Molal ịta. Gịnị ka ọ pụtara ezengwenri na molal ịta?

Ezengwenri na molal ịta, n'agbanyeghị yiri aha, ụkpụrụ dị iche iche. Isi ihe dị iche bụ na ha na-ekpebi ndị molal ịta ngụkọta oge na-mere bụghị na olu nke ihe ngwọta dị ka nchọpụta molarity, mgbe arọ nke mgbaze.

General ọmụma banyere ihe ngwọta na solubility

Ezi ngwọta na-akpọ homogeneous usoro, nke na-agụnye ya mejupụtara a ọnụ ọgụgụ nke mmiri, nọọrọ onwe ha onye ọ bụla ọzọ. Otu n'ime ha bụ ihe mgbaze, na ndi fọduru ndị bekee etisasịwo na ya. The mgbaze-atụle ga-àkù na ihe ngwọta nke kasị.

Solubility - a umi na ndị ọzọ bekee na-etolite a homogeneous usoro - ngwọta nke ọ bụ na ụdị onye atọm, ion, ụmụ irighiri ma ọ bụ ahụ. A ịta - a ọtụtụ nke solubility.

N'ihi ya, solubility nke bekee bụ ike na-ekesa uniformly n'ụdị elementrị ahụ ofụri olu nke mgbaze.

Ezi ngwọta na-nkewa dị ka ndị a:

• site ụdị mgbaze - na-abụghị okenye na mmiri;
• site ụdị solute - aputa ngwọta, asịd, alkalis, salts, etc.;
• maka mmekọrịta ihe eletrik - electrolytes (bekee nwere eletriki conductivity) na na-abụghị electrolytes (bekee bụghị ike nke na eletriki conductivity);
• nke ịta - diluted na lekwasị.

The ịta na n'aka ya okwu

Ịta oku ọdịnaya (arọ) nke a umi etisasịwo a ụfọdụ ego (arọ ma ọ bụ olu) nke mgbaze, ma ọ bụ na a kọwaa olu nke ngụkọta ngwọta. Ọ na-eme ndị na-esonụ ụdị:

1. The ịta nke mmasị (kwupụtara na%) - ọ na-agwa otú ọtụtụ grams nke solute dị na 100 grams nke ngwọta.

2. ezengwenri ịta - bụ nọmba nke gram ntụpọ ojii n'ahụ kwa 1 liter nke ihe ngwọta. Ọ na-egosi otú ọtụtụ gram-irighiri dị na 1 liter nke ihe ngwọta nke umi.

3. The nkịtị ịta - bụ nọmba nke gram-kachasị yitebe kwa 1 liter nke ihe ngwọta. Ọ na-egosi otú nwere gram kachasị yitebe nke a solute na 1 liter nke ihe ngwọta.

4. molal ịta-egosi otú ọtụtụ ntụpọ ojii n'ahụ nke solute na ego kwa 1 kilogram nke mgbaze.

5. Titer ekpebi ọdịnaya (na grams) nke solute etisasịwo ke 1 milliliter nke ngwọta.

Ezengwenri na molal kasịnụ dị iche iche onye ọ bụla ọzọ. Tụlee ha n'otu n'otu e ji mara.

The ezengwenri ịta

The usoro maka ịchọpụta ya:

CV = (v / V), nke

v - nọmba nke bekee etisasịwo mol;

V - mkpokọta olu nke ngwọta liter ma ọ bụ ^m3.

Ka ihe atụ, "0,1 M ngwọta nke H ₂ NKE _4" na-egosi na na 1 liter nke dị otú ahụ ngwọta bụ ugbu 0,1 mol (9.8 g) nke na igirigi ibu sulphuric acid .

molal ịta

Ị mgbe niile kwesịrị gaa na akaụntụ eziokwu ahụ bụ na molal na ezengwenri kasịnụ nwere kpamkpam dị iche iche pụtara.

Gịnị bụ molal ịta nke ihe ngwọta? The usoro maka ịchọpụta na ọ bụ:

Cm = (v / m), ebe

v - nọmba nke bekee etisasịwo mol;

m - uka nke mgbaze, n'arọ.

Ka ihe atụ, Ndekọ 0,2 M NaOH ngwọta pụtara na 1 kilogram nke mmiri (na nke a, ya bụ mgbaze) dissolving 0,2 mol NaOH.

Ọzọ formulas mkpa maka mgbawa

Ọtụtụ inyeaka ọmụma nwere ike a chọrọ iji na-molal ịta a gbakọtara. Usoro, nke nwere ike ịbụ bara uru n'ihi na idozi isi nsogbu ndị dị ka ndị.

Eji ego nke umi ν aghọta a ụfọdụ ọnụ ọgụgụ nke atọm, electrons, irighiri, ion ma ọ bụ ndị ọzọ ahụ ya.

v = m / M = N / N A = V / V m, ebe:

• m - uka nke compound, g ma ọ bụ n'arọ;
• M - ezengwenri uka, g (ma ọ bụ kg) / mol;
• N - ọnụ ọgụgụ nke bughi nkeji;
• N _A - ọnụ ọgụgụ nke bughi nkeji kwa 1 ahumachi nke a umi, Avogadro mgbe nile: ^6,02. October ²³ mol ^{- 1;}
• V - a mkpokọta olu nke l ma ọ bụ m ^3;
• V _m - ezengwenri olu, lita / ahumachi ma ọ bụ ^m3 / mol.

