Entropy

Nkwupụta kpọmkwem nke iwu nke abụọ nke thermodynamics enweghị ike ịkọwa maka usoro niile a na-apụghị ịgbanwe agbanwe, yabụ anyị chọrọ nkwupụta izugbe. A na-atụ anya na nkwupụta izugbe a ga-akọwa usoro niile a na-apụghị ịgbanwe agbanwe na-eme n'eluigwe na ala. E mepụtara nkwupụta izugbe nke iwu nke abụọ nke thermodynamics n'etiti narị afọ nke iri na itoolu, site na ọnụọgụ a na-akpọ entropy (S). Clausius bu ụzọ webata Entropy ma mepụta ya site na okirikiri Carnot (injin kalori zuru oke). Dịka Clausius si kwuo, usoro na-enweta mgbanwe entropy, mgbe sistemụ ahụ nwetara okpomọkụ ọzọ (Q) na okpomọkụ na-agbanwe agbanwe, nke nha anya ya na-anọchite anya:

Δ S = Mgbanwe Entropy, Q = Okpomọkụ, T = Okpomọkụ T

Entropy bụ ọnụọgụgụ nke na-egosi ọnọdụ obere ihe dị na sistemụ ahụ nke na a pụghị ịmata ya ozugbo. Nke a na-agbakọ naanị mgbanwe entropy. Dị ka mgbanwe ike dị n'ime iwu mbụ nke thermodynamics.

Ihe Nlereanya 1:

Gas dị n'ime akpa ahụ na-agbasa n'ụzọ nkịtị. Mgbanwe dị na entropy gas bụ…

Solutions

N'oge usoro adiabatic, okpomọkụ ọ bụla na-abanye ma ọ bụ na-apụ na sistemụ (gas). Ebe ọ bụ na Q = 0 mgbe ahụ ΔS = 0. Entropy sistemụ ahụ na-adịgide adịgide. Gịnị banyere mkpakọ adiabatic? N'oge mkpakọ adiabatic, okpomọkụ ọ bụla na-abanye ma ọ bụ na-apụ na sistemụ ahụ (Q = 0). Ya mere, entropy nke sistemụ ahụ na-adịgide adịgide.

Ihe Nlereanya 2:

Injin Carnot na-amịkọrọ okpomọkụ nke 2000 J na 500 K, na-ewepụta okpomọkụ na 350 K. Gbakọọ okpomọkụ ewepụtara, na mgbanwe na entropy zuru oke maka otu okirikiri.

Solutions

T _H = 500 K

Q _H = 2000 J

T _L = 350 K

QL = _……?

Ọ bụrụ na sistemụ ahụ enweta okpomọkụ, Q ga-apụta na pozit, ọ bụrụ na sistemụ ahụ ewepụta okpomọkụ, Q ga-apụta na pozit.

N'otu okirikiri, injin Carnot na-agafe usoro isothermal abụọ a na-agbanwe agbanwe (mgbasawanye isothermal + mkpakọ isothermal) na usoro adiabatic abụọ a na-agbanwe agbanwe (mgbasawanye adiabatic na mkpakọ adiabatic). N'oge mgbasawanye na mkpakọ, ọ dịghị okpomọkụ na-abanye ma ọ bụ na-apụ na sistemụ ahụ (Q = 0). Ebe ọ bụ na Q = 0, entropy na-agbanwe n'oge usoro adiabatic = 0.

