Mibvunzo yeMienzaniso neKukurukurirana kweThermochemical Equations
Thermochemistry ibazi rekemikari rinoongorora shanduko dzesimba dzinoitika panguva yekuchinja kwemakemikari, kunyanya kutamiswa kwekupisa. Thermochemistry inosanganisira pfungwa dzakadai se enthalpy, entropy, uye Gibbs free energy, dzinoshandiswa kufanotaura divi uye kungoerekana kwaita maitiro. Muchinyorwa chino, tichaongorora mimwe mienzaniso yematambudziko uye kukurukura thermochemical equation.
Pfungwa Huru dzeThermochemistry
Usati wapinda mumibvunzo yemuenzaniso nekukurukurirana kwayo, zvakakosha kuziva dzimwe pfungwa dzekutanga dzethermochemistry:
1. Enthalpy (H): Enthalpy imhando yesimba riri muhurongwa hunoyerwa pasi pemamiriro ekumanikidzwa nguva dzose. Kuchinja kwe enthalpy (\( \Delta H \)) kunogona kuratidzwa seizvi:
\[ \Delta H = H_{chigadzirwa} – H_{reactant} \]
2. Maitiro eEndothermic neExothermic:
– Maitiro ekunze (exothermic reactions) maitiro anoburitsa kupisa munzvimbo yakapoteredza (\( \Delta H < 0 \)). - Maitiro ekunze (endothermic reactions) maitiro anotora kupisa kubva munzvimbo yakapoteredza (\( \Delta H > 0 \)).
3. Mutemo waHess: Mutemo waHess unoti shanduko yese ye enthalpy ye chemical reaction yakafanana kunyangwe reaction yacho ikaitika munhanho imwe chete kana nhanho dzakawanda. Inogona kutaurwa seizvi:
\[ \Delta H_{total} = \Delta H_1 + \Delta H_2 + … + \Delta H_n \]
Mibvunzo yemuenzaniso nekukurukurirana
Muenzaniso Mubvunzo 1: Kuverenga Kuchinja kweEnthalpy
Zvichitevera maitiro anotevera:
\[ 2H_2(g) + O_2(g) \museve wekurudyi 2H_2O(l) \]
Kana zvichizivikanwa kuti kuchinja kwe enthalpy pakuumbwa (\( \Delta H_f \)) kwemvura kuri -285.8 kJ/mol. Verenga kuchinja kwe enthalpy yese ye reaction.
Kukurukurirana:
Kuchinja kwe enthalpy kwe reaction (\( \Delta H_{reaction} \)) kunogona kuverengerwa uchishandisa kuchinja kwe enthalpy kwekuumbwa kwezvigadzirwa uye reactants.
Zvinozivikanwa:
– \[ \Delta H_f(H_2O(l)) = -285.8 \text{ kJ/mol} \]
Sezvo mamoles maviri emvura akaumbwa, shanduko yese ye enthalpy yemhinduro ndeiyi:
\[ \Delta H_{reaction} = 2(-285.8 \text{kJ/mol}) \]
\[ \Delta H_{reaction} = -571.6 \text{kJ} \]
Saka, shanduko yese ye enthalpy yeiyi reaction ndeye -571.6 kJ. Iyi reaction i exothermic nekuti \( \Delta H \) haina kunaka.
Muenzaniso Mubvunzo 2: Kushandiswa kweMutemo waHess
Zvichitevera maitiro anotevera:
\[ C(s) + O_2(g) \rightarrow CO_2(g) \hspace{2mm} \text{(1)} \]
\[ C(s) + 1/2 O_2(g) \rightarrow CO(g) \hspace{2mm} \text{(2)} \]
\[ CO(g) + 1/2 O_2(g) \rightarrow CO_2(g) \hspace{2mm} \text{(3)} \]
Zvinozivikanwa:
– \(\Delta H_1 = -393.5 \text{kJ}\)
– \(\Delta H_2 = -110.5 \text{kJ}\)
Verenga shanduko ye enthalpy ye reaction (3).
