Which has more atoms: 1 kg of iron or 1 kg of aluminum? See the periol mu1z h fffpczyao:k2 7k*i52 gw2)6idic table or) pkf6wczal :12 kyou5i f i7z2mhg*2f Appendix B.

Name several properties of materials that could be exploited to make a t1yas9c q3j;cp: *u yxnhermometeru 1a* psq:;ccynxy93 j.

Which is larger, 1 Ck4.uxi:3 (2sm 9 8pxkwsogtr d $^{\circ} $ or 1 F $^{\circ} $?

If system A is in thermal equilibrium with system B, but B is not7 9zzks 0jzqo. in thermal equilibrium with system C, what can you say about the tempz sk9z jozq70.eratures of A, B, and C?

A flat bimetallic strip consists of alu*,ezz e;vvriqzmr 55a8g (7tvr 0lok1minum riveted to a strip of iron. When heated, the strip will bend. Which metal will be on the outside of the curve? [Hint: See Table 13–1(zer mzl*k g7zerrvv t1v 5, a0o5q;8i.] Why?

In the relation $\Delta$L = $\alpha$ $L_0$ $\Delta$T, should $L_0$ be the initial length, the final length, or does it matter? Explain.

The units for the coefficcw b(ib+cs1qm-h+x5r ient of linear expansion $\alpha$ are $(C?)^{-1}$ and there is no mention of a length unit such as meters. Would the expansion coefficient change if we used feet or millimeters instead of meters? Explain.

Figure 13–27 shows a diagram of a simple t8u2jw6xn; 1 n:wc kmnvhermostat used to control a furnace (or other heating or cooling system). The bimetallic strip consists of two strips of different metalsun:6 wncwn8 21xj; mkv bonded together. The electric switch is a glass vessel containing liquid mercury that conducts electricity when it can flow to touch both contact wires. Explain how this device controls the furnace and how it can be set at different temperatures.

Long steam pipes that are fixed at the ends often have a section in the0dq570ce x eopg9xn0p shape of a U. Why9nxq00 dc7e50xpg ope?

A flat, uniform cylinder of lead floats inp f:ajt*r (hv-v, s3kt mercury at 0 $^{\circ} $ C. Will the lead float higher or lower when the temperature is raised? Explain.

When a cold mercury-in-glass thermometer is first placed in a hot tub ky3)5 /w ry qs6i.si p/0nmqbmof water, the mercury initially descends a bit and then risem.)ibp3y 6 /i/q0m5nwsrsqk ys. Explain.

A glass container may break if one part of it is heated or cooled more rapidlyd/nxe+ 6j1 8/ rhlndzhi(z3gm than adjacen3hzzdr l 16d/mxe nng/(ihj+8t parts. Explain.

The principal virtue of Pyrex glass is that its coefficient of k8fbw.k+ xem:linear expansion is much smaller than that for ordinary glass (Table 13–1). Explain why this gives rise to the incbk8wxmf :e.+ kreased heat resistance of Pyrex.

Will a grandfather clock, accurate7r2vlk r8c ;usyf:g2w at 20 $^{\circ} $ C, run fast or slow on a hot day (30 $^{\circ} $ C)? Explain. The clock uses a pendulum supported on a long, thin brass rod.

Freezing a can of soda wilm.f) jzh,qjwtn3 nn8, z lws ()x30tb+yne .mgl cause its bottom and top to bulge so badly the can will not stand up. What has qnl8 33tmesmzn zw)g,,.jb.t+n )xnw(0jyhfhappened?

When a gas is rapidly comek8lq b ocf6s/0 -qr;qpressed (say, by pushing down a piston), its temperature increa-erqqqlc 86 ;k0sb/ foses. When a gas expands against a piston, it cools. Explain these changes in temperature using the kinetic theory, in particular noting what happens to the momentum of molecules when they strike the moving piston.

Will the buoyant force on an aluminum sphere submerged in water increase or decx1 k:z(6pykgn le/bam8-e:h krease ieg8 :lnypmx- kekkz(b:/ah 1 6f the temperature is increased from 20 $^{\circ} $ C to 40 $^{\circ} $ C?

Explain in words how Charles’s law wum t-945i,n-vg bkfvfollows from kinetic theory and the relation between average k,5- mwubk ng4i9fvt v-inetic energy and the absolute temperature.

Explain in words how Gay-Lusp2z jqdas44)6aarre +sac’s law follows from kinetic theory.

