What happens to the internal energy of water vapor in the air that condenses onc jwpm7p ;7ig8yl0o3x l pcgo7py70ijmw38 x ;the outside of a cold glass of water? Is work done or heat exchanged? Explain.

Use the conservation of energy to explain why the temperature. 4ihyeo(mkt g.9b ;oa of a gas increases when it istakohg moieyb (. .49; quickly compressed — say, by pushing down on a cylinder — whereas the temperature decreases when the gas expands.

In an isothermal process, 3700 J of work is done by .dzjz dicfon56+,gf( an ideal gas. Is this enough information to tell ho.zf fc,nidgz (6+5jdow much heat has been added to the system? If so, how much?

Is it possible for the temzp-j /odf4fjt5u+x x,rvl /-z perature of a system to remain constant even though heat flows into or out of it? If so, give one or two examplj,/ xuov5rfzdtxpjl+- z4 f- /es.

Explain why the temperature of a gas increases when it is adiabatically comq2tq+ l9v4y ;o/fsaku pressetfas9u/ 4lq q ky2;v+od.

Can mechanical energy e:ctoo;q3gkbz,2et+w j, z my*wag9: z oqnx6 (ver be transformed completely into heat or internal energy? Can the reverse happen? In each case, if your answer i j 9zcyk+n, :: q(,o3mxzwgzottao2qw*e6 ;gb s no, explain why not; if yes, give one or two examples.

Can you warm a kitchen in winter by leaving the oven doorzznn c*k,.d06 :6,dk+s8uwsd puhhe r open? Can you cool the kitchen on a hot summer daukds6*ckdruzs8 ,6e z:hhp.n+n 0dw, y by leaving the refrigerator door open? Explain.

Would a definition of heat 4ols xvo- +/sxd+ox-p8:k t.i rjv)cnengine efficiency as $e=W/Q_L$ be useful? Explain.

What plays the role of high-temperature and lowwm6gpa up*sr/ fv/pu))6q 4vy3j 5 ba:f es9ra-temperature areas in (a) an internal combustion engine, and (b)vp byua4uqj rprs6s:fmv6 /ew/5 fa 3 g)p*a9) a steam engine?

Which will give the greaterv bu7e /ygvv2hsw.9w(upv3:ufxgi9 : improvement in the efficiency of a Carnot engine, a uyfs vv:g32 i/b vge w 97v(.uu:pxh9w10 $C^{\circ}\,$ increase in the high-temperature reservoir, or a 10 $C^{\circ}\,$ decrease in the low-temperature reservoir? Explain.

The oceans contain a tremendous amount of thermai86yv2c d-etkfhc3nxt9a9peq l 2 2i0l (internal) energy. Why, in general, is it no t630a9hdxq-9el28y i fnc e2i2 pctkvt possible to put this energy to useful work?

A gas is allowed to expand (a) adia zhb ;wwc1k9str+g) k:batically and (b) isothermally. In each process, does the entkg)bcrzh:s ; k+w 91twropy increase, decrease, or stay the same? Explain.

A gas can expand to twice its original volume either adiabati+qzhcps222 p0;rz nbscally or isothermally. Which process would result in h b2zcnrs+;0zq 2ps p2a greater change in entropy? Explain.

Give three examples, other than those mentid rip)toq 2+ 7np( h*v4qm3: m/m0lytksjch6 yoned in this Chapter, of naturally occurring processes in which order goes to disorder. Discu4rv6 h20tt+/3:(ym lkpmcyi )7ms*pqd jqhn oss the observability of the reverse process.

Which do you think has the greater entropy, 1 kg o,f36 la d1eyihucv9pkdqm6e uk*k f62 1(.ekrf solid iron or 1 kg of liquid k .felk(h6eur,k f*3 u126eqa ydc91mvi6dp kiron? Why?

(a) What happens if you remo td5aky3 ;/0eh ,aovnwve the lid of a bottle containing chlorine gas? (b) Does the reverse process ever happen? Why or why not? (c) Can you think of t5, /0 ynt;dahkev3oaw wo other examples of irreversibility?

