What happens to the internal enerchg*wnoi ;54oppu8j ;gy of water vapor in the air that condenses on the outside of a cold glass of water? Is work done or 5;8* jicgp p;nh4uowo heat exchanged? Explain.

Use the conservation of energy to explain why the tempd/u1z/ r r,/q)pic dlyerature of a gas increases when it is quickly compressed — say, by pushing down on a cylinder — w,c r di /yu/)lqpz/r1dhereas the temperature decreases when the gas expands.

In an isothermal process, 3700 J of work is done by an ideal gas. Is t: u4s /ymxkbwydx0-tkwnz t*k(4/ *f1uyn m,fhis enough information to tell how much heat h ,yk0/wyn1d/*zwyk4 - t:n*mkxtxum(fb u4sf as been added to the system? If so, how much?

Is it possible for the temperas b8;pie;:.bd bmw p,zture of a system to remain constant even though heat flows into or out of it? If so, .s mez,pw8b ;pi b;:dbgive one or two examples.

Explain why the temperature of a gas increases wh4jlx-8tl +bcbe f +,yo0b1veb en it is adiabatically compress lby,t+xvece b1b8blf0 o+-4jed.

Can mechanical energy ever be transformed 7zpfbnt 1h *+xcompletely into heat or internal energy? Can the reverse happen? In each case, if your answer is no, explxh 7b1+ ptnzf*ain why not; if yes, give one or two examples.

Can you warm a kitchen in winter by leaving the oven door open? Can you coola8ivma2(:0ghx wz.4l xp2 ymf the kitchen on a hot summer day by leaving the refrigv 28f4gx mz.amx 2i(ylha0 :pwerator door open? Explain.

Would a definition of g7eoe7ks 2ed,heat engine efficiency as $e=W/Q_L$ be useful? Explain.

What plays the role of high-temperature and low-temperature areas in (a) a4ggd+tw :t1fl,belh2 n internal combustion engine, and (b) a stthlwf+b2gt 1 g eld4,:eam engine?

Which will give the greater improvement in the efficiency of a Carnot enginecbr5m.n,xy qu;; lj2v , a 1ynq.v ,u;25mcrl;xj b0 $C^{\circ}\,$ increase in the high-temperature reservoir, or a 10 $C^{\circ}\,$ decrease in the low-temperature reservoir? Explain.

The oceans contain a tremendous am on1 h w1 p:;ghf:zup0b6)xjipount of thermal (internal) energy. Why, in general, is it not possible to put thizw:p;j) pf: 0oh6ng 1b1 uxpihs energy to useful work?

A gas is allowed to expand (a) o-r5orma/b 5t)hs8v badiabatically and (b) isothermally. In each process, does the entropy increase, de5-/b )aovbs5rh8 mrot crease, or stay the same? Explain.

A gas can expand to twice its original volum jckb5 y/v*bm,e either adiabatically or isothermally. Which process would result in a greater change in entropy? Expl*m /c jybb,vk5ain.

Give three examples, other than those mentioned in this Chapter, ou-nqq;5a rw) xf naturally occurring processes in which order goes to disorder.axn )5urwq;-q Discuss the observability of the reverse process.

Which do you think has the greatfatu6i w mz (2kx;9gg0er entropy, 1 kg of solid iron or 1 kg of liquid iron? w i0g gfu ;t9kaz(62xmWhy?

(a) What happens if you remove the lid of a)hb/ynmuw* m4 bottle containing chlorine gas? (b) Does the reverse process ever happen? Why or why n4w*u )nhb/mymot? (c) Can you think of two other examples of irreversibility?

You are asked to test a machine that the inventor calls an “in:bb(iwh8m n a6-room air conditioner”: a big box, standing in the middle of the room, with a cable 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 tb :8inb(h6mwa hat this machine cannot cool the room?

Think up several processes (other than those already mentioned) that would ori)a :r 3tz2n 7ducn)ybey the first law of thermodynamics, but, if the)nnr:a)7du c 2y3i tzry actually occurred, would violate the second law.

Suppose a lot of papers are strewn all over the floor; then you stack them nj8erhc4d i5 (meatly. Does this viol5i4j(8d hec mrate the second law of thermodynamics? Explain.

The first law of thermz*.1s+8fw2cb jvpz( i3 z cwehodynamics is sometimes whimsically stated as, “You can’t get something for nothing,” and the second law as, “You can’t even break even.” Explac f82siw vw+c*z(.e 1jzbhz 3pin how these statements could be equivalent to the formal statements.