As you go higher in the Earth’s atmosphere, the ratio o-e/mlymp y6hvt eu,h: wv5 wv0gb :5*cf $N_2$ molecules to $O_2$ molecules increases. Why?

Escape velocity for the Earth refers to t7kc) rx8m -9ysjy3 juohe minimum speed an object must have to leave the Earth and never retum73ycsuj9 j-)y8xkor rn. The escape velocity for the Moon is about one-fifth what it is for the Earth due to the Moon’s smaller mass. Explain why the Moon has practically no atmosphere.

Alcohol evaporates more quickzm 5rq8:idfv83fq . fkkx*fdc-qi c*.ly than water at room temperature. What can you infer abouqcrk3d 8x:mfqvfdf.ik -qf5ic .8 *z*t the molecular properties of one relative to the other?

Explain why a hot humid day is far more uncomfortabswz ,;ouwrc/+ le than a hot dry day at the same temperatuo+ w;r,wzucs/re.

Is it possible to boil watkfkhg (pfd)0ti46qdd7on. / 0 xeg3i ger at room temperature (20 $^{\circ} $ C) without heating it? Explain.

Consider two days when kmdytrnfc , t.()sn 86cg6f8ilr ek) 8the air temperature is the same but the humidity is different. Which is more denyk, 8rcdsn6e8 k8gtlt)6ric (. fnf )mse, the dry air or the humid air at the same T? Explain.

Explain why it is dangerous to open the radiator cap of an overheated automobsxa3 (rv x,3g qu-r4rtile engrr3vgxs, -r4u t( a3qxine.

Why does exhaled air appear as a little white cloud in m0:eg,1sj(q,ivwgzt the winter (Fig. 13–28)?

  How many atoms are there in a 3.4nkx xo7) -+kivcp k o8 cxme)-(0mky)y-gram copper penny?   $ \times10^{22}$ atoms of Cu

  How does the number of atombh(z vtvj1h-*s in a 26.5-gram gold ring compare to the number in a silver r1hh*v b tj-v(zing of the same mass?$N_{Au}$ =    $N_{Ag}$

  “Room temperature” is often taken to be 68°F. What is this on the zm+w9 dv 4fr:*qi2etgCelsius scale?+ t2fm zd*9g wveiq4r:   $^{\circ} $ C
(b) The temperature of the filament in a lightbulb is about 1800 $^{\circ} $ C. What is this on the Fahrenheit scale?    $^{\circ} $ F

  Among the highest and lowest temperatures fy 25 s5bef)e;:sknlmgs oi)2recorded are 136 $^{\circ} $F in the Libyan desert and -129 $^{\circ} $F in Antarctica. What are these temperatures on the Celsius scale?high =    $^{\circ} $ C
low =    $^{\circ} $ C

  (a) 15 $^{\circ} $ below zero on the Celsius scale is what Fahrenheit temperature?    $^{\circ} $ F
(b) 15 $^{\circ} $ below zero on the Fahrenheit scale is what Celsius temperature?   $^{\circ} $ C

  In an alcohol-in-glass thek+- ov1ne:qp crmometer, the alcohol column has length 11.82 cm at 0.0 pkc1n :-oq v+e$^{\circ} $ C and length 22.85 cm at 100.0 $^{\circ} $ C. What is the temperature if the column has length
(a) 16.70 cm,    $^{\circ} $ C
(b) 20.50 cm?    $^{\circ} $ C

  A concrete highway isc7mz b seg4,k9xm3o/b built of slabs 12 m long (20 $^{\circ} $ C). How wide should the expansion cracks between the slabs be (at 20 $^{\circ} $ C) to prevent buckling if the range of temperature is -30 $^{\circ} $ C to +50 $^{\circ} $ C?    m

  Super Inva$^{TM}$, an alloy of iron and nickel, is a strong material with a very low coefficient of linear expansion [0.2$ \times10^{ -6}$(C?)$^{-1}$]
A 2.0-m-long tabletop made of this alloy is used for sensitive laser measurements where extremely high tolerances are required. How much will this table expand along its length if the temperature increases 5.0 $^{\circ} $ C? Compare to tabletops made of steel.   $ \times10^{-6 }$ m    $ \times10^{-4 }$ m

  The Eiffel Tower (Figc :q lbtj16z/iw* ajxqvpq(p0x)-vu 4. 13–29) is built of wrought iron approximately 300 m tall. Esti v0t) 1 bia(4v cpq-pz*uxq:jx6lwjq /mate how much its height changes between July (average temperature of 25°C) and January (average temperature of 2 $^{\circ} $ C). Ignore the angles of the iron beams, and treat the tower as a vertical beam.    m

