Su'aalo iyo Doodo Tusaale ah oo ku saabsan Isle'egyada Heerkulka
Thermochemistry waa laan ka mid ah kiimikada oo barta isbeddellada tamarta ee dhaca inta lagu jiro falgallada kiimikada, gaar ahaan wareejinta kulaylka. Thermochemistry waxaa ku jira fikradaha sida enthalpy, entropy, iyo tamarta xorta ah ee Gibbs, kuwaas oo loo isticmaalo in lagu saadaaliyo jihada iyo iskeed u falcelinta. Maqaalkan, waxaan ku sahamin doonnaa dhowr dhibaato oo tusaale ah waxaanan ka wada hadli doonnaa isle'egyada thermochemical.
Fikradaha Aasaasiga ah ee Heerkulka Kiimikada
Kahor intaadan gelin su'aalaha tusaalaha ah iyo dooddooda, waa muhiim inaad ogaato qaar ka mid ah fikradaha aasaasiga ah ee thermochemistry:
1. Enthalpy (H): Enthalpy waa nooc ka mid ah tamarta nidaamka lagu cabbiro xaaladaha cadaadiska joogtada ah. Isbeddelka enthalpy (\( \Delta H \)) waxaa lagu tilmaami karaa sidan:
\[ \Delta H = H_{alaabta} – H_{falcelinta} \]
2. Falcelinta Endothermic iyo Exothermic:
– Falgallada kulaylka dibadda waa falgallada kulaylka sii daaya deegaanka (\( \Delta H < 0 \)). - Falgallada kulaylka gudaha waa falgallada nuuga kulaylka deegaanka (\( \Delta H > 0 \)).
3. Sharciga Hess: Sharciga Hess wuxuu sheegayaa in isbeddelka guud ee enthalpy ee falgalka kiimikada uu la mid yahay haddii falgalku ku dhaco hal tallaabo ama dhowr tallaabo. Waxaa lagu tilmaami karaa sidan:
\[ \Delta H_{wadarta} = \Delta H_1 + \Delta H_2 + … + \Delta H_n \]
Su'aalo iyo Doodo Tusaale ah
Su'aal Tusaale ah 1: Xisaabinta Isbeddelka Enthalpy
Marka la eego falcelinta soo socota:
\[ 2H_2(g) + O_2(g) \heerka saxda ah 2H_2O(l) \]
Haddii la og yahay in isbeddelka enthalpy ee samayska (\( \Delta H_f \)) ee biyuhu uu yahay -285.8 kJ/mol. Xisaabi wadarta isbeddelka enthalpy ee falcelinta.
Dood:
Isbeddelka enthalpy ee falgalka (\( \Delta H_{reaction} \)) waxaa lagu xisaabin karaa iyadoo la isticmaalayo isbeddelka enthalpy ee sameynta alaabada iyo falgalayaasha.
Waa la ogyahay:
– \[ \Delta H_f(H_2O(l)) = -285.8 \qoraal{ kJ/mol} \]
Maadaama laba mool oo biyo ah la sameeyay, isbeddelka guud ee enthalpy ee falgalka waa:
\[ \Delta H_{falcelin} = 2(-285.8 \qoraal{ kJ/mol}) \]
\[ \Delta H_{falcelin} = -571.6 \qoraal{ kJ} \]
Markaa, isbeddelka guud ee enthalpy ee falgalkan waa -571.6 kJ. Falgalkani waa mid ka baxsan kulaylka sababtoo ah \( \Delta H \) waa taban.
Su'aal Tusaale 2: Isticmaalka Sharciga Hess
Marka la eego falcelinta soo socota:
\[ C(s) + O_2(g) \rightarrow CO_2(g) \hspace{2mm} \text{(1)} \]
\[ C(s) + 1/2 O_2(g) \rightarrow CO(g) \hspace{2mm} \text{(2)} \]
\[ CO(g) + 1/2 O_2(g) \rightarrow CO_2(g) \hspace{2mm} \text{(3)} \]
Waa la ogyahay:
– \(\Delta H_1 = -393.5 \qoraal{ kJ}\)
– \(\Delta H_2 = -110.5 \qoraal{ kJ}\)
Xisaabi isbeddelka enthalpy si aad u hesho falcelin (3).