You are asked to test a machine that the inventor calls an “iny25 1*o+;p colbdzy*o 7 vhmhk-room air conditioner”: a big box, standing in the middle of the room, with a cable+c*2l; 1ohoyoyd 7*vbhp zkm5 that plugs into a power outlet. When the machine is switched on, you feel a stream of cold air coming out of it. How do you know that this machine cannot cool the room?

Think up several processes (other than those already mentioned) t 7md)s z;;:; 6 zy-bvmixg5q+ vznmyxthat would obey the first law of thermodynamics, but, if they actually occurrevmy; 7mm)xz : s ynt iz+;-;5qdxv6zgbd, would violate the second law.

Suppose a lot of pap sm9g,s2bxka0iz(-mk- hb7i xers are strewn all over the floor; then you stack them neatly. Does this violate the second law of thermodynamics? Explzk,9 (- 7 s20xmkhs bgimxb-aiain.

The first law of thermodynamics is sometimes whimsically stated as, “You can’t g*jb6xsk 3cc 1ret something for nothing,” and the second law as, “You can’t even break even.” cjrb*6k c1s3xExplain how these statements could be equivalent to the formal statements.

Entropy is often called “time’s arrow” because zalaj*w sl0m s jj5 sklrb(2in*f452ya* 90stit tells us in which direction natural processes occur. If a movie were run backward, name some processesjs00barsjy*ls* a fms4 l*5lt2kn(9zwj5 a i2 that you might see that would tell you that time was “running backward.”

Living organisms, as they grow, convert rela :ar7glcdo0 nk1uu.6xtively simple food molecules into a complex structurenku.d7ga cux r0:o6l 1. Is this a violation of the second law of thermodynamics?

  An ideal gas expands isothewrb*6a4q:m +23fsn*pxq. 0cpe vfotirmally, performing $ 3.40\times10^{ 3}J$ of work in the process. Calculate
(a) the change in internal energy of the gas,
(b) the heat absorbed during this expansion.    $J$

  A gas is enclosed in a cylinder fitted with a light frictionless piston av0 8ges43 jturky;;dand maintained at atmospheric pressure. When 1400 kcal of heat is added to the gas, the volume iauvs3t jyrd;eg 48 ;0ks observed to increase slowly from $12m^3$ to $18.2m^3$ Calculate
(a) the work done by the gas .   $ \times10^{5 }$
(b) the change in internal energy of the gas.    $ \times10^{ 6}$

One liter of air is cooled at constant prdx6x t lq*xej8 7j3le8essure until its volume is halved, and then it is allowed to expand isothermally back to its orxd e x6tj xj*3e8qll78iginal volume. Draw the process on a PV diagram.

Sketch a PV diagram of the following process: 2.0 L of idealbr wn 0 b25b074ecxo9 dp ;gq+9ktvxil gas at atmospheric pressure are cooled at constant pressure to a volume of 1.0 L, an4nrw gqb x9v 2dpkx bo97it +e00lc;5bd then expanded isothermally back to 2.0 L, whereupon the pressure is increased at constant volume until the original pressure is reached.

A 1.0-L volume of air in)qw 3;1 9xezsw- eosagitially at 4.5 atm of (absolute) pressure is allowed to expand isothermally until the pressure is 1.0 atm. It is then compressed at constant pressure to its initial volume, and lastly is brought back to its original pressure by heating at constant volume. Draw the process on a PV diagram, inclueg -w)qa ssez9;1wox3 ding numbers and labels for the axes.

  The pressure in an ideal gas is cut in half slowly,y8y).- plicdi while being kept in a container with rigid walls. In the process)cipi y -y8d.l, 265 kJ of heat left the gas.
(a) How much work was done during this process?    $J$
(b) What was the change in internal energy of the gas during this process?    $kJ$

  In an engine, an almost ideal gas is compressed adiabaticbbm3k-jk2. ,wxghx6gnf+i3p w ; aop3cvr5;f ally to half its volume. In doing so, 3wk;o 3 ;pf fpvbw.jg5b3,-rg6mcxkh +xa2 in1850 J of work is done on the gas.
(a) How much heat flows into or out of the gas?    $J$
(b) What is the change in internal energy of the gas?    $J$
(c) Does its temperature rise or fall? ----待选择----fallrise 

