Tauira Pātai me te Kōrero mō te Whakatipuranga o te Pūwāhi Kohua o ngā Otinga
Pendahuluan
Ko te whakanui i te pūwāhi kohua he āhuatanga whakakotahi e puta ana ina tāpirihia he matū whakarewa ki te whakarewa. E pā ana tēnei āhuatanga ki te pikinga o te pūwāhi kohua o te otinga ki te whakataurite ki te pūwāhi kohua o te whakarewa parakore. I roto i te matū, he mea nui te mārama ki te whakanui i te pūwāhi kohua, inā koa i roto i te horopaki o ngā tauhohenga matū, ngā tukanga wehenga, me te tātari rongoā. Ko te whāinga o tēnei tuhinga he whakaatu i ngā tauira raruraru me ngā kōrero e pā ana ki te ariā o te whakanui i te pūwāhi kohua.
Ariā Taketake
Ko te pikinga o te ira koropupū he āhuatanga e teitei ake ai te ira koropupū o te wairewa i te ira koropupū o te whakarewa parakore. Ina tāpirihia he matū kore-pūngoi ki te whakarewa, ka heke te pēhanga kohu o te whakarewa. Nō reira, me teitei ake te pāmahana kia rite ai te pēhanga kohu ki te pēhanga o waho. Nō reira, ka teitei ake te ira koropupū o te wairewa.
Ko te whārite i whakamahia hei tatau i te pikinga o te ira koropupū ko:
\[ \Delta T_b = K_b \cdot m \]
Kei hea:
– \(\Delta T_b\) = te pikinga o te pūwāhi koropupū,
– \(K_b\) = pūmau ebulioscopic (he rerekē mō ia whakarewa),
– \(m\) = te mōrahi o te wairewa (ngā mōrahi o te matū wairewa mō ia kirokaramu o te wairewa).
Ngā Pātai Tauira me te Kōrero
Me matapakihia ētahi tauira raruraru kia pai ake ai te mārama ki tēnei ariā.
Tauira Pātai 1
Pātai: He aha te teitei o te pāmahana koropupū o tētahi otinga kei roto e 2 ngā mole o te hukahuka (\(C_6H_{12}O_6\)) kua rewa i roto i te 1 kg o te wai? E mōhiotia ana ko te pūmau ebulioscopic o te wai (\(K_b\)) he 0,512 °C·kg/mol.
Kōrero:
1. Whakatauhia te mōraiti o te otinga:
\[ m = \frac{\text{ngā ira o te matū whakarewa}}{\text{kg matū whakarewa}} = \frac{2 \; \text{mol}}{1 \; \text{kg}} = 2 \; \text{m} \]
2. Tātaihia te pikinga o te pūwāhi koropupū mā te whakamahi i te whārite:
\[ \Delta T_b = K_b \cdot m \]
\[ \Delta T_b = 0.512 \; °C·kg/mol \times 2 \; m\]
\[ \Delta T_b = 1.024 °C \]
Nō reira, ko te pikinga o te pāmahana koropupū o te wairewa he 1.024 °C.
Tauira Pātai 2
Pātai: Tātaihia te pikinga o te pūmahana koropupū mō tētahi wairewa kei roto ko te 0,3 mol o te NaCl i roto i te 500 karamu wai (\(K_b\) wai = 0.512 °C·kg/mol). Me kī ka memeha katoa te NaCl i roto i te wai.
