What happens to the internal energy of water vaporz2smr2sbu o27 in the air that condenses on the outside of a cold glass of water? Is work done or heat exchang2u7brssm z2o2ed? Explain.

Use the conservation of energy to explain wh )gev ie5+5cg.d.auhzy the temperature of a gas increases when it is quickly compressed — say, by puse)e.adh+5g zg.vci 5u hing down on a cylinder — whereas the temperature decreases when the gas expands.

In an isothermal process, 3700 J of work is don7pm1ve;a ws;r e by an ideal gas. Is this enough information to tell how much heat has p s;;m7ra1evwbeen added to the system? If so, how much?

Is it possible for the temperature of a system gbgu f7ae ac4p c*/;8oto remain constant even though heat flows into or o4gaucecg;o fap*/8 b7ut of it? If so, give one or two examples.

Explain why the temperature of a g/.kzpy 4 vr8mdas increases when it is adiabatically compressed. ry /kmz4v8dp.

Can mechanical energy ever be transformed complo z o(*fhq4ed6etely into heat or internal energy? Can the reverse happen? In each case, if your answer is no, explain why not; if yes, give one or two o4hdq of*z6( eexamples.

Can you warm a kitchen in winter by leavink (z+;eocjy/n k0cb4edf5 f *p;k xex8g the oven door open? Can you cool the kitchen on a hot summer day by leaving the refrigerator door open? Exp5; dj; c+eczkk/xf0f8xnyeo pe(b k*4lain.

Would a definition o 4kzqusze0s2sj 91w.nf heat engine efficiency as $e=W/Q_L$ be useful? Explain.

What plays the role of high-temperatu3uitc5 imy,ux 2d-mm1 re and low-temperature areas in (a) an internal combustion euud x mii3 tc5y2m1,-mngine, and (b) a steam engine?

Which will give the greater impr a;/:s* paykhtovement in the efficiency of a Carnot engine, a sh tkypa;*/:a10 $C^{\circ}\,$ increase in the high-temperature reservoir, or a 10 $C^{\circ}\,$ decrease in the low-temperature reservoir? Explain.

The oceans contain a tremendou8v7/ ( /l su .n-ov6fv+i u.qugqshrjds amount of thermal (internal) energy. Why, in general, is j.v-so6 7lsd vri/(q.+u gqvu/ hn8ufit not possible to put this energy to useful work?

A gas is allowed to expand (a) adiabatically and (b) isoth ,t u-r k5nov/8/7offvahw l3wermally. In each process, does the entropy increase, av5ulvh ww/k3,o o fr-fn8/t7decrease, or stay the same? Explain.

A gas can expand to twice its9;hg,srzh,n k original volume either adiabatically or isothermally. Which procez9,;srgh hn, kss would result in a greater change in entropy? Explain.

Give three examples, other than those mentioned in c 7kd cm a/w6 ej )w4c:f-ngge/vo2k2lthis Chapter, of naturally occurw nc-fk /kg2vaeocg jd:e7/wm42) cl6 ring processes in which order goes to disorder. Discuss the observability of the reverse process.

Which do you think has the greater en x 3;ky0lvh1 : kk(mun6 zuvve(s5;ddxtropy, 1 kg of solid iron or 1 kg of liquid iron? Why?k3m:ev xky6 l 5v1;hdxus n ku0vd(;(z

(a) What happens if you remove the lid of a bottle 1xo +yf21ki4tvojse(q/jl r,containing chlorine gas? (b) Does the reverse process ever happen? Why or why not? (c) Can you think of two other examples of ir4j so+q/o,1rv(2 e ktxyl1fjireversibility?

You are asked to test a machin,rdq.h gru/c5 e that the inventor calls an “in-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 that this machine cannot cool t d,5 .rhcq/urghe room?

Think up several processes (other than those al.-r fe 2n/wej.phxri)ready mentioned) that would obey the wrj/ f i2ex.pnrh)e-.first law of thermodynamics, but, if they actually occurred, would violate the second law.