  An ideal gas expands at a constant total pressure of 3.0 atm from 400 mL to 660 4jus* d p:ns6vmL. Heat then flows out of the gas at constant volume, and the pressure dpsu6n vjs:4* and temperature are allowed to drop until the temperature reaches its original value. Calculate
(a) the total work done by the gas in the process,   $J$
(b) the total heat flow into the gas.    $J$

  One and one-half moles of an ideal monatomic gas expand adiabatically, peju am 41 yu+fem b8czx6r504pqrforming 7500 J of work in the process. What is the change in temperatjmrc54pe0yau+81z 6u fxmq4b ure of the gas during this expansion?   $ K$

  Consider the following two-step process. Heat is allowed to flow out of an idealm( :bg)3k) 4zq)lnry+b dj ik*gvdz-t gas at constant volume so that its pres(zd+rq:zji g )g)*vkb 3y)-kd 4mntblsure drops from 2.2 atm to 1.4 atm. Then the gas expands at constant pressure, from a volume of 6.8 L to 9.3 L, where the temperature reaches its original value. See Fig. 15–22. Calculate
(a) the total work done by the gas in the process,    $J$
(b) the change in internal energy of the gas in the process,    $J$
(c) the total heat flow into or out of the gas.    $J$  ----待选择----intoout  the gas

  The PV diagram in Fig. 15–23 shows two possible states my,nv k6v 1ljskl-d4,of a system containing 1.35 moles of a monatomic ideal gask d14 smvv- l,,ykln6j.$(P_1\,=\,P_2\,=\,455N/m^2,V_1\,=\,2.00m^3,V_2\,=\,8.00m^3)$
(a) Draw the process which depicts an isobaric expansion from state 1 to state 2, and label this process A.
(b) Find the work done by the gas and the change in internal energy of the gas in process A. W =    $J$ $\Delta\,U$ =    $J$
(c) Draw the two-step process which depicts an isothermal expansion from state 1 to the volume $V_2$ followed by an isovolumetric increase in temperature to state 2, and label this process B.
(d) Find the change in internal energy of the gas for the two-step process B.    $J$

  When a gas is taken from a to c along the curved path in Fig. 15–24, the wo 6djd6oa h; -so5lw5z;pnj)5bdx xtt4 rk dona;56o - t6od)5;j5pzl jdsh d4tnxbwxe by the gas is $W\,=\,-35\,J$ and the heat added to the gas is $Q\,=\,-63\,J$ Along path abc, the work done is $W\,=\,-48\,J$
(a) What is Q for path abc?    $J$
(b) If $P_c\,=\,\frac{1}{2}P_b$ what is W for path cda?    $J$
(c) What is Q for path cda?    $J$
(d) What is $U_a-U_c$?    $J$
(e) If $U_d-U_c\,=\,5J$ what is Q for path da?    $J$

  In the process of taking a gas from state2 seber75 u+yl a to state c along the curved path shown in Fig. 15–24, 80 J of heat leaves the systeml byees7+u 52r and 55 J of work is done on the system.
(a) Determine the change in internal energy, $U_a-U_c$.    $J$
(b) When the gas is taken along the path cda, the work done by the gas is How much heat Q is added to the gas in the process cda?    $J$
(c) If $ P_a\,=\,2.5P_d$ how much work is done by the gas in the process abc?    $J$
(d) What is Q for path abc?    $J$
(e) If $U_a-U_b\,=\,10\,J$ what is Q for the process bc?    $J$
Here is a summary of what is given:
$\begin{aligned}
Q_{\mathrm{a} \rightarrow \mathrm{c}} & =-80 \mathrm{~J} \\
W_{\mathrm{a} \rightarrow \mathrm{c}} & =-55 \mathrm{~J} \\
W_{\mathrm{cda}} & =38 \mathrm{~J} \\
U_{\mathrm{a}}-U_{\mathrm{b}} & =10 \mathrm{~J} \\
P_{\mathrm{d}} & =2.5 P_{\mathrm{d}} .
\end{aligned}$

