Su'aalo Tusaale ah iyo Doodo ku saabsan Niyad-jabka Xalka ee Barafka Barafka
Niyad-jabka barta barafowga waa dhacdo muhiim u ah isku-dhafka kiimikada xalka. Waxay saamaysaa habab badan oo bayooloji, kiimiko, iyo warshadeed. Maqaalkani wuxuu ka hadlayaa dhowr tusaale oo ku saabsan niyad-jabka barta barafowga wuxuuna bixinayaa doodo faahfaahsan si loo caddeeyo fikraddan.
Fahmidda Niyad-jabka Barafka
Niyad-jabka barta barafowga waa dhacdada meesha barafka ee dareeraha lagu yareeyo marka lagu daro milanka. Saamayntani waa dhacdo isku-dhafan, taasoo la macno ah in niyad-jabka barta barafowga uu ku xiran yahay tirada walxaha milanka ku jira xalka, oo aan ku xirnayn aqoonsiga milanka.
Isleegga guud ee loo isticmaalo in lagu xisaabiyo niyad-jabka barta barafowga waa:
\[
\Delta T_f = K_f \cdot m
\]
Halkee:
– \(\Delta T_f\) waa niyad-jabka barta barafowga.
– \(K_f\) waa joogto ah oo ah heerka qaboojinta ee dareeraha.
– \(m\) waa molarity-ga xalka (moles of milmay/kg of milmay).
Su'aalo Tusaale ah oo ku saabsan Niyad-jabka Barafka
Su'aal 1aad
Waa la ogyahay:
– Xalka waxaa lagu sameeyaa iyadoo lagu milmo 5 garaam oo NaCl ah (miisaanka molar = 58.5 g/mol) 200 garaam oo biyo ah.
– Joogtada niyad-jabka barta barafowga (K_f) ee biyaha waa 1.86 °C•kg/mol.
Su'aal:
Xisaabi niyad-jabka barta barafowga ee xalkan.
Dood:
1. Xisaabi molarity-ga xalka (m):
Marka hore, waxaan xisaabineynaa tirada burooyinka NaCl:
\[
\text{mol NaCl} = \frac{\text{mass of NaCl (g)}}{\text{miisaanka molar (g/mol)}} = \frac{5 \text{ g}}{58.5 \text{ g/mol}} = 0.0855 \text{ mol}
\]
Kadib, waxaan xisaabineynaa molarity (moles of milde/kg of solvent):
\[
\text{molarity} = \frac{\text{mol NaCl}}{\text{mass of solvent (kg)}} = \frac{0.0855 \text{mol}}{0.2 \text{ kg}} = 0.4275 \text{ m}
\]
2. Xisaabi niyad-jabka barta barafowga (\(\Delta T_f\)):
\[
\Delta T_f = K_f \cdot m = 1.86 \qoraal{ °C•kg/mol} \cdot 0.4275 \qoraal{ m} = 0.79545 \qoraal{ °C}
\]
Markaa, xalkani wuxuu la kulmi doonaa hoos u dhac baraf ah oo ah 0.79545 °C.
Su'aal 2aad
Waa la ogyahay:
– Xalku wuxuu ka kooban yahay 10 garaam oo gulukoos ah (C₆H₁₂O₆, miisaanka molar = 180 g/mol) oo lagu milmay 250 garaam oo biyo ah.
– Joogtada ah ee niyad-jabka dhibicda barafka ee biyaha waa 1.86 °C•kg/mol.
Su'aal:
Waa maxay hoos u dhaca dhibicda barafka ee xalkan gulukooska?
Dood:
1. Xisaabi molarity-ga xalka (m):
Marka hore, waxaan xisaabineynaa tirada burooyinka gulukooska:
\[
\text{mol glucose} = \frac{\text{mass of glucose (g)}}{\text{molar weight (g/mol)}} = \frac{10 \text{ g}}{180 \text{ g/mol}} = 0.0556 \text{ mol}
\]
Kadib, waxaan xisaabineynaa molarity (moles of milde/kg of solvent):
\[
\text{molarity} = \frac{\text{mol glucose}}{\text{mass of solvent (kg)}} = \frac{0.0556 \text{mol}}{0.25 \text{ kg}} = 0.2224 \text{ m}
\]
2. Xisaabi niyad-jabka barta barafowga (\(\Delta T_f\)):
\[
\Delta T_f = K_f \cdot m = 1.86 \qoraal{ °C•kg/mol} \cdot 0.2224 \qoraal{ m} = 0.413664 \qoraal{ °C}
\]
Markaa, xalka gulukoosku wuxuu la kulmi doonaa hoos u dhac ku yimaada barta barafowga oo ah 0.413664 °C.