Suppose a lot of papers are strewn all over the floor;duh +uo8syis2, of0ep+u ny5 i-q3r1jmtvo 3; then you stack them neatly. Does 5 ;,8n1ovooijstim3fy u-0 rh2p+eu+udsq 3ythis violate the second law of thermodynamics? Explain.

The first law of thermodynamics is sometimes whimsically stated as/ adhn/dq .b:y, “You can’t get something for nothing,” and the second law as, “You can’t even break even.” Explain how these statements coy/:hnqbd. da /uld be equivalent to the formal statements.

Entropy is often called “time’s arrow” because it tellsw2ze*9 el ka124 xpja/hmkix4n zt)g7 us in which direction natural processes occur. If a movie were run backward, n mt1pgk kw)7aexj2x44/ einl *h9azz2ame some processes that you might see that would tell you that time was “running backward.”

Living organisms, as they grow, convey01lt xk 37fntx3- whmrt relatively simple food molecules into a complex structure. Is this a violation of the second law of thermodynami0mtn3hw t yl- 7xfk31xcs?

  An ideal gas expands isothermally, peoub84hrkye h+a zaedecx:o*wc .79/*rforming $ 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 c( i2(fm3dymm e cp9s/iylinder fitted with a light frictionless piston and maintained at atmospheric pressure. When 1400 kcal of heat is added to the gas, the volume is observed to increase fp(2 9 ms/(myedici3m 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 pressure unti p k6+r4 6tx1ab:jqomil its volume is halved, and then it is allowed to expand isothermal:xj1ib4q ak+ro6t 6 pmly back to its original volume. Draw the process on a PV diagram.

Sketch a PV diagram of the following prwp14 yv;b -ntrhon6s(0mua 5tocess: 2.0 L of ideal gas at atmospheric pressure are cooled at constant pressure to a volume of 1.0 L, and then expande-v(;t rsomb5yw6t p nunah 104d 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 initially at 4.5 atm of (absolute) pressure isg t9rl u/2)pkce95ckg 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 br kcg repl gk/29uc59)tought 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 ideal gas is cut in half slowly, while beygow ezor- q5)+xk*/f m1lny 3ing kept in a container with rigid walls. In the process, 265 k*q)n+ klygm5yowof /r-x3 ez1 J 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 compretr(y4*9x7 rc2hkebmljv8-re w a1jd 2ssed adiabatically to half its volume. In doing so, 1850 J of work is d1x8jhwk-7 vjd9tl amrr(ebcy4 2re *2one 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 pr p6x+gklifqclq3; y++g9)n:ba g a*m6.e kswlessure of 3.0 atm from 400 mL to 660 mL. Heat then flows out of the gas at constant volume, and the pressure and temperature are allowed to drop unti:+ilqe6m nyl+6p3kc9 f.;gk*q gglas+bwx) al 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 anprqp1+dqa md x+ t6*9u ideal monatomic gas expand adiabatically, performing 7500 J of work in the process. What is the change in temperature of the gas during thapd*r6p x1uq+9 dm+q tis expansion?   $ K$

  Consider the followin24t oreh(e (k xgbr :7rdbk6f8g two-step process. Heat is allowed to flow out of an ideal gas at constant vol2r t7dkfg6(ohrkbxr :b8e4(eume 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 cofjug8i*. a ylmh3yl+,ntaining 1.35 moles8auh3, l j+.yf*mlyig of a monatomic 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 alongre oh-o :t);clt r1t/r the curved path in Fig. 15–24, the work doneto:e-lc1/h)rrr t;o t 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 ajv3a3ixw.lf / yqq+, frb d92state c along the curved path shown in Fig. 15–24, 80 J of heat leaves the system and 55 J 3x.rw i dq93 ja,fbaylv/f+q2of 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 instear :vwu ,j,d 8iwfyi-(ld of working 11.0 h she tookid w uw ,j(rliyf8:v,- a noontime break and ran for 1.0 h?    $ \times10^{ 7}J$