  How much energy would the perso g2.ljr degq; ,;lv/nuh( +s5gmz a)hzn of Example 15–8 transform if instead of workingrejh5 gmu;zhda2nv/l( l)gz.+ ;,gs q 11.0 h she took a noontime break and ran for 1.0 h?    $ \times10^{ 7}J$

  Calculate the average metabolic rate of a /d-c: abgrel gg31.ql person who sleeps 8.0 h, sits at a desk 8.0 h, engages in light activity 4.0 h, watcgb1-r age:/ dl glq3.ches television 2.0 h, plays tennis 1.5 h, and runs 0.5 h daily.    $W$

  A person decides to lose weight by sle yqv+4cy/zmx 1eping one hour less per day, using the time for light activity. How much weight (or mass) can this person expect to lose in 1 year, assuming no cha 1xvcm/yy4+ qznge in food intake? Assume that 1 kg of fat stores about 40,000 kJ of energy.   kg(retain one decimal places)    $lbs$

  A heat engine exhausts 8200 J of heat while performing 320008xzcnyxx5/mbae n :w o-lpc bc7p : u7b*4bg, J of useful work. What is the efficiency of this en-xbb4ux,7laz:cc 0mc:bn pw g on5b*e8/y7xpgine?    %

  A heat engine does 920 06v p9idos3 jj8md ig5bp0zn;35njar 0 J of work per cycle while absorbing 22.0 kcal of heat from a highsni308jb m6;i5j j pgovdn3z d09ar5p -temperature reservoir. What is the efficiency of this engine?    %

  What is the maximum efficiency of a heat engine whose op71 u;jmfb u/)c)g 3qqtxpj:ruerating temperatures are 5 f;)ujq :)m/xqtj17ur3gup cb80$^{\circ}\,C$ and 380$^{\circ}\,C$?   %

  The exhaust temperature of a heat engine is mtv24xs advw 6u 1bjts,13xu5 230$^{\circ}\,C$. What must be the high temperature if the Carnot efficiency is to be 28%?    $^{\circ}\,C$

  A nuclear power plant vsgiho1 ab08w7 y; vs(r zt0tgs;1f(eoperates at 75% of its maximum theoretical (Carnot) efficiency between temperatures 0rgv 0f ho;ei1a8 7((w sbtsg;ztvs1yof 625$^{\circ}\,C$ and 350$^{\circ}\,C$. If the plant produces electric energy at the rate of 1.3 GW, how much exhaust heat is discharged per hour?    $ \times10^{13 }J/h$

  It is not necessary tl( 7f9qfemnt+ hat a heat engine’s hot environment be hotter than ambient temperature. Liquid nitrogen (77 K) is about as cheap as bottled water. What would be the efficiency of an engine that made use of heat transferred from air at room temperature (293 K) to the liquid nitrogen “f7qtlfe+(mn9f uel” (Fig. 15–25)?    %(Round to the nearest integer)

  A Carnot engine performs work at the rate of 440 kW while u q+ 7mm )s2w*k/wy,w d8kuv8detjx; wjsing 680 kcal of heat per second. If the temperature of the heukvt+j*;we d , 7 jxw2swk 8/yw8mm)qdat source is 570$^{\circ}\,C$, at what temperature is the waste heat exhausted?    $^{\circ}\,C$

  A Carnot engine’s operating temprlb6bhwz*u6uh5:v /j(t phm 0eratures are 210$^{\circ}\,C$ and 45$^{\circ}\,C$. The engine’s power output is 950 W. Calculate the rate of heat output.    $W$

  A certain power plant puts out 550 MW *r ),kh uwk7h46kwife of electric power. Estimate the heat discharged per second, assuming that the plan khw*,4 ufkr7 e)wi6hkt has an efficiency of 38%.    $MW$

  A heat engine utilizes a heat m+ qorn0o-jpy)ei9 :k cko/u, source at 550$^{\circ}\,C$ and has an ideal (Carnot) efficiency of 28%. To increase the ideal efficiency to 35%, what must be the temperature of the heat source?    $^{\circ}\,C$