Ikpeazụ gbakọọ dị ka ndị a:

V _m = RT / P, ebe

• R - mgbe nile 8,314 J / (mol ^K.);
• T - gas okpomọkụ, K;
• P - gas mgbali Pa.

Ihe Nlereanya nke ebumnobi maka molarity na molality. ọrụ №1

Iji chọpụta ezengwenri ịta nke potassium hydroxide ngwọta na a olu nke 500 ml. The ibu Koh ngwọta bụ hà 20 grams.

definition

Ezengwenri uka nke potassium hydroxide bụ:

_Koh M = 39 + 16 + 1 = 56 g / mol.

Anyị na-atụ anya ihe potassium hydroxide na-ẹdude ke ngwọta:

ν (Koh) = m / M = 20/56 = 0,36 ahumachi.

Anyị na-echebara na olu nke ihe ngwọta na-egosi n'ụzọ dị lita:

500 ml = 500/1000 = 0,5 lita.

Kpebisie ike na ezengwenri ịta nke potassium hydroxide:

CV (Koh) = v (Koh) / V (Koh) = 0,36 / 0,5 = 0,72 mol / liter.

ọrụ №2

Gịnị sọlfọ oxide (IV) n'okpuru nkịtị ọnọdụ (i.e., mgbe P = 101325 Pa, na T = 273 K) kwesịrị iji kwadebe a sulfurous acid ngwọta na a ịta nke 2.5 mol / liter nke olu nke 5 lita?

definition

Anyị kọwaa dị ka sulfurous acid ẹdude ke ngwọta:

ν (H ₂ NKE ₃₎ = CV (H ₂ NKE ₃₎ ∙ V (ngwọta) = 2,5 ∙ 5 = 12.5 mol.

Akụkụ nnata nke sulfurous acid nwere ndị na-esonụ ụdị:

NTRE ₂ + H ₂ O = H ₂ NKE ₃

Dị ka nke a:

ν (NTRE ₂₎ = ν (H ₂ NKE _3);

ν (NTRE ₂₎ = 12.5 mol.

N'iburu n'uche na n'okpuru nkịtị ọnọdụ nke 1 ahumachi nke gas nwere a olu nke 22,4 lita, olu na-atụ nke oxide nke sọlfọ:

V (NTRE ₂₎ = ν (NTRE ₂₎ ∙ 22,4 = 12,5 ∙ 22,4 = 280 lita.

ọrụ №3

Iji chọpụta ezengwenri ịta nke NaOH na ngwọta mgbe ya ibu nta, hà 25,5%, na a njupụta nke 1.25 g / ml.

definition

Nabatara ka sample ngwọta na a olu nke 1 liter na-ekpebi ya uka:

m (ngwọta) = V (ngwọta) ∙ P (ngwọta) = 1000 ∙ 1,25 = 1,250 gram.

Anyị na-atụ anya ka ukwuu nke sample n'ọtùtù alkali:

m (NaOH) = (w ∙ m (ngwọta)) / 100% = (25,5 ∙ 1250) / 100 = 319 grams.

Ezengwenri uka nke sodium hydroxide hà:

M _NaOH = 23 + 16 + 1 = 40 g / mol.

Anyị na-atụ anya dị ka sodium hydroxide na-ẹdude ke sample:

v (NaOH) = m / M = 319/40 = 8 mol.

Kpebisie ike na ezengwenri ịta nke alkali:

CV (NaOH) = v / V = 8/1 = 8 mol / liter.

ọrụ №4

Na mmiri (100 grams) e etisasịwo 10 grams nke nnu NaCl. Nịm ịta nke ngwọta (molality).

definition

The ezengwenri uka nke NaCl bụ hà:

M _NaCl = 23 + 35 = 58 g / mol.

Number NaCl, ẹdude ke ngwọta:

ν (NaCl) = m / M = 10/58 = 0,17 ahumachi.

Na nke a, na mgbaze bụ mmiri:

100 grams nke mmiri = 100/1000 = 0,1 n'arọ H ₂ O na ngwọta.

Molal ịta nke ihe ngwọta ga-hà:

Cm (NaCl) = v (NaCl) / m (mmiri) = 0,17 / 0,1 = 1,7 mol / n'arọ.

ọrụ №5

Kpebisie ike na molal ịta nke a 15% NaOH alkali ngwọta.

definition

15% alkali ngwọta pụtara na bụla 100 grams nke ngwọta nwere 15 grams nke NaOH na 85 grams mmiri. Ma ọ bụ na ọ bụla 100 kilogram nke ngwọta nwere 15 n'arọ NaOH na 85 n'arọ mmiri. Iji kwadebe ya, ọ dị mkpa na 85 grams (kilogram) H ₂ O etisasịwo 15 grams (n'arọ) nke alkali.

Ezengwenri uka bụ sodium hydroxide:

M _NaOH = 23 + 16 + 1 = 40 g / mol.

Ugbu a anyị na-ahụ ego nke sodium hydroxide na ngwọta:

ν = m / M = 15/40 = 0.375 mol.

Ibu mgbaze (mmiri) na n'arọ:

85 grams nke H ₂ O = 85/1000 = 0.085 kg H ₂ O na ngwọta.

Mgbe nke ahụ gasịrị kpebisiri molal ịta:

Cm = (ν / m) = 0.375 / 0.085 = 4,41 mol / n'arọ.

Dị na a typical nsogbu a ga-edozi, na ọtụtụ ndị ọzọ iji chọpụta molality na molarity.