大學(xué)物理第十八單元-熱力學(xué)第一定律

1、第十八單元 熱力學(xué)第一定律課本內(nèi)容 馬文蔚，第四版，上冊 6-40典型例題例18-1一定量的某種理想氣體，開始時處于壓強、體積、溫度分別為P0=1.2×106Pa,V0=8.31×10-3m3, T0=300K的初態(tài)，后經(jīng)過一等容過程，溫度升高到T1=450K，再經(jīng)過一等溫過程，壓強降到P=PO末態(tài)，已知該理想氣體的等壓摩爾熱容與等容摩與熱容之比CP/CV=5/3。求：（1）理想氣體的等壓摩爾熱容CP和等容摩爾熱容CV 。（2）氣體從始態(tài)變到末態(tài)的全過程中從外界吸收的熱量。提示：（1）（2）例18-2一定量的剛性雙原子分子理想氣體，開始時處于壓強為p0=1.0×1

2、06Pa,體積為V0=4×10-3m3溫度為T0=300K的初態(tài)，后經(jīng)等壓膨脹過程溫度上升到T1=450K，再經(jīng)絕熱過程溫度回到T2=300K，求氣體在整過程中對外界作的功。提示： 練習(xí)十八一、選擇題：18-1有兩個相同的容器，容積固定不變，一個盛有氨氣，另一個盛有氫氣（看成剛性分子的理想氣體），它們的壓強和溫度都相等，現(xiàn)將5J的熱量傳給氫氣，使氫氣溫度升高，如果使氨氣也升高同樣的溫度，則應(yīng)向氨氣傳遞熱量是： (A) 6 J. (B) 5 J. (C) 3 J. (D) 2 J. 18-2一定量的理想氣體分別由初態(tài)a經(jīng)過程ab和由初態(tài)a經(jīng)過程acb到達相同的終態(tài)b，如pT圖所示，則兩

3、個過程中氣體從外界吸收的熱量 Q1，Q2的關(guān)系為： (A) Q1<0，Q1> Q2 (B) Q1>0，Q1> Q2 (C) Q1<0，Q1< Q2 (D) Q1>0，Q1< Q218-3對于室溫下的雙原子分子理想氣體，在等壓膨脹的情況下，系統(tǒng)對外所作的功與從外界吸收的熱量之比W / Q等于 (A) 2/3 (B) 1/2 (C) 2/5 (D) 2/7 18-41 mol理想氣體從pV圖上初態(tài)a分別經(jīng)歷如圖所示的(1) 或(2)過程到達末態(tài)b已知Ta<Tb，則這兩過程中氣體吸收的熱量Q1和Q2的關(guān)系是 (A) Q1> Q2>0

4、(B) Q2> Q1>0 (C) Q2< Q1<0 (D) Q1< Q2<0 (E) Q1= Q2>0 18-5氦氣、氮氣、水蒸汽(均視為剛性分子理想氣體)，它們的摩爾數(shù)相同，初始狀態(tài)相同，若使它們在體積不變情況下吸收相等的熱量，則 (A) 它們的溫度升高相同，壓強增加相同 (B) 它們的溫度升高相同，壓強增加不相同 (C) 它們的溫度升高不相同，壓強增加不相同 (D) 它們的溫度升高不相同，壓強增加相同 18-6一定量的理想氣體，經(jīng)歷某過程后，溫度升高了則根據(jù)熱力學(xué)定律可以斷定： (1) 該理想氣體系統(tǒng)在此過程中吸了熱 (2) 在此過程中外界對該理想

5、氣體系統(tǒng)作了正功 (3) 該理想氣體系統(tǒng)的內(nèi)能增加了 (4) 在此過程中理想氣體系統(tǒng)既從外界吸了熱，又對外作了正功 以上正確的斷言是： (A) (1)、(3) (B) (2)、(3) (C) (3) (D) (3)、(4) 提示：選C二、填空題18-7一氣缸內(nèi)貯有10 mol的單原子分子理想氣體，在壓縮過程中外界作功209J，氣體升溫1 K，此過程中氣體內(nèi)能增量為 _ ，外界傳給氣體的熱量為_ _ 18-8一定量的某種理想氣體在等壓過程中對外作功為 200 J若此種氣體為單原子分子氣體，則該過程中需吸熱_ J；若為雙原子分子氣體，則需吸熱_ J.18-92 mol單原子分子理想氣體，從平衡態(tài)1

6、經(jīng)一等體過程后達到平衡態(tài)2，溫度從 200 K上升到 500 K，若該過程為平衡過程，氣體吸收的熱量為_；若為不平衡過程，氣體吸收的熱量為_ 18-10一定量理想氣體，從A狀態(tài) (2p1，V1)經(jīng)歷如圖所示的直線過程變到B狀態(tài)(p1，2V1)，則AB過程中系統(tǒng)作功W_；內(nèi)能改變DE=_18-11常溫常壓下，一定量的某種理想氣體(其分子可視為剛性分子，自由度為i，在等壓過程中吸熱為Q，對外作功為W，內(nèi)能增加為，則 W/Q=_ _ 18-12壓強、體積和溫度都相同的氫氣和氦氣(均視為剛性分子的理想氣體)，它們的質(zhì)量之比為m1m2=_，它們的內(nèi)能之比為E1E2=_，如果它們分別在等壓過程中吸收了相同