  A heat engine exhauskozmtr4oh-/ou(xoi 8: yfc* ya5. .u rts its heat at 350$^{\circ}\,C$ and has a Carnot efficiency of 39%. What exhaust temperature would enable it to achieve a Carnot efficiency of 49%?    $^{\circ}\,C$

  At a steam power plant, steam engines wor6ht:1hkb s864/iowng p7vxf/ ax/j upk in pairs, the output of heat from one being the approximate heat input of the sech/8n6xv k /x7f:6h4s1w b jaiogp/tupond. The operating temperatures of the first are 670$^{\circ}\,C$ and 440$^{\circ}\,C$, and of the second 430$^{\circ}\,C$ and 290$^{\circ}\,C$. If the heat of combustion of coal is $ 2.8\times10^{7 }\,J/kg$ at what rate must coal be burned if the plant is to put out 1100 MW of power? Assume the efficiency of the engines is 60% of the ideal (Carnot) efficiency.    $kg/s$

  The low temperature of a freezer cooling coil is xp/ g)chjo( b(4nioabfa1u5 3-15$^{\circ}\,C$ and the discharge temperature is 30$^{\circ}\,C$. What is the maximum theoretical coefficient of performance?   

  An ideal refrigerator-freezer operates with a in a 24w ozrld f :;2i *8wj*x*m6ytho$^{\circ}\,C$ room. What is the temperature inside the freezer?    $K$

  A restaurant refrigerator has a coefficient of performan6 bm fyq+kmg(9l*e1dc ce of 5.0. If the temperature in the k6bgyedm+ 1l *mcfqk(9itchen outside the refrigerator is 29$^{\circ}\,C$, what is the lowest temperature that could be obtained inside the refrigerator if it were ideal?    $^{\circ}\,C$

  A heat pump is used to keep a house war)4frt5s4kf h6gxu/xrr6e0 cg m at 22$^{\circ}\,C$. How much work is required of the pump to deliver 2800 J of heat into the house if the outdoor temperature is
(a) 0$^{\circ}\,C$,    $J$
(b) -15$^{\circ}\,C$ Assume ideal (Carnot) behavior.    $J$

  What volume of watera7/xkl i f v(m;onux)1 at 0$^{\circ}\,C$ can a freezer make into ice cubes in 1.0 hour, if the coefficient of performance of the cooling unit is 7.0 and the power input is 1.0 kilowatt?    $L$

  An ideal (Carnot) engine nznp ;(p /4kxor g jtnb98eop7-bn+yr9 n-fk6has an efficiency of 35%. If it were possible to run it bac 6kyg 7jo-r 9zp 8 k(rxtfnn4b-n/nbe+ n9pp;okward as a heat pump, what would be its coefficient of performance?   

  What is the change in entropy of 251qxn-2xvo r mlwttwi1.r;uz9z, ob570 g of steam at 100$^{\circ}\,C$ when it is condensed to water at 100$^{\circ}\,C$?    $J/K$

  One kilogram of water is heated fromptr cy n8,z*5;k ni,wz4uz.dl 0$^{\circ}\,C$ to 100°C. Estimate the change in entropy of the water.    $J/K$

  What is the change in entropymj4 gmqhylbo3yuvw;p5/75p +zdrg* 2 of $1\,m^3$ of water at 0$^{\circ}\,C$ when it is frozen to ice at 0$^{\circ}\,C$?   $ \times10^{6 }\, J/K $

  If $1.00\,m^3$ of water at 0$^{\circ}\,C$ is frozen and cooled to -10$^{\circ}\,C$ by being in contact with a great deal of ice at -10$^{\circ}\,C$ what would be the total change in entropy of the process?   $J/K$

  A 10.0-kg box having an initial speq/grnv d8zf) 2ed of $3.0m/s$ slides along a rough table and comes to rest. Estimate the total change in entropy of the universe. Assume all objects are at room temperature (293 K).   $J/K$

A falling rock has kinetic energy KE just beforv ,z zfasy53+;ts-pe l(v rtt)jfl5ipyu4-4he striking the ground and coming to rest. What is the total change in entropy of the rock plus environment as a result of this;azfysu p(- )4j vt3f,slr +iet5lp4yh 5 tv-z collision?