N'oge mgbasawanye nke isothermal, injin ahụ na-amịkọrọ okpomọkụ (Q) nke 2000 J na okpomọkụ (T) 500 K. Ebe ọ bụ na injin ahụ na-amịkọrọ okpomọkụ, mgbe ahụ Q dị mma. Mgbanwe nke entropy igwe n'oge mgbasawanye nke isothermal bụ:

N'oge nrụgide isothermal, injin ahụ na-ewepụta okpomọkụ (Q) ruo 1400 J na okpomọkụ nke (T) 350 K. Ebe ọ bụ na injin ahụ na-ewepụta okpomọkụ, mgbe ahụ Q na-apụta na-adịghị mma. Mgbanwe nke entropy igwe n'oge nrụgide isothermal bụ:

Mgbanwe entropy zuru oke = 4 J / K – 4 J / K = 0

Ihe Nlereanya 3:

Injin ahụ na-amịkọrọ okpomọkụ 600 J na okpomọkụ nke 300 °C, na-ewepụta okpomọkụ na okpomọkụ nke 100 °C. Na-agbakọ okpomọkụ nke ewepụtara, ma na-agbanwe entropy zuru oke maka otu okirikiri.

Solutions

T _H = 300 K

Q _H = 600 J

T _L = 100 K

QL ₌?

N'otu okirikiri, injin Carnot na-agafe usoro isothermal abụọ a na-agbanwe agbanwe (mgbasawanye isothermal + mkpakọ isothermal) na usoro adiabatic abụọ a na-agbanwe agbanwe (mkpakọ adiabatic na mgbasawanye adiabatic). N'oge mgbasawanye na mkpakọ adiabatic, okpomọkụ ọ bụla na-abanye ma ọ bụ na-apụ na sistemụ ahụ (Q = 0). N'ihi na Q = 0 mgbe ahụ entropy na-agbanwe n'oge usoro adiabatic = 0.

N'oge mgbasawanye nke isothermal, injin ahụ na-amịkọrọ okpomọkụ (Q) nke 600 J na okpomọkụ nke (T) 300 K. Ebe ọ bụ na injin ahụ na-amịkọrọ okpomọkụ, mgbe ahụ Q dị mma. Mgbanwe nke entropy igwe n'oge mgbasawanye nke isothermal bụ:

N'oge nrụgide isothermal, injin ahụ na-ewepụta okpomọkụ (Q) 200 J na okpomọkụ (T) 100 K. Ebe ọ bụ na injin ahụ na-ewepụta okpomọkụ, mgbe ahụ Q na-apụta na-adịghị mma. Mgbanwe nke entropy igwe n'oge nrụgide isothermal bụ:

Mgbanwe entropy zuru oke = 2 J / K – 2 J / K = 0

Dabere na ihe atụ nọmba 2 na ihe atụ nọmba 3, mgbanwe entropy zuru oke maka usoro a na-agbanwe agbanwe = 0. N'ime usoro a na-agbanwe agbanwe, entropy zuru oke na-agbanwe agbanwe mgbe niile.

Ọmụmaatụ 4:

Ice 2 kg na 0 °C na-amịkọrọ okpomọkụ, ya mere ọ na-agbaze. Gbakọọ mgbanwe dị na entropy ice. (Okpomọkụ nke ngwakọta maka mmiri = 3.34 x 10 ⁵ J / Kg)

Solutions

Oke ice = 2 kg

Okpomọkụ ice = 0 ^o C + 273 = 273 K

Okpomọkụ nke njikọta mmiri = 3.34 x 10 ⁵ J / Kg

Okpomọkụ dị mkpa iji gbazee kilogram 2 nke ice n'ime mmiri:

Q = ml

Q = (2 kg)(3.34 x 10 ⁵ J/Kg)

Q = 6.68 x 10 ⁵ J

Q = 668 x 10 ³ J

N'oge agbaze (ice na mmiri), okpomọkụ na-adị otu otu. Ebe ọ bụ na okpomọkụ na-adị otu otu, mgbe ahụ mgbanwe nke entropy ice bụ:

Ihe Nlereanya 5:

A na-agwakọta mmiri dị na 26°C na mmiri na 22°C. Oke mmiri ahụ bụ kilogram 2. Gbakọọ mgbanwe dị na entropy mmiri. A na-agwakọta mmiri ọkụ na mmiri oyi n'ime akpa mkpuchi nke ọma, nke mechiri emechi. Nnyefe okpomọkụ bụ usoro a na-apụghị ịgbanwe agbanwe.