  Calculate the average metabolic rate of a per(qwy9x )(an- 7 l+v+c azrgwyrson who sleeps 8.0 h, sits at a desk 8.0 h, engages rnwy+ar+ -9(l q)yv7 x cw(zagin 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 slee7xcu qgtg2am7,; q oe1ping one hour less per day, using the time ftu7o aq;x,gm1eg2cq7 or light activity. 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 J of usefulgbo y.x-bu .o8fn*.1ol e3uz n work. What is the efficiency of thisubo.xouf83-1*. lobz . yengn engine?    %

  A heat engine does 9200 J of work per cycle while absor2- op 0mxn8 rz12*aqfi0b v+orhuooo :bing 22.0 kcal of heat from a hig xvn oo+- 0*o:hzu 8mprqobr0oaf1 i22h-temperature reservoir. What is the efficiency of this engine?    %

  What is the maximum efficiency of a heat engine whose ope bxk r ;xa5h-q0+cu)ferating temperatures arek;-c ab+h )xf5 erxq0u 580$^{\circ}\,C$ and 380$^{\circ}\,C$?   %

  The exhaust temperature of a heat engine i,l;mpq 1cl z:ws 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 its maximum theoretu msja 68n*z0mical (Carnot) efficiency 68aun0* z jmsmbetween temperatures 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 begw*ljmi4 x x8 /sf*s+c 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 nitrogeni xsl*c s4/+jm w8fgx* “fuel” (Fig. 15–25)?    %(Round to the nearest integer)

  A Carnot engine performs wo3x3w k5 dw dwu:kbj91oqx; s1krk at the rate of 440 kW while using 680 kcal of heat per second. Ixkok13wk: w5u3wdbx;q9sjd 1 f the temperature of the heat source is 570$^{\circ}\,C$, at what temperature is the waste heat exhausted?    $^{\circ}\,C$

  A Carnot engine’s openp tvlye.o4fgv *7yl5- pd)l)rating temperatures 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 of elfqzx,p8w5f. h ectric power. Estimate the heat discharged per second, assuming that the plant has an efficiency ofpf , xf.hq8zw5 38%.    $MW$

  A heat engine utilizes b5 zp*tames7 e:h c84we.u3r zy4j9pw a heat 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 exhausts its heat at rzd k6xwgs t +07,mfu2350$^{\circ}\,C$ 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 o/ j u8812wbwl.rj 6iwxg2i yqjf heat from one being theq gywj12 /l6.wjr8iwxi u8jb 2 approximate heat input of the second. 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 fgq jzpp.1(jjd: b*f /ireezer 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-freezer operates with a in xe sgu1 slpv:+p:m)l3c+f72 zi 1tnhea 24$^{\circ}\,C$ room. What is the temperature inside the freezer?    $K$

  A restaurant refrigerator has a coefficient of performance of 5.0s dii(2f twja0;un;;m. If the temperature in the kitct;(;w2mins ; jui0af dhen 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 w 4dgpxajp 2q);i*8urbjt uj6 )arm 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 wateriw x3k xltuho*5e(: 98n ff1kl 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 has an efficiency of 35%. If it were pvpibw+2) hok 1vl4v/e ossible to run it backward as a heat pump, what wpve +hik24ob) v1/l vwould be its coefficient of performance?   

  What is the change i s/7ds5u d;vdan entropy 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 heateyz;/c e tx;)ti47tford from 0$^{\circ}\,C$ to 100°C. Estimate the change in entropy of the water.    $J/K$

  What is the change in dhgzh4v18 p/1) .dfrhr kk+h oentropy 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 inb vea wa1;x-w47wenx1 itial 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 kinetica tiki; 1zu-. :nl3few energy KE just before striking the ground and coming to rest. What is the total change in entropy of the rock plus environment as izik:w3;uaflen1t -. a result of this collision?