  An aluminum rod cond:*xwh hs7 e:6aqhaq. oucts $7.50\,cal/s$ from a heat source maintained at 240$^{\circ}\,C$ to a large body of water at 27$^{\circ}\,C$. Calculate the rate entropy increases per unit time in this process.   $\frac{J/K}{s}$

  1.0 kg of water at 3n 5gkryz.1,z p0$^{\circ}\,C$ is mixed with 1.0 kg of water at 60$^{\circ}\,C$ in a well-insulated container. Estimate the net change in entropy of the system.    $J/K$

  A 3.8-kg piece of alumin(7i xz28ys4ad0xth tondj1 o4um at 30$^{\circ}\,C$ is placed in 1.0 kg of water in a Styrofoam container at room temperature (20$^{\circ}\,C$). Calculate the approximate net change in entropy of the system.    $J/K$

  A real heat engine wo 0yy 5ztn/3 gqdwkgnx8ak/x19 rking between heat reservoirs at 970 K and 650 K produces 550 J of work per cycle for a heat input of 2200 J. ayzg x 910ndygn qxw/3k8t5/k
(a) Compare the efficiency of this real engine to that of an ideal (Carnot) engine.    % of ideal(Round to the nearest integer)
(b) Calculate the total entropy change of the universe per cycle of the real engine.    $J/K$
(c) Calculate the total entropy change of the universe per cycle of a Carnot engine operating between the same two temperatures.   

  Calculate the probabilities, when you throw two a1tugi.sm c+f-u/m+w m-e oq 0dice, of obtaining
(a) two numbers totaling 5. The probability is 1/  
(b) two numbers totaling 11. The probability is 1/  

Rank the following five-card hands in order of increasing probability:h nn6q 8bo0vt7 (a) four aces and a king; (b) six of hearts, eight of diamonds, queen of clubs, three of hearts, jack of spades; (c) two jacks, two que0o7vqt 6n8bn hens, and an ace; and (d) any hand having no two equal-value cards. Discuss your ranking in terms of microstates and macrostates.

  Suppose that you repeatedly shake six coins ini+v r 5gg5s+bp your hand and drop them on the floor. Construct a table showing the number of microstates that correspon5psgbrv++5i gd to each macrostate. What is the probability of obtaining
(a) three heads and three tails,   /64
(b) six heads?   /64

  Solar cells (Fig. 15–26) can pror e.axht;mzf:ec0 -ls-r6.k u duce about 40 W of electricity per square meter of surface area if directly facing the Sun. How large an area is required to supply the needs of a house tha -.rmeacefl0z -.;stkx6:uh rt requires $22k\,Wh/day$ Would this fit on the roof of an average house? (Assume the Sun shines about $9h/day$)   $m^2$

  Energy may be stored for use during peak demand by pumping waterx8hxt i fp/0x8 to a high reservoir when demand is low and then releasing it t8f0xxxpht/ 8 io drive turbines when needed. Suppose water is pumped to a lake 135 m above the turbines at a rate of $ 1.00\times10^{ 5}kg/s$ for 10.0 h at night.
(a) How much energy (kWh) is needed to do this each night?    $\times10^{9 }W\cdot\,h$
(b) If all this energy is released during a 14-h day, at 75% efficiency, what is the average power output?    kW

  Water is stored in an ard 6eubv(n,v /xtificial lake created by a dam (Fig. 15–27). The water dep6 b/dvn vu,ex(th is 45 m at the dam, and a steady flow rate of $35m^3/s$ is maintained through hydroelectric turbines installed near the base of the dam. How much electrical power can be produced?    $ \times10^{7 }W$

  An inventor claims to have designed 8qb8ufh3g8 sw(mmjva+5tyd8 and built an engine that produces 1.50 MW of usable work while taking in 3.00 MW of thermal energy at 425 K, and raw8ys db5 uq3t8hm8gj8f vm+ (ejecting 1.50 MW of thermal energy at 215 K. Is there anything fishy about his claim? Explain.  ----待选择----yesno 

  When $ 5.30\times10^{ 4}J$ of heat is added to a gas enclosed in a cylinder fitted with a light frictionless piston maintained at atmospheric pressure, the volume is observed to increase from $1.9m^3$ to $4.1m^3$ Calculate
(a) the work done by the gas,    $ \times10^{5 }J$
(b) the change in internal energy of the gas.    $ \times10^{5 }J$
(c) Graph this process on a PV diagram.