Dood:
Adeegso Sharciga Hess si aad u go'aamiso isbeddelka enthalpy ee falcelinta (3). Ogsoonow in falcelinta (3) ay ka koobnaan karto falcelin (1) iyo (2):
\[ \text{Falcelin } (3): CO(g) + 1/2 O_2(g) \rightarrow CO_2(g) \]
Falcelinta rogidda (2) si loo isticmaalo Sharciga Hess:
\[ CO_2(g) \rightarrow C(s) + O_2(g) \hspace{2mm} \text{(rogaal celi 1)}, \Delta H = +393.5 \text{ kJ} \]
\[ C(s) + 1/2 O_2(g) \rightarrow CO(g) \hspace{2mm} \text{(2)}, \Delta H = -110.5 \text{ kJ} \]
Hadda isku dar falcelinta:
\[ CO_2(g) \rightarrow C(s) + O_2(g) + 1/2 O_2(g) \rightarrow CO(g) + 1/2 O_2(g) \]
\[ CO_2(g) \rightarrow C(s) + O_2(g) \rightarrow CO(g) + 1/2 O_2(g) \]
Isku dar isbeddellada enthalpy:
\[ \Delta H_{falcelin} = 393.5 – 110.5 \qoraal{ kJ}\]
\[ \Delta H_{falcelin} = 283.0 \qoraal{ kJ}\]
Markaa, falcelinta \( CO(g) + 1/2 O_2(g) \rightarrow CO_2(g) \), isbeddelka enthalpy waa -283.0 kJ.
Su'aal Tusaale ah 3: Falcelinta Kalorimeter-ka
Marka la siiyo 100 mL oo ah 1.0 M hydrochloric acid (HCl) iyo 100 mL oo ah 1.0 M sodium hydroxide (NaOH). Marka labada lagu qaso kaloorimeter, heerkulku wuxuu ka kordhaa 25.0 °C ilaa 31.0 °C. Haddii awoodda kulaylka ee xalka biyaha ku jira ay tahay 4.18 J/g°C iyo cufnaanta xalka ay tahay 1.0 g/mL, xisaabi isbeddelka enthalpy ee dhexdhexaadnimada.
Dood:
Talaabooyinka:
1. Xisaabi cufka xalka:
\[ \text{Wadarta mugga} = 100 \text{ mL} + 100 \text{ mL} = 200 \text{ mL} \]
\[ \text{Mass} = 200 \text{ g} \] (sababtoo ah cufnaanta xalka waa 1 g/mL)
2. Xisaabi isbeddelka heerkulka:
\[ \Delta T = 31.0 \qoraal{ °C} – 25.0 \qoraal{ °C} = 6.0 \qoraal{ °C} \]
3. Xisaabi tamarta uu nuugay xalka:
\[ q = m \cdot c \cdot \Delta T \]
\[ q = 200 \qoraal{ g} \jeer 4.18 \qoraal{ J/g°C} \jeer 6.0 \qoraal{ °C} \]
\[ q = 5016 \qoraal{ J} \]
\[ q = 5.016 \qoraal{ kJ} \]
4. Xisaabi isbeddelka enthalpy:
\[ \Delta H = \frac{q_{\text{solution}}}{\text{mol HCl}} \]
Marka la eego in burooyinka HCl iyo NaOH ay isku mid yihiin:
\[ \text{Moles HCl} = 1.0 \text{ M} \times 0.100 \text{ L} = 0.100 \text{ mol} \]
\[ \Delta H = \frac{5.016 \text{ kJ}}{0.100 \text{ mol}} \]
\[ \Delta H = -50.16 \qoraal{ kJ/mol} \]
Sidaa darteed, isbeddelka enthalpy ee dhexdhexaadinta HCl iyo NaOH waa -50.16 kJ/mol, taasoo muujinaysa falcelinta kuleylka dibadda.
Gabagabo
Heerkulku waa laan muhiim ah oo kiimiko ah oo naga caawisa inaan fahanno sida tamarta loo beddelo loona beddelo falgallada kiimikada. Annagoo fahannayna fikradaha aasaasiga ah sida enthalpy iyo sharciga Hess, iyo awood u yeelashada inaan ku dabaqno dhibaatooyinka wax ku oolka ah, waxaan saadaalin karnaa isbeddellada tamarta ee ka dhaca falgallada kiimikada ee kala duwan. Maqaalkani wuxuu soo bandhigay dhowr dhibaato oo tusaale ah oo rajeynaya inay kaa caawin doonaan xoojinta fahamkaaga isle'egyada thermochemical.