Kukurukurirana:
Shandisa Mutemo waHess kuti uone shanduko ye enthalpy ye reaction (3). Cherechedza kuti reaction (3) inogona kuumbwa ne reaction (1) na (2):
\[ \text{Reaction } (3): CO(g) + 1/2 O_2(g) \rightarrow CO_2(g) \]
Pindura maitiro (2) kuti ushandise Mutemo waHess:
\[ CO_2(g) \museve wekurudyi C(s) + O_2(g) \hspace{2mm} \text{(inverse 1)}, \Delta H = +393.5 \text{kJ} \]
\[ C(s) + 1/2 O_2(g) \rightarrow CO(g) \hspace{2mm} \text{(2)}, \Delta H = -110.5 \text{kJ} \]
Zvino wedzera mhinduro:
\[ CO_2(g) \museve wekurudyi C(s) + O_2(g) + 1/2 O_2(g) \museve wekurudyi CO(g) + 1/2 O_2(g) \]
\[ CO_2(g) \museve werudyi C(s) + O_2(g) \museve werudyi CO(g) + 1/2 O_2(g) \]
Wedzera shanduko dze enthalpy:
\[ \Delta H_{reaction} = 393.5 – 110.5 \text{kJ}\]
\[ \Delta H_{reaction} = 283.0 \text{kJ}\]
Saka, pakuita \( CO(g) + 1/2 O_2(g) \rightarrow CO_2(g) \), shanduko ye enthalpy ndeye -283.0 kJ.
Muenzaniso Mubvunzo 3: Maitiro eCalorimeter
Kana ukashandisa 100 mL ye1.0 M hydrochloric acid (HCl) uye 100 mL ye1.0 M sodium hydroxide (NaOH). Kana zviviri izvi zvikasanganiswa mu calorimeter, tembiricha inokwira kubva pa25.0 °C kusvika pa31.0 °C. Kana simba rekupisa remvura iri 4.18 J/g°C uye density yemvura iri 1.0 g/mL, verenga shanduko ye enthalpy ye neutralization.
Kukurukurirana:
Kurongeka:
1. Verenga huremu hwemushonga:
\[ \text{Huwandu hwese} = 100 \text{mL} + 100 \text{mL} = 200 \text{mL} \]
\[ \text{Mass} = 200 \text{g} \] (nekuti huwandu hwemushonga i1 g/mL)
2. Verenga shanduko yetembiricha:
\[ \Delta T = 31.0 \chinyorwa{ °C} – 25.0 \chinyorwa{ °C} = 6.0 \chinyorwa{ °C} \]
3. Verenga simba rinotorwa nemushonga:
\[ q = m \cdot c \cdot \Delta T \]
\[ q = 200 \chinyorwa{ g} \nguva 4.18 \chinyorwa{ J/g°C} \nguva 6.0 \chinyorwa{ °C} \]
\[q = 5016 \chinyorwa{J} \]
\[ q = 5.016 \chinyorwa{ kJ} \]
4. Verenga shanduko ye enthalpy:
\[ \Delta H = \frac{q_{\text{solution}}}{\text{mol HCl}} \]
Tichifunga kuti mamoles eHCl neNaOH akafanana:
\[ \text{Moles HCl} = 1.0 \text{M} \times 0.100 \text{L} = 0.100 \text{mol} \]
\[ \Delta H = \frac{5.016 \text{ kJ}}{0.100 \text{ mol}} \]
\[ \Delta H = -50.16 \chinyorwa{ kJ/mol} \]
Saka, shanduko ye enthalpy yekudzikamisa HCl neNaOH i -50.16 kJ/mol, izvo zvinoratidza kuti pane exothermic reaction.
Mhedziso
Thermochemistry ibazi rinokosha rekemesitiri rinotibatsira kunzwisisa kuti simba rinoshandurwa sei uye rinoshandurwa sei mukuita kwemakemikari. Nekunzwisisa pfungwa huru dzakadai se enthalpy nemutemo waHess, uye kukwanisa kudzishandisa kumatambudziko anoshanda, tinogona kufanotaura shanduko dzesimba dzinoitika mukuita kwakasiyana-siyana kwemakemikari. Chinyorwa chino chapa mienzaniso yakati wandei yematambudziko ayo anotarisira kuti achabatsira kusimbisa kunzwisisa kwako kwe thermochemical equations.