  A 4-cylinder gasoline engine has an efficiency of 0.25 and deli n,aqk3ker s1*)y+ gndvers 220 J of work per cycle per cylinder. When the engine fires at 45 cycles per sec+*,q yas1nke3gd knr)ond,
(a) what is the work done per second?    $ \times10^{4 }J/s$
(b) What is the total heat input per second from the fuel?    $ \times10^{5 }J/s$
(c) If the energy content of gasoline is 35 MJ per liter, how long does one liter last?    s

  A “Carnot” refrigerator (the f 0yoro5)9c-krn fjt2,mg n;std;z0q reverse of a Carnot engine) absorbs heat from the freezer compartment at a temperatqz- o,tc0t;09f5)kfno gnj2rr s dy ;mure of -17$^{\circ}\,C$ and exhausts it into the room at 25$^{\circ}\,C$.
(a) How much work must be done by the refrigerator to change 0.50 kg of water at 25$^{\circ}\,C$ into ice at -17$^{\circ}\,C$    $ \times10^{4 }J$
(b) If the compressor output is 210 W, what minimum time is needed to accomplish this?    s

  It has been suggested that jsdw(am)0tmxj2x2 v hl2pn8*a6f- iu a heat engine could be developed that made use of the temperature difference between water at the surface of the ocean and that several hundred meters deep. In the tropics, the temperatures may b j2l0w mau h2 xpadv28(jf)-ni*6tsmx e 27$^{\circ}\,C$ and 4$^{\circ}\,C$, respectively.
(a) What is the maximum efficiency such an engine could have?    %
(b) Why might such an engine be feasible in spite of the low efficiency?
(c) Can you imagine any adverse environmental effects that might occur?

  Two 1100-kg cars are traveling in opposite directions whey dbpt -:qq8q8n they collide and are brought to rest. Estimate the change in entropy of the universe as a resultqqqd88t -bpy: of this collision. Assume $T\,=\,20^{\circ}\,C$    $J/K$

  A 120-g insulated aluminum qgy,x;ps9zbz 23vq+1kp sc3mr(rn0fcup at 15$^{\circ}\,C$ is filled with 140 g of water at 50$^{\circ}\,C$. After a few minutes, equilibrium is reached.
(a) Determine the final temperature,    $^{\circ}\,C$
(b) estimate the total change in entropy.    $J/K$

  (a) What is the coefficient of performance of an ideal heat pump that 5tcgs5or;- 6tw q12e)ro m nidextracts heat fromnqe-i 1t5om; c6d)rtow2gr 5s 6$^{\circ}\,C$ air outside and deposits heat inside your house at 24$^{\circ}\,C$?   
(b) If this heat pump operates on 1200 W of electrical power, what is the maximum heat it can deliver into your house each hour?    $ \times10^{ 7}J$

  The burning of gasoline in as4khhg+p 3v 3ql7w)ky car releases about $ 3.0\times10^{ 4}kcal/gal$ If a car averages $41km/gal$ when driving $90km/h$ which requires 25 hp, what is the efficiency of the engine under those conditions?    %

  A Carnot engine has a lower operating tej; b g.c1i;ecfmperature $T_L\,=\,20^{\circ}\,C$ and an efficiency of 30%. By how many kelvins should the high operating temperature $T_H$ be increased to achieve an efficiency of 40%?    $K$

Calculate the work done by an ideal gas in going frt194 nutvda-j5 2fue jom state A to state C in Fig. 15–28 for each of the following dj1 t4952aj ufnvute -processes: (a) ADC, (b) ABC, and (c) AC directly.