Su'aal 3aad
Waa la ogyahay:
– Xalka waxaa lagu sameeyaa iyadoo lagu milmo 20 garaam oo urea ah (NH₂CONH₂, miisaanka molar = 60 g/mol) 500 garaam oo biyo ah.
– Joogtada niyad-jabka barta barafowga (K_f) ee biyaha waa 1.86 °C•kg/mol.
Su'aal:
Xisaabi niyad-jabka barta barafowga ee xalkan.
Dood:
1. Xisaabi molarity-ga xalka (m):
Marka hore, waxaan xisaabineynaa tirada burooyinka urea:
\[
\text{mole urea} = \frac{\text{cufnaanta urea (g)}}{\text{molar weight (g/mol)}} = \frac{20 \text{ g}}{60 \text{ g/mol}} = 0.3333 \text{ mol}
\]
Kadib, waxaan xisaabineynaa molarity (moles of milde/kg of solvent):
\[
\text{molarity} = \frac{\text{mol urea}}{\text{mass of solvent (kg)}} = \frac{0.3333 \text{mol}}{0.5 \text{ kg}} = 0.6666 \text{ m}
\]
2. Xisaabi niyad-jabka barta barafowga (\(\Delta T_f\)):
\[
\Delta T_f = K_f \cdot m = 1.86 \qoraal{ °C•kg/mol} \cdot 0.6666 \qoraal{ m} = 1.240476 \qoraal{ °C}
\]
Markaa, xalku wuxuu la kulmi doonaa hoos u dhac baraf ah oo ah 1.240476 °C.
Su'aal 4aad
Waa la ogyahay:
– Xalku wuxuu ka kooban yahay 15 garaam oo asiidh acetic ah (CH₃COOH, miisaanka molar = 60 g/mol) oo lagu milmay 300 garaam oo biyo ah.
– Joogtada niyad-jabka barta barafowga (K_f) ee biyaha waa 1.86 °C•kg/mol.
Su'aal:
Waa maxay hoos u dhaca barafka ee xalkan asiidhka acetic?
Dood:
1. Xisaabi molarity-ga xalka (m):
Marka hore, waxaan xisaabineynaa tirada burooyinka asiidhka acetic:
\[
\text{mol of acetic acid} = \frac{\text{mass of acetic acid (g)}}{\text{molar weight (g/mol)}} = \frac{15 \text{ g}}{60 \text{ g/mol}} = 0.25 \text{ mol}
\]
Kadib, waxaan xisaabineynaa molarity (moles of milde/kg of solvent):
\[
\text{molality} = \frac{\text{mol of acetic acid}}{\text{mass of solvent (kg)}} = \frac{0.25 \text{mol}}{0.3 \text{ kg}} = 0.8333 \text{ m}
\]
2. Xisaabi niyad-jabka barta barafowga (\(\Delta T_f\)):
\[
\Delta T_f = K_f \cdot m = 1.86 \qoraal{ °C•kg/mol} \cdot 0.8333 \qoraal{ m} = 1.55 \qoraal{ °C}
\]
Markaa, xalku wuxuu la kulmi doonaa hoos u dhac baraf ah oo ah 1.55 °C.
Gabagabo
Niyad-jabka bar-barafka waa arrin muhiim ah oo ku saabsan codsiyada sayniska iyo warshadaha kala duwan. Markaan fahamno sida loo xisaabiyo niyad-jabka bar-barafka, waxaan saadaalin karnaa sida xalalka kala duwan ay u saameyn doonaan barta barafowga ee xalka. Maqaalkani wuxuu ka hadlay dhowr dhibaato oo tusaale ah iyo sida loo xisaabiyo niyad-jabka bar-barafka si loo helo xalal, isagoo ku siinaya aasaas adag oo lagu fahmo fikradda niyad-jabka bar-barafka.
