Ngā Tauira Pātai me te Kōrero mō te Whakahekenga o te Ira Hukapapa o ngā Otinga
He āhuatanga nui te whakaheke ira tio i roto i te matū otinga. He pānga ki ngā tukanga koiora, matū, me ngā tukanga ahumahi. E matapakihia ana e tēnei tuhinga ētahi tauira o te whakaheke ira tio, ā, e whakarato ana i ngā kōrero taipitopito hei whakamārama i tēnei ariā.
Te Mārama ki te Pōuritanga o te Ira Huka
Ko te whakahekenga ira tio te āhuatanga e heke ai te ira tio o te whakarewa ina tāpirihia he matūriki ki roto. He āhuatanga whakakotahi tēnei, arā, ko te whakahekenga ira tio e whakawhirinaki ana ki te maha o ngā matūriki matūriki i roto i te otinga, kaua ki te tuakiri o te matūriki.
Ko te whārite whānui e whakamahia ana hei tatau i te whakahekenga o te ira tio ko:
\[
\Delta T_f = K_f \cdot m
\]
Kei hea:
– Ko te whakahekenga o te ira tio ko \(\Delta T_f\).
– Ko te \(K_f\) te pūmau whakaheke ira tio āhua o te whakarewa.
– Ko te \(m\) te molality o te wairewa (ngā mole o te solute/kg o te whakarewa).
Ngā Tauira Pātai mō te Pōuritanga o te Ira Huka
Pātai 1
E mōhiotia ana:
– Ka hangaia he otinga mā te whakarewa i te 5 karamu o te NaCl (taumaha molar = 58.5 karamu/mol) ki roto i te 200 karamu o te wai.
– Ko te pūmau whakaheke ira tio (K_f) o te wai he 1.86 °C•kg/mol.
Pātai:
Tātaihia te hekenga o te ira tio o tēnei otinga.
Kōrero:
1. Tātaihia te mōraiti o te otinga (m):
Tuatahi, ka tatauhia e tātou te maha o ngā mole o NaCl:
\[
\text{mol NaCl} = \frac{\text{papatipu o te NaCl (g)}}{\text{taumaha molar (g/mol)}} = \frac{5 \text{ g}}{58.5 \text{ g/mol}} = 0.0855 \text{ mol}
\]
Kātahi ka tatauhia te molality (ngā mole o te matū wairewa/kg o te matū whakarewa):
\[
\text{molality} = \frac{\text{mol NaCl}}{\text{papatipu o te whakarewa (kg)}} = \frac{0.0855 \text{ mol}}{0.2 \text{ kg}} = 0.4275 \text{ m}
\]
2. Tātaihia te whakahekenga o te ira tio (\(\Delta T_f\)):
\[
\Delta T_f = K_f \cdot m = 1.86 \text{ °C•kg/mol} \cdot 0.4275 \text{ m} = 0.79545 \text{ °C}
\]
Nō reira, ka pāngia tēnei otinga e te hekenga tio o te 0.79545 °C.
Pātai 2
E mōhiotia ana:
– Kei roto i tētahi otinga he 10 karamu o te hukahuka (C₆H₁₂O₆, taumaha molar = 180 karamu/mol) kua rewa i roto i te 250 karamu wai.
– Ko te pūmau whakaheke ira tio mō te wai he 1.86 °C•kg/mol.
Pātai:
He aha te whakahekenga o te ira tio o tēnei otinga huka?
Kōrero:
1. Tātaihia te mōraiti o te otinga (m):
Tuatahi, ka tatauhia e tātou te maha o ngā mole o te hukahuka:
\[
\text{mol hukahuka} = \frac{\text{papatipu o te hukahuka (g)}}{\text{taumaha molar (g/mol)}} = \frac{10 \text{ g}}{180 \text{ g/mol}} = 0.0556 \text{ mol}
\]
Kātahi ka tatauhia te molality (ngā mole o te matū wairewa/kg o te matū whakarewa):
\[
\text{molality} = \frac{\text{mol glucose}}{\text{papatipu o te whakarewa (kg)}} = \frac{0.0556 \text{ mol}}{0.25 \text{ kg}} = 0.2224 \text{ m}
\]
2. Tātaihia te whakahekenga o te ira tio (\(\Delta T_f\)):
\[
\Delta T_f = K_f \cdot m = 1.86 \text{ °C•kg/mol} \cdot 0.2224 \text{ m} = 0.413664 \text{ °C}
\]
Nō reira, ka heke te ira tio o te otinga kurukose ki te 0.413664 °C.