Kōrero:
1. Whakatauhia te mōraiti o te otinga:
\[ \text{Taumaha o te whakarewa i roto i te kg} = 500 \; \text{g} = 0.5 \; \text{kg} \]
\[ m = \frac{\text{ngā ira o te matū whakarewa}}{\text{kg matū whakarewa}} = \frac{0.3 \; \text{mol}}{0.5 \; \text{kg}} = 0.6 \; \text{m} \]
2. Nā te mea ka wehea te NaCl hei iona \(Na^+\) me \(Cl^-\), ko te tapeke o ngā matūriki he rua te maha o ngā ngota NaCl e kitea ana.
\[ i = 2 \; (\text{tauwehenga van 't Hoff mō te NaCl}) \]
3. Tātaihia te pikinga o te pūwāhi koropupū mā te whakamahi i te whārite:
\[ \Delta T_b = K_b \cdot m \cdot i \]
\[ \Delta T_b = 0.512 \; °C·kg/mol \times 0.6 \; m \times 2 \]
\[ \Delta T_b = 0.6144 °C \]
Nō reira, ko te pikinga o te pāmahana koropupū o te wairewa he 0.6144 °C.
Tauira Pātai 3
Pātai: He aha te pikinga o te pāmahana koropupū mēnā ka rewa te 0.5 mol o te sucrose (\(C_{12}H_{22}O_{11}\)) ki roto i te 1.5 kg o te wai? \(K_b\) o te wai = 0.512 °C·kg/mol.
Kōrero:
1. Whakatauhia te mōraiti o te otinga:
\[ m = \frac{\text{ngā ira o te matū wairewa}}{\text{kg te matū wairewa}} = \frac{0.5 \; \text{mole}}{1.5 \; \text{kg}} = \frac{0.5}{1.5} \; \text{m} = 0.333 \; \text{m} \]
2. Nā te mea kāore te sucrose e wehea, ko te tauwehe van 't Hoff (\(i\)) he 1.
3. Tātaihia te pikinga o te pūwāhi koropupū mā te whakamahi i te whārite:
\[ \Delta T_b = K_b \cdot m \]
\[ \Delta T_b = 0.512 \; °C·kg/mol \times 0.333 \; m\]
\[ \Delta T_b = 0.1705 °C \]
Nō reira, ko te pikinga o te pāmahana koropupū o te wairewa he 0.1705 °C.
Tauira Pātai 4
Pātai: Ka piki ake te pāmahana koropupū o tētahi otinga i hangaia mai i te 0.25 mol o te urea (\(NH_2CONH_2\)) i roto i te 2000 karamu o te wai. Tātaihia te pāmahana koropupū. Ko te \(K_b\) mō te wai he 0.512 °C·kg/mol.
Kōrero:
1. Whakatauhia te mōraiti o te otinga:
\[ \text{Taumaha o te whakarewa i roto i te kg} = 2000 \; \text{g} = 2 \; \text{kg} \]
\[ m = \frac{\text{ngā ira o te matū whakarewa}}{\text{kg matū whakarewa}} = \frac{0.25 \; \text{mol}}{2 \; \text{kg}} = 0.125 \; \text{m} \]
2. Nā te mea kāore te urea e memeha i roto i te wai, ko te tauwehe van 't Hoff (\(i\)) he 1.
3. Tātaihia te pikinga o te pūwāhi koropupū mā te whakamahi i te whārite:
\[ \Delta T_b = K_b \cdot m \]
\[ \Delta T_b = 0.512 \; °C·kg/mol \times 0.125 \; m\]
\[ \Delta T_b = 0.064 \; °C\]
Nō reira, ko te pikinga o te pāmahana koropupū o te wairewa he 0.064 °C.
Whakamutunga
He ariā nui te whakanui i te pūwāhi koropupū i roto i te matū e whakamārama ana i te pānga o te matū wairewa ki te pūwāhi koropupū o te otinga. E whakaatu ana te tauira raruraru i runga ake nei me pēhea te tatau i te whakanui i te pūwāhi koropupū mā te whakamahi i ngā ariā o te molality me te tauwehe van 't Hoff. He whai hua tēnei mātauranga i roto i ngā momo tono matū, tae atu ki te tātari taiwhanga me te whakawhanaketanga rongoā. Mā te mārama ki tēnei āhuatanga ka hohonu ake te māramatanga ki ngā āhuatanga o ngā matū i roto i te otinga.