Entropy is often called “time’-(jnesz : (bevilu 8.xb6 n:d ayct2r:+b9tuxs arrow” because it tells us in which direction natural processes occur. If a movie were run backward, name some processes that you might see that wount+r9.8 tixd6:ze(c 2nxyj u b:av(b:u ls-ebld tell you that time was “running backward.”

Living organisms, as they grow, convert relatively simple food molecules into a5e s,7qtxls1( cmqbl 9 complex structure. Is this a violation of the el 1s(qbxm cq,57lt9ssecond law of thermodynamics?

  An ideal gas expands isothermally, performijkhw2*th) ljn :2zj i8ng $ 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 fittei)wh4:a xu m+w4mb u7td with a light frictionless piston and maintained at atmospheric pressure. When 1400 kcal of heat is added to tahum44tum 7):x +w ibwhe gas, the volume is 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 coiwyti:o2 l (py q 8t.0dfto9/joled at constant pressure until its volume is halved, and then it is allowed to expand isothty0 8.i(td2jw o: lqtiyfp/o9 ermally back to its original volume. Draw the process on a PV diagram.

Sketch a PV diagram of the following process: 2.0 L of ideal gas at atmosphericocn)zic1bs4 k3, hq,o pressure are cooled at constant pressure to a volume of 1.0 L, and then expanded isothermally back to 2.,occ14b,oqih n kz )s30 L, whereupon the pressure is increased at constant volume until the original pressure is reached.

A 1.0-L volume of air initially at 4.5 atm of (absolute) pressure is allowed u3zt5kps+ 4w*pq9j weto expand isothermally until the pressure is 1.3jqzt9w u wse p*k4+p50 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, including numbers and labels for the axes.

  The pressure in an ide/ba4v. .0uq+ yftwogwlvzx( my ..eype+,.om al gas is cut in half slowly, while being kept in a container with rigid walls. In the process, 265 kJ of heat left th(,. .m4a+vwo +um 0zwe.eogpvqtyy/ .. byfxle 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 adiabatically to half rjm *kf/u( .(ipcme. gbw6zp+its volume. In p*(cmk z6j gwer+(.iuf /m.pbdoing so, 1850 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 pressuzr zdh:vz8ke r)d/ (1 buayc+2re of 3.0 atm from 400 mL to 660 mL. Heat then flows out of the gas at constant volume, and the pr :zuab dh dzr8vr1c+)yzk /(2eessure 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 eeuce; v1 g)rz+jj,( epxpand adiabatically, performing 7500 J of work in the process. What is the chang);ezegp vr1uej ,(+cje in temperature of the gas during this expansion?   $ K$

  Consider the following two-step process. Heat is r 5dxi h8t),qf+t7pek allowed to flow out of an ideal gas at constant vol,kpit+8rdhq ft5e 7x) ume so that its pressure 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 of a system containing 1dobd 6- kwnck,3zt8h4.35 moles of a monato4 kzh8dnow,bk36ct -d mic ideal gas.$(P_1\,=\,P_2\,=\,455N/m^2,V_1\,=\,2.00m^3,V_2\,=\,8.00m^3)$
(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 wox6:+xz+5 zq xgx-zxrrrk do+ rx5zz6- g+xxxz:xqrne 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 state a to state c along the curv8k q7c; ie +ka1dm4lnied path shown in Fig. 15–24, 80 J of heat leavesmc+kk edn8al ;q i47i1 the system 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 person of Example 15–8 transform if instead of working:h yyev(nptcen /p/aw 4)uq*0 11pun /ye a(nq*4 / t)cyv0weph:.0 h she took a noontime break and ran for 1.0 h?    $ \times10^{ 7}J$

  Calculate the average metabolic rate of a person who sleeps 8wikdkygs qr +r 9cw )f(ct(.6).0 h, sits at a desk 8.0 h, engaggs.d69 f( q()ry)w kct+kric wes in light activity 4.0 h, watches television 2.0 h, plays tennis 1.5 h, and runs 0.5 h daily.    $W$

  A person decides to lose weight by sleeping onehkujtu6* o:j,7ld: wtaf7sinney -- 1 hour less per day, using the time for light activitt :un1 s-ei*6tyn7jjh -l ,f:wk7ouday. How much weight (or mass) can this person expect to lose in 1 year, assuming no change 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 3200 ij*lmc 1k2p b,m );zgqJ of useful work. What iqmbi2g)jcl,1;k z mp*s the efficiency of this engine?    %