Pātai 3
E mōhiotia ana:
– Ka hangaia he otinga mā te whakarewa i te 20 karamu o te urea (NH₂CONH₂, taumaha molar = 60 karamu/mol) ki roto i te 500 karamu o te wai.
– Ko te pūmau whakaheke ira tio (K_f) o te wai he 1.86 °C•kg/mol.
Pātai:
Tātaihia te hekenga o te ira tio o tēnei otinga.
Kōrero:
1. Tātaihia te mōraiti o te otinga (m):
Tuatahi, ka tatauhia e tātou te maha o ngā mole o te urea:
\[
\text{mole urea} = \frac{\text{papatipu o te urea (g)}}{\text{taumaha molar (g/mol)}} = \frac{20 \text{ g}}{60 \text{ g/mol}} = 0.3333 \text{ mol}
\]
Kātahi ka tatauhia te molality (ngā mole o te matū wairewa/kg o te matū whakarewa):
\[
\text{molality} = \frac{\text{mol urea}}{\text{papatipu o te whakarewa (kg)}} = \frac{0.3333 \text{ mol}}{0.5 \text{ kg}} = 0.6666 \text{ m}
\]
2. Tātaihia te whakahekenga o te ira tio (\(\Delta T_f\)):
\[
\Delta T_f = K_f \cdot m = 1.86 \text{ °C•kg/mol} \cdot 0.6666 \text{ m} = 1.240476 \text{ °C}
\]
Nō reira, ka pāngia te otinga e te hekenga tio o te 1.240476 °C.
Pātai 4
E mōhiotia ana:
– Kei roto i tētahi otinga he 15 karamu o te waikawa acetic (CH₃COOH, taumaha molar = 60 karamu/mol) kua rewa ki te 300 karamu wai.
– Ko te pūmau whakaheke ira tio (K_f) o te wai he 1.86 °C•kg/mol.
Pātai:
He aha te whakahekenga o te ira tio o tēnei otinga waikawa acetic?
Kōrero:
1. Tātaihia te mōraiti o te otinga (m):
Tuatahi, ka tatauhia e mātou te maha o ngā mole o te waikawa acetic:
\[
\text{mol o te waikawa acetic} = \frac{\text{papatipu o te waikawa acetic (g)}}{\text{taumaha molar (g/mol)}} = \frac{15 \text{ g}}{60 \text{ g/mol}} = 0.25 \text{ mol}
\]
Kātahi ka tatauhia te molality (ngā mole o te matū wairewa/kg o te matū whakarewa):
\[
\text{molality} = \frac{\text{mol o te waikawa acetic}}{\text{papatipu o te whakarewa (kg)}} = \frac{0.25 \text{ mol}}{0.3 \text{ kg}} = 0.8333 \text{ m}
\]
2. Tātaihia te whakahekenga o te ira tio (\(\Delta T_f\)):
\[
\Delta T_f = K_f \cdot m = 1.86 \text{ °C•kg/mol} \cdot 0.8333 \text{ m} = 1.55 \text{ °C}
\]
Nō reira, ka pāngia te otinga e te hekenga tio o te 1.55 °C.
Whakamutunga
He āhuatanga nui te whakahekenga ira tio i roto i ngā momo mahi pūtaiao me ngā mahi ahumahi. Mā te mārama ki te tatau i te whakahekenga ira tio, ka taea e tātou te matapae i te pānga o ngā momo matū wairewa ki te whakahekenga ira tio o tētahi otinga. Kua matapakihia e tēnei tuhinga ētahi tauira raruraru me te tatau i te whakahekenga ira tio mō ngā otinga, e whakarato ana i tētahi turanga pakari ki a koe ki te mārama ki te ariā o te whakahekenga ira tio.
