlokahalang ho roba mole e le 'ngoe ea litlamo ka har'a molek'hule ea khase. Tsebo ea matla a bond e re lumella ho bala phetoho ea enthalpy ea karabelo ea lik'hemik'hale ho latela palo le mefuta ea litlamo tse robehileng le ho thehoa. Mohlala, karabelong ea karohano ea molek'hule ea haedrojene (\(\text{H}_2 \rightarrow 2\text{H}\)), haeba matla a bond a H-H e le 436 kJ/mol, joale 436 kJ ea hlokahala ho roba mole e le 'ngoe ea \(\text{H}_2\).
Litšebeliso tsa Thermochemical Equations
Li-equation tsa thermochemical ha li bohlokoa feela lilaboratoring tsa k'hemistri, empa hape le lits'ebetsong tse fapaneng tse sebetsang.
1. Indasteri ea Matla: Ho utloisisa matla a ho chesa mafura a khale le biomass.
2. Boenjiniere ba Lik'hemik'hale: Ho rala li-reactor tsa lik'hemik'hale, ho ntlafatsa maemo a ts'ebetso bakeng sa ts'ebeliso e ntle ea matla.
3. Bophelo bo Botle le Bongaka: Ho rala meriana ho latela liphetoho tsa matla sebopehong le ho senyeha ha metsoako ea lik'hemik'hale.
4. Tikoloho: Ho utloisisa le ho fokotsa litlamorao tsa matla tsa lits'ebetso tsa indasteri phetohong ea tlelaemete.
Qetello
Thermochemistry e fana ka moralo o matla oa ho utloisisa le ho bolela esale pele liphetoho tsa matla liketsong tsa lik'hemik'hale. Re sebelisa li-equation tsa thermochemical, re ka bala liphetoho tsa enthalpy 'me ra bolela esale pele hore na karabelo e tla ba ea endothermic kapa ea exothermic. Tšebeliso ea thermochemistry masimong a fapaneng e bontša bohlokoa ba ho utloisisa liphetoho tsena tsa matla bophelong ba letsatsi le letsatsi le indastering ea sejoale-joale. Ha re tsoela pele, nts'etsopele ea mahlale a tsitsitseng e tla itšetleha haholo ka melao-motheo ea motheo e rutoang ke thermochemistry.