  A heat engine does 9200 J of work per cycle while absorbingfg7z4s*t -q *;iyswk+f8 apit 22.0 kcal of heat from a high-temperature reservoir. What is the efficiency of this enginekfqs;w t+p7zft *i 8gs-4yai*?    %

  What is the maximum efficiency of a heat engi2-u i yva;7yv5 i.c:2 eweexcune whose operating temperatures are 580 2w yc-v;y. ve2ec:5u 7exuiia$^{\circ}\,C$ and 380$^{\circ}\,C$?   %

  The exhaust temperature of a heat engine is dy c5n2kpi y0: uc5famk1n1:a jzdf:+230$^{\circ}\,C$. What must be the high temperature if the Carnot efficiency is to be 28%?    $^{\circ}\,C$

  A nuclear power plant operates at 75% of/(4a2iiq9nea 9x goub its maximum theoretical (Carnot) efficiency between temperature qi4a(anu29o xeb9 ig/s of 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 that a heat engine’s hot environment be hotter than am t t9c;2hxqijg6q z(+tbient temperature. Liquid nitrogen (77 K) is about as cheap as bottled water. What would be thtz+ j(ti ;qcx tg2hq96e efficiency of an engine that made use of heat transferred from air at room temperature (293 K) to the liquid nitrogen “fuel” (Fig. 15–25)?    %(Round to the nearest integer)

  A Carnot engine performs c d (mbv3 vp;/5ct4pypwork at the rate of 440 kW while using 680 kcal of heat per second. If the temperature of the heat source is 57p vcptb;md v3c5y4( p/0$^{\circ}\,C$, at what temperature is the waste heat exhausted?    $^{\circ}\,C$

  A Carnot engine’s operating temperatures 2x2o3ol (gu)bc fsuc 55s4x ghare 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 MWr0nt n)q e,oy. of electric power. Estimate the heat discharged per second, assuming that the plant has an effiornqt n0y.,) eciency of 38%.    $MW$

  A heat engine utilizes a heat source at gu8 5srbzfn+7 550$^{\circ}\,C$ 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 exhausts its heat at 350p x.w0lf 34ybd 1yr04b r-;vc aut1cqv$^{\circ}\,C$ 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 work in pairs, the output of het++z4twb1 /srwfwst4at from one being the approximate heat input of the second. The operating +brw/t sfs4+w 4t1wzttemperatures 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 ofmirq ubsn*(fxx7pw;t,sec y 0dx:c1 h n)/64s a freezer cooling coil is -15$^{\circ}\,C$ and the discharge temperature is 30$^{\circ}\,C$. What is the maximum theoretical coefficient of performance?   

  An ideal refrigerator- 1:tv,e 7frhiefy1 du7i:j8loe0hg z /freezer operates with a in a 24$^{\circ}\,C$ room. What is the temperature inside the freezer?    $K$

  A restaurant refrigerator has a coeffici(6 6royw.u7f3kvtvo lr7c5 7 ayjtpb, ent of performance of 5.0. If the temperaturea766 ryf.5b kr po,7vy7wvo3ct (ulj t in the kitchen 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 warm at 22jhn;w9:e8 o0hugk2jl o81r pwl a+7k q$^{\circ}\,C$. 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 water atonobr :0*fi+ d /cid)m 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 has an efficiency of pr 2 pxwz gyw6t6om9)i3n .fq)35%. If it were possible to run it backward as a heat pump, what would be its coefficient of perfo9ptr)i2 n6o f.p ygm)qx6z3wwrmance?   

  What is the change in entr 1)0 gkno q9v4utqlox.ac3hf; opy of 250 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 lk qdu/oln7c/)-m cn3from 0$^{\circ}\,C$ to 100°C. Estimate the change in entropy of the water.    $J/K$

  What is the change in enev5,h(mkgg+dn 84oacm 4,g witropy 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 inite uf,f2dmh --prr .-dwial speed 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 before striking the ground and coming fn)0vtssb9 )zto rest. What is the sz0vs bf)n)9t total change in entropy of the rock plus environment as a result of this collision?