  An aluminum rod conductsom+4 ryf8 xu2aewc/ 0m $7.50\,cal/s$ 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 3uz djw)tvdl -1z5ls syh-k -iv1 u/4n.0$^{\circ}\,C$ 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 ad-,i9ju8jl 4oz p h2ftt 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 between heat om6r8 p6goi4vmyi+ )breservoirs at 970 K and 650 K produces 55 4g6i 68+pro)movim yb0 J of work 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, of ob;ag;go5gwo/4 hy0n noyy(e78xrs l 5xtaining
(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 incqd2b 0vp2uq eqss /r8,reasing probability: (a) four aces and a king; (b) six of hearts, eight of diamonds, queen of clubs, three of hearts, jack of spades; qs,q/ub2q 02evpd rs8(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 sha0mgwdg,ag1,v-64gse0dl ooe ke six coins in your hand and drop them on the floor. Construct a table showing the eo g-vddawgmo ,16, e0gsgl40 number of microstates 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 abooegbg10 p0pe71iz)w, dy 0.lh/iid mj ut 40 W of electricity per square meter of surface area if directly facing the Sun. How large an area is requirie .g e d,idm0 01y7piwj01ol/zpb)hg ed to supply the needs 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 hi8 y(rzcd5ci1hm+ *yrnir5:d ggh 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 turn:c gy( r+1zc58iy*rrm5dhdi bines 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 artificial lake created by a dam (Fig. 6r t0uij;hix t-uj3h; 15–27). The water depth is 45 m at the dam, juxti; h630hiru j; t-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 and built an engine that )uuuol tju+xr,, alc:;+cdym4do *+eproduces 1.50 MW of usable work while taking in 3.00 MW of thermal energy at 425 K, and rejecting 1.50 MW of ty:lu ;x ,+ec ,m+djuoc+a l)ut*rd 4ouhermal 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 efficien46fgqci*hh/dz(e p( lbei7o 6cy of 0.25 and delivers 220 J of work per cycle per cylinder. When the 6qh dbzh 6*fe (4o(l7geic/piengine 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 Carnot engine) absorbs heat from thezgcbizz jl3o*m(*0 /d freezer compartment at a tempdz* mjco03zz(/ gli*berature 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 engno7yhigkg f,i9b+.) y ine 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 thg+gh7)f y.iyb ik9no, e tropics, the temperatures 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 collide andpe3q s ( ssw:lpb;x4t5 are brought ts(w x p43qb :;lts5sepo rest. Estimate the change in entropy of the universe as a result of this collision. Assume $T\,=\,20^{\circ}\,C$    $J/K$

  A 120-g insulated aluminum cup at 15 f7n d/4pm0wld$^{\circ}\,C$ 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 ofi (*qj)z3sfw v) 9bjwb performance of an ideal heat pump that extracts hfqw3)9v)*s jwj( i bbzeat 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 releas*(6iim mifr 0idkg gm/ff;6( wes 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 opers69eh7liyv5xi- vk *rating temperature $T_L\,=\,20^{\circ}\,C$ 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 giz7x4 g lq: ghhpwpo.7c 8t/+(.oypa woing from state A to state C in Fig. 15–28 for each of thpp.(8o.ig:+77x wp4h y tzcg a/wlqhoe following processes: (a) ADC, (b) ABC, and (c) AC directly.

  A 33% efficient power plant puts out 850 MW of electrical power. Coo,vfv/zt0.mgeq:ro z i(dd23lling towers are used to take away the exhaust heat. vrelt, fq3 v0gd.2z/:mid(o z
(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 steam turbines. The s ow3 rm76rt,asteam goes into the turbines superheated at 625 K and deposits itwra,m s6or 37ts unused heat in river water at 285 K. Assume that 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% effi0j 81f9;ht(flgbv1kbvt8 ayg ciency. Assume the engine’s water t8v;lb0 yghtfkgf( jvt9a1 18b emperature 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 cross-section- x gzo88 8anl3l8s)hnvcn/hbal 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 resultsdwubpb ( o53fd s,js+ tpp942f 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 conditioner keeps the temperatv:nwlant0 qjejm* ew0e: b,;4 ure 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 doo oeni6y0xdm dho:n,s;)696 cv aqqn)sr.” The humid air is pulled in by a fan and guided to a cold coil, where the temperaturensi;e) 6o6,6 :q)ncym s xdvq9oh0and 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 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