Solutions

^{Okpomọkụ mmiri kpọmkwem} (c) = 4180 J/Kg C ^o

Mmiri dị n'ọbara = 2 kg

Mmiri ahụ bụ otu, ya mere okpomọkụ ikpeazụ = 24 ^o C (26 ^o C + 22 ^o C / 2 = 48 ^o C / 2 = 24 ^o C).

Oke okpomọkụ mmiri ọkụ na-ewepụta mgbe okpomọkụ ahụ belatara site na 26 °C - 24 °C bụ:

Q = mc ΔT = (2 kg) (4180 J / kg C ^o ) (26 ^o C – 24 ^o C) = (2 Kg) (4180 J / kg C ^o ) (2 ^o C) = 16720 J

Oke okpomọkụ mmiri oyi na-amịkọrọ mgbe okpomọkụ si na 22 ^oC – 24 ^oC pụta bụ:

Q = mc ΔT = (2 kg) (4180 J / kg C ^o ) (24 ^o C – 22 ^o C) = (2 kg) (4180 J / kg C ^o ) (2 ^o C) = 16720 J

Mgbanwe entropy zuru oke = mgbanwe entropy mmiri ọkụ + mgbanwe entropy mmiri oyi

Δ S = Δ S mmiri ọkụ + Δ S mmiri oyi

Δ S = Q/T + Q/T

Okpomọkụ nkezi nke mmiri ọkụ = (26 ^oC + 24 ^oC ) / 2 = 50 ^oC / 2 = 25 ^oC —- 25 + 273 = 298 K

Okpomọkụ nkezi nke mmiri oyi = (22 ^oC + 24 ^oC ) / 2 = 46 ^oC / 2 = 23 ^oC —- 23 + 273 = 296 K

Mmiri ọkụ na-ewepụta okpomọkụ, yabụ Q na-enweta adịghị mma. Mmiri oyi na-amịkọrọ okpomọkụ, yabụ Q na-enweta adịghị mma.

Δ S = Δ S mmiri ọkụ + Δ S mmiri oyi

Δ S = -Q/T + Q/T

Δ S = -16720/298 + 16720/296

Δ S = -56.107 + 56.486

Δ S = 0.379 J/K

Mkpokọta entropy mụbara site na 0.379 J/K

Ọ bụ ezie na entropy nke sistemụ ahụ na-ebelata (-56.107 J/K), entropy nke sistemụ ahụ na-abawanye n'ọtụtụ buru ibu (+ 56.486 J/K) nke mere na entropy zuru oke na-abawanye mgbe niile (+ 0.379 J/K).

Mmụba nke entropy zuru oke n'usoro a na-agbanweghi agbanwe abụghị naanị maka mbufe okpomọkụ n'etiti ngwakọta mmiri ọkụ na oyi nke a tụlere n'elu, kamakwa ọ metụtara ikpe niile ndị ọkà mmụta sayensị lere anya. Entropy zuru oke ma ọ bụrụ na usoro ahụ emee n'ụzọ a na-agbanweghi agbanwe. Ọ bụrụ na usoro ahụ emee n'ụzọ a na-agbanweghi agbanwe, entropy zuru oke na-abawanye mgbe niile.

Usoro niile sitere n'okike na ndụ anyị kwa ụbọchị enweghị ike ịgbanwe agbanwe, nke mere na entropy zuru oke ga-abawanye. A chịkọtara eziokwu a n'ahịrịokwu a:

N'ime usoro a na-apụghị ịgbanwe agbanwe, entropy zuru oke nke sistemụ na gburugburu ebe obibi na-eto mgbe niile.

Okwu a bụ nkwupụta izugbe nke iwu nke abụọ nke thermodynamics. Iwu nke abụọ nke thermodynamics dị iche na iwu anụ ahụ ndị ọzọ. Ọtụtụ mgbe, a na-egosipụta iwu nke fizik gbasara nha nhata (iwu Newton) ma ọ bụ n'ụdị iwu nke mgbe ebighị ebi (iwu nke nchekwa ike).