  A 33% efficient power plant puts out 850 MW of electrical py-gk sona 7da4m*o t2 zsc(5-bower. Cooling towers a k*7dybg- aaztm - co5os(s4n2re used to take away the exhaust heat.
(a) If the air temperature is allowed to rise 7.0 $C^{\circ}\,$, estimate what volume of air $(LM^3)$ is heated per day. Will the local climate be heated significantly? $\approx$   $km^3/day$(Round to the nearest integer)
(b) If the heated air were to form a layer 200 m thick, estimate how large an area it would cover for 24 h of operation. Assume the air has density $1.2kg/m^3$ and that its specific heat is about $1.0KJ/kg\cdot\,C$ at constant pressure.    $km^2$

  Suppose a power plant delivers energy at 980 MW using s2tequtfr d8u3p6,lo4izd( 34cii 8 ghteam turbines. The steam goes into the turbines superheated at 625 K and deposits its unused heat in river water at 285 K. Assume that the turbine operates as an ide ,eucfzilp3 462h3gdtdr8q( ti4 u8oial Carnot engine.
(a) If the river flow rate is $37m^3/s$ estimate the average temperature increase of the river water immediately downstream from the power plant.    $C^{\circ} $
(b) What is the entropy increase per kilogram of the downstream river water in $J/kg \cdot\,K?$    $J/kg\cdot\,K$

  A 100-hp car engine operates at about 15% efficiency. Assume theqfbrhh( * xzg+6;0u zo engine’s water temperatu6 (q+xr*u;hzgzof h0b re of 85$^{\circ}\,C$ is its cold-temperature (exhaust) reservoir and 495$^{\circ}\,C$ is its thermal “intake” temperature (the temperature of the exploding gas–air mixture).
(a) What is the ratio of its efficiency relative to its maximum possible (Carnot) efficiency?    %
(b) Estimate how much power (in watts) goes into moving the car, and how much heat, in joules and in kcal, is exhausted to the air in 1.0 h.P =    W $Q_L$ =    $ \times10^{ 9}J$ $Q_L$ =    $ \times10^{5 }kcal$

  An ideal gas is placed in a t-1vre k wege(.8sz r 8w8.cegsall cylindrical jar of cross-sectional area $0.800m^2$ A frictionless 0.10-kg movable piston is placed vertically into the jar such that the piston’s weight is supported by the gas pressure in the jar. When the gas is heated (at constant pressure) from 25$^{\circ}\,C$ to 55$^{\circ}\,C$, the piston rises 1.0 cm. How much heat was required for this process? Assume atmospheric pressure outside.    $J$

  Metabolizing 1.0 kg of f yipva.9frg tq1+j +:o3ufub )at results in about $ 3.7\times10^{7 }J$ of internal energy in the body.
(a) In one day, how much fat does the body burn to maintain the body temperature of a person staying in bed and metabolizing at an average rate of 95 W? $\approx$ =    $kg/d$(retain two decimal places)
(b) How long would it take to burn 1.0-kg of fat this way assuming there is no food intake?    d

  An ideal air conditiog*k7lj68 0dw x,m wg in+h:fzrner keeps the temperature inside a room at 21$^{\circ}\,C$ when the outside temperature is 32$^{\circ}\,C$. If 5.3 kW of power enters a room through the windows in the form of direct radiation from the Sun, how much electrical power would be saved if the windows were shaded so that the amount of radiation were reduced to 500 W?    W

  A dehumidifier is essentially a “refrigerator with an open door.”wg : unw.wg; /fvsgk:q/ rctb( w6j qx:i5y62j The humid air is pulled in by a fan and guided to a cold coil, where the temperature is less than the dew point, and some of the air’s water condenses. After this water is extracted, the air is warmed back to its original temperature and sent into the room. In a well-designed dehumidifier, the heat is exchanged between the incoming and outgoing air. This way t6y rnq bu q:jwv 5g g6c 2twfg.ix::/kws(w/;jhe heat that is removed by the refrigerator coil mostly comes from the condensation of water vapor to liquid. Estimate how much water is removed in 1.0 h by an ideal dehumidifier, if the temperature of the room is 25$^{\circ}\,C$, the water condenses at 8$^{\circ}\,C$, and the dehumidifier does work at the rate of 600 W of electrical power.    kg