7、的熱量，則它們對外作功之比為W1W2=_ （各量下角標(biāo)1表示氫氣，2表示氦氣） 18-13同一種理想氣體的定壓摩爾熱容Cp 大于定體摩爾熱容CV ，其原因是 _三、計算題18-14. 0.02 kg的氦氣(視為理想氣體)，溫度由17升為27若在升溫過程中，(1) 體積保持不變；(2) 壓強保持不變；(3) 不與外界交換熱量；試分別求出氣體內(nèi)能的改變、吸收的熱量、外界對氣體所作的功 18-15. 1 mol雙原子分子理想氣體從狀態(tài)A(p1,V1)沿p -V圖所示直線變化到狀態(tài)B(p2,V2)，試求： (1) 氣體的內(nèi)能增量(2) 氣體對外界所作的功 (3) 氣體吸收的熱量(4) 此過程的摩爾熱容

8、 (摩爾熱容C =Q/T，其中Q表示1 mol物質(zhì)在過程中升高溫度時所吸收的熱量)18-16. 一定量的理想氣體，由狀態(tài)a經(jīng)b到達c(如圖，abc為一直線)求此過程中 (1) 氣體對外作的功；(2) 氣體內(nèi)能的增量；(3)氣體吸收的熱量(1 atm1.013×105 Pa) 18-17.一定量的理想氣體在標(biāo)準(zhǔn)狀態(tài)下體積為 1.0×10-2 m3，求下列過程中氣體吸收的熱量（設(shè)氣體的CV = 5R / 2）： (1) 等溫膨脹到體積為 2.0×10-2 m3； (2) 先等體冷卻，再等壓膨脹到 (1) 中所到達的終態(tài) 技術(shù)官員村位于位于亞運城東部，主干道二以東石樓涌

9、以西的地塊，占地面積、m2，總建筑面積、m2，共包括地下室南區(qū)、地下室北區(qū)、地上部分1棟12棟、服務(wù)中心、室外工程等多個單體工程。其中住宅面積m2，共12棟，17棟建筑層數(shù)為11層，812棟11層（局部復(fù)式頂層），首層局部架空，布置公建配套設(shè)施。integrated energy, chemicals and textile Yibin city, are the three core pillars of the industry. In 2014, the wuliangye brand value to 73.58 billion yuan, the city's liquor

10、industry slip to stabilise. Promoting deep development of integrated energy, advanced equipment manufacturing industry, changning district, shale gas production capacity reached 277 million cubic metres, built the country's first independent high-yield wells and pipelines in the first section, t

11、he lead in factory production and supply to the population. 2.1-3 GDP growth figure 2.1-4 Yibin, Yibin city, Yibin city, fiscal revenue growth 2.1.4 topography terrain overall is Southwest, North-Eastern State. Low mountains and hills in the city landscape as the main ridge-and-Valley, pingba small

12、fragmented nature picture for "water and the second land of the seven hills". 236 meters to 2000 meters above sea level in the city, low mountain, 46.6% hills 45.3%, pingba only 8.1%. 2.1.5 development of Yibin landscapes and distinctive feature in the center of the city, with limitations,

13、 and spatial structure of typical zonal group, 2012-cities in building with an area of about 76.2km2. From city-building situation, "old town-the South Bank" Center construction is lagging behind, disintegration of the old city is slow, optimization and upgrading, quality public service re

14、sources are still heavily concentrated in the old town together. Southbank Centre has not been formed, functions of the service area space is missing. Meanwhile, peripheral group centres service was weak and inadequate accounting for city development, "suspicious" pattern could not be form

15、ed. As regards transport, with the outward expansion of cities, cities have been expanding, centripetal city traffic organization has not changed, integrated energy, chemicals and textile Yibin city, are the three core pillars of the industry. In 2014, the wuliangye brand value to 73.58 billion yuan

16、, the city's liquor industry slip to stabilise. Promoting deep development of integrated energy, advanced equipment manufacturing industry, changning district, shale gas production capacity reached 277 million cubic metres, built the country's first independent high-yield wells and pipelines

17、 in the first section, the lead in factory production and supply to the population. 2.1-3 GDP growth figure 2.1-4 Yibin, Yibin city, Yibin city, fiscal revenue growth 2.1.4 topography terrain overall is Southwest, North-Eastern State. Low mountains and hills in the city landscape as the main ridge-a

18、nd-Valley, pingba small fragmented nature picture for "water and the second land of the seven hills". 236 meters to 2000 meters above sea level in the city, low mountain, 46.6% hills 45.3%, pingba only 8.1%. 2.1.5 development of Yibin landscapes and distinctive feature in the center of the city, with limitations, and spatial structure of typical zonal group, 2012-cities in building with an area of about 76.2km2. From city-building situatio