Lipotso tsa Mehlala le Puisano ea Phahamiso ea Litharollo tsa Ntlha e Belang
Pendahuluan
Ho phahama ha ntlha e belang ke ketsahalo e etsahalang ha solute e eketsoa ho solvent. Ketsahalo ena e bua ka keketseho ea ntlha e belang ea tharollo ha e bapisoa le ntlha e belang ea solvent e hloekileng. K'hemistri, ho utloisisa bophahamo ba ntlha e belang ho bohlokoa, haholo-holo moelelong oa liketso tsa lik'hemik'hale, mekhoa ea karohano le tlhahlobo ea meriana. Sehlooho sena se ikemiselitse ho hlahisa mehlala e fapaneng ea mathata le lipuisano tse amanang le mohopolo oa ho phahama ha ntlha e belang.
Khopolo-taba ea Motheo
Ho phahama ha ntlha e belang ke ketsahalo eo ho yona ntlha e belang ya tharollo e leng hodimo ho feta ntlha e belang ya tharollo e hlwekileng. Ha ho eketswa solute (e sa fetoheng) ho solvent, kgatello ya mouoane ya tharollo e a fokotseha. Ka lebaka leo, ho hlokahala mocheso o phahameng ho fihlella kgatello e tshwanang ya mouoane le kgatello ya kantle. Ka hona, ntlha e belang ya tharollo e hodimo.
Tekanyo e sebelisetsoang ho bala bophahamo ba ntlha e belang ke:
\[ \Delta T_b = K_b \cdot m \]
Di mana:
– \(\Delta T_b\) = bophahamo ba ntlha e belang,
– \(K_b\) = e sa fetoheng ya ebulioscopic (e fapana bakeng sa solvent ka nngwe),
– \(m\) = molality ea tharollo (li-moles tsa solute ka kilogram ea solvent).
Lipotso tsa Mehlala le Puisano
A re buisaneng ka mehlala e meng ea mathata ho utloisisa khopolo ena hamolemo.
Mohlala oa Potso ea 1
Potso: Phahamo ea ntlha ea ho belisa ea tharollo e nang le li-mole tse 2 tsa glucose (\(C_6H_{12}O_6\)) e qhibilihisitsoeng ka har'a 1 kg ea metsi ke efe? Hoa tsebahala hore botsitso ba ebulioscopic ba metsi (\(K_b\)) ke 0,512 °C·kg/mol.
Puisano:
1. Fumana hore na tharollo e na le molality hakae:
\[ m = \frac{\text{moles of solute}}{\text{kg solvent}} = \frac{2 \; \text{mol}}{1 \; \text{kg}} = 2 \; \text{m} \]
2. Bala bophahamo ba ntlha e belang o sebedisa equation:
\[ \Delta T_b = K_b \cdot m \]
\[ \Delta T_b = 0.512 \; °C·kg/mol \makgetlo a 2 \; m\]
\[ \Delta T_b = 1.024 °C \]
Kahoo, keketseho ea ntlha ea ho belisa ea tharollo ke 1.024 °C.
Mohlala oa Potso ea 2
Potso: Bala bophahamo ba ntlha e belang bakeng sa tharollo e nang le 0,3 mol ea NaCl ka ligrama tse 500 tsa metsi (\(K_b\) metsi = 0.512 °C·kg/mol). Nka hore NaCl e arohana ka botlalo ka metsing.
Puisano:
1. Fumana hore na tharollo e na le molality hakae:
\[ \text{Boima ba solvent ka kg} = 500 \; \text{g} = 0.5 \; \text{kg} \]
\[ m = \frac{\text{moles of solute}}{\text{kg solvent}} = \frac{0.3 \; \text{mol}}{0.5 \; \text{kg}} = 0.6 \; \text{m} \]
2. Kaha NaCl e arohana ho ba li-ion tsa \(Na^+\) le \(Cl^-\) , palo yohle ya dikarolwana e feta habeli palo ya dimolek'hule tsa NaCl tse teng.
\[ i = 2 \; (\text{van 't Hoff factor bakeng sa NaCl}) \]
3. Bala bophahamo ba ntlha e belang o sebedisa equation:
\[ \Delta T_b = K_b \cdot m \cdot i \]
\[ \Delta T_b = 0.512 \; °C·kg/mol \ka makhetlo a 0.6 \; m \ka makhetlo a 2 \]
\[ \Delta T_b = 0.6144 °C \]
Kahoo, keketseho ea ntlha ea ho belisa ea tharollo ke 0.6144 °C.
Mohlala oa Potso ea 3
Potso: Keketseho ea ntlha ea ho belisa ke efe haeba 0.5 mol ea sucrose (\(C_{12}H_{22}O_{11}\)) e qhibiliha ka har'a 1.5 kg ea metsi? \(K_b\) ea metsi = 0.512 °C·kg/mol.
Puisano:
1. Fumana hore na tharollo e na le molality hakae:
\[ m = \frac{\text{moles of solute}}{\text{kg solvent}} = \frac{0.5 \; \text{mole}}{1.5 \; \text{kg}} = \frac{0.5}{1.5} \; \text{m} = 0.333 \; \text{m} \]
2. Kaha sucrose ha e arohane, ntlha ea van 't Hoff (\(i\)) ke 1.
3. Bala bophahamo ba ntlha e belang o sebedisa equation:
\[ \Delta T_b = K_b \cdot m \]
\[ \Delta T_b = 0.512 \; °C·kg/mol \makgetlo a 0.333 \; m\]
\[ \Delta T_b = 0.1705 °C \]
Kahoo, keketseho ea ntlha ea ho belisa ea tharollo ke 0.1705 °C.
Mohlala oa Potso ea 4
Potso: Tharollo e entsoeng ka 0.25 mol ea urea (\(NH_2CONH_2\)) ka ligrama tse 2000 tsa metsi e na le bophahamo boemong ba ho belisa. Bala bophahamo boemong ba ho belisa. \(K_b\) bakeng sa metsi ke 0.512 °C·kg/mol.
Puisano:
1. Fumana hore na tharollo e na le molality hakae:
\[ \text{Boima ba solvent ka kg} = 2000 \; \text{g} = 2 \; \text{kg} \]
\[ m = \frac{\text{moles of solute}}{\text{kg solvent}} = \frac{0.25 \; \text{mol}}{2 \; \text{kg}} = 0.125 \; \text{m} \]
2. Kaha urea ha e arohane ka metsing, van 't Hoff factor (\(i\)) ke 1.
3. Bala bophahamo ba ntlha e belang o sebedisa equation:
\[ \Delta T_b = K_b \cdot m \]
\[ \Delta T_b = 0.512 \; °C·kg/mol \makgetlo a 0.125 \; m\]
\[ \Delta T_b = 0.064 \; °C\]
Kahoo, keketseho ea ntlha ea ho belisa ea tharollo ke 0.064 °C.
Qetello
Ho phahama ha ntlha e belang ke mohopolo oa bohlokoa k'hemistring o hlalosang kamoo solute e amang ntlha e belang ea tharollo kateng. Mohlala oa bothata bo kaholimo o bontša mokhoa oa ho bala bophahamo ba ntlha e belang u sebelisa likhopolo tsa molality le van 't Hoff factor. Tsebo ena e na le thuso lits'ebetsong tse fapaneng tsa k'hemistri, ho kenyeletsoa tlhahlobo ea laboratori le nts'etsopele ea lithethefatsi. Ho utloisisa ketsahalo ena ho fana ka temohisiso e tebileng mabapi le litšobotsi tsa lintho tse ka har'a tharollo.