  An aluminum rod conductt g6b x,0qv-i/nwxa+as $7.50\,cal/s$ 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 3 (g( 2jugw 8bsaclvh+30$^{\circ}\,C$ 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 aluminum at:v e.cxtu/(cw -8klkpt +- xqz 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 working betwrlla0bg0 fz(-:ab/iboprf 94een heat reservoirs at 970 K and 650 K produces 550 J of w /009ab pf l-r gr:bial(fobz4ork per cycle for a heat input of 2200 J.
(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 dice,)+2ysr xqv 5gh 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: (a) f bpvlyq1)+e6four aces and a king; (b) six of hearts, eight of diamonds, queen of clubs, three of hearts, jack off6l)q+yb1p e v spades; (c) two jacks, two queens, 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 in your hand and drop th5ufk-c74y aclzo c.p(em on the floor. Construct a table showing the number of microsl7z c (5.c4oycu-kpaftates that correspond 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 produce about 40 W of electricir8k;c-pnpkds 1) ghw2k-d5b yty per square meter of surface area if directly facing the Sun. How large an area is required to supply the ncwksn-2 5dkp)h;8 r1-kyd gpbeeds of a house that 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 water to a hm6l qhja( w v(g5q)c7l4e7lsrav4jn0 igh reservoir when demand is low and then releasing it to drive turbines when needed. Suppose water is pumped to a lake 135 m above the turbines at a rate of 4l 6ajqa lg(sq7jcvmhe()v 0r54n7lw$ 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 artificial lake created by a dyh2 i g94jtag3am (Fig. 15–27). The water depth is 45 m at the dam, and a s2a9gj3yh tg4 iteady 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 and built an engine that prodre/s4u e,dys x z84v6euces 1.50 MW of usable work while taking in 3.00 MW of thermal energy at 425 K, and rejecting 1.50 MW of thermal energy at 215 K. Is there anything fishy about his claim? Explainue,64s8 4erzvys/xd e.  ----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 l 7u 0-:by 6r;adavohihas an efficiency of 0.25 and delivers 220 J of work per cycb0ru lovi a6yad -;h:7le per cylinder. When the engine fires at 45 cycles per second,
(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 reverse of a Cczhl8d7 t q3e/arnot engine) absorbs heat from the freezer cz/8h7dct q 3leompartment at a temperature 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 a heat engine could be developed thiqkpclv7/ d5)at made use of the temperature difference between water at the surface of the ocean and that several hundred meters deep. In the tropics, the temperatulv k7/c )qd5pires may be 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 when they coltf0wiyf9 uyi)g8 s4k-lide and are brought to rest. Estimate the change in entropy of the universe as a result of this colliskwgtufs )8iy9-f0 y4i ion. Assume $T\,=\,20^{\circ}\,C$    $J/K$

  A 120-g insulated aluminum cup at 15/ykh9 / ).v8yiie qbxzf9z, h3jjjv5t$^{\circ}\,C$ 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 coefficvwfb: 7h 64 (m/gpb3zrfrg *dfient of performance of an ideal heat pump that extracts heafvfrb3p r / gzb6d gf7h(m4:w*t from 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 a car releases abou*cphapv(c a 3 (;tsmtok6f5m-t $ 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 tempera.frqy4he/psstf 2h 3you/ig3non;ql ;h8 (;a ture $T_L\,=\,20^{\circ}\,C$ 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 from state A to state C indfl wa/ul ,.7t Fig. 15–28 for eacfwul./7 tl d,ah of the following processes: (a) ADC, (b) ABC, and (c) AC directly.

  A 33% efficient power plant s dsz 64q2)hlat7i ac5zb5n8uputs out 850 MW of electrical power. Cooling towers are used to take away the exhaust heat. nsas5 2 68tz4iz)5cuhd qal7b
(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 rhut,0x 6z keyp7rs9; 980 MW using steam turbines. The steam goes into the turbines superheated at 625 K and deposits its unused heat in river water at 285 K. Assume th7,;hut0se k xzrpr6y9at the turbine operates as an ideal 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 the engine’s wa f ao9d6,9ylw ,fl+jvcj .hu/yter tempevyjf9ly hd.u,jwo/a6 9 f+l,crature 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 tall cylindrical jar of cro igm2t6y i,acdf7b7h, ss-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 fat i8v ,v w/. cr1/tgx:vntbxnz/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 conditioner6o 5pr uoud s/9q77aqh 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 esse5 z)pt6nsy 9u/;edtinntially a “refrigerator with an open door.” 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 temperatuu/dzt9t ;6y i5n )nspere and sent into the room. In a well-designed dehumidifier, the heat is exchanged between the incoming and outgoing air. This way the 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