  To make a secure fit, rivets that are larg3 rtfa s3k6,0to/gi7l hfd7mzer than the rivet hole are often used and the rivet is cooled (usually in dry ice) before it is placed in the hole. A steel rivet 1.871 cm in diameter is to be placed in a hole 1.869 /0fm g6if dtzs or33,l77hkatcm in diameter at 20 $^{\circ} $ C. To what temperature must the rivet be cooled if it is to fit in the hole?    $^{\circ} $ C

  The density of watere mc3:bv 2cmpc*t cfrp. e 2.)fu2z1bu at 4 $^{\circ} $ C is $ 1\times10^{3 }kg/m^3$ What is water’s density at 94 $^{\circ} $ C?    kg/$m^3$

  A quartz sphere is 8.75 cm in diameter. What will be its change in volume if (k* x*ee3;wjkd* f6fzd wca26bnkf:a it is heated f*a x6w a*ke6dc* df;ef fz2:(wj3kn kbrom 30 $^{\circ} $ C to 200 $^{\circ} $ C?    $ \times10^{ -2}cm^3$

  An ordinary glass is filled9, ;e1cohqoeee6g-3fimbfp ibolf-m 3 +5 r;d to the brim with 350.0 mL of water at 100.0$^{\circ} $ C. If the temperature decreased to 20.0 $^{\circ} $ C, how much water could be added to the glass?    mL

  It is observed that 55.50 mL ofmbbcd+1viv60 -umd* i water at 20 $^{\circ} $ C completely fills a container to the brim. When the container and the water are heated to 60 $^{\circ} $ C, 0.35 g of water is lost. (a) What is the coefficient of volume expansion of the container?    $ \times10^{-5 }$ /$C^0$(b) What is the most likely material of the container? The density of water at 60°C is 0.98324g/ml.

  (a) A brass plug is to be placed in a ring ma+8ke eor er3syo d/c+;de of iron. At 20 $^{\circ} $ C, the diameter of the plug is 8.753 cm and that of the inside of the ring is 8.743 cm. They must both be brought to what common temperature in order to fit?    $^{\circ} $ C
(b) What if the plug were iron and the ring brass?    $^{\circ} $ C

If a fluid is contained in a long, narrow vessel so it can expand rrzbe(5yht t7pid7-e 8e 8p -win essentially one direction only, show that the effective coefficient of linear expansion is approximately equal to the coefficient of vo 78 d7-yp8whe 5e-repribz t(tlume expansion $\beta$.

(a) Show that the change in dj d1m;ada5tb0 k e5, ku;5ctsthe density $\rho$ of a substance, when the temperature changes by $\Delta$T is given by $\rho$ = -$\beta$$\rho$$\Delta$T
(b) What is the fractional change in density of a lead sphere whose temperature decreases from 25 $^{\circ} $ C to -40 $^{\circ} $ C？

A uniform rectangular plate of length l and width w has coeffici4sb g4jb g)-ulo;7/pbbn:d q rent of linear expansion :gqd)-rls7j bbo; bgpbn/44u $\alpha$ Show that, if we neglect very small quantities, the change in area of the plate due to a temperature change $\Delta$T is $\Delta$A = 2$\alpha l w$$\Delta$T See Fig. 13–30.

Show that for an isotropic solid,qdg;zf+ 9da*ufg:f2 z $\beta$ = 3$\alpha$ if the amount of expansion is small. $\beta$ and $\alpha$ are the coefficients of volume and linear expansion, respectively. [Hint: Consider a cubical solid, and neglect very small quantities. See also Problem 18 and Fig. 13–30.]

  The pendulum in a grandfather clock is made o /j:mfd. 5gbe lex:gi.f brass and keeps perfect time at 17 ::5.xgmegb lf . ide/j$^{\circ} $ C. How much time is gained or lost in a year if the clock is kept at 25 $^{\circ} $ C? (Assume the frequency dependence on length for a simple pendulum applies.)$\approx$    min(Round to the nearest integer)

  (a) The tube of a mercury thermometer has an inside diameter of 0.140 mm. The .osk6ec521nz 6q1dddu(pqa a bulb has a volume of 0.2555(sncad qp6z1ddq61oe.k u a2 $cm^3$ How far will the thread of mercury move when the temperature changes from 11.5 $^{\circ} $ C to 33.0 $^{\circ} $ C? Take into account expansion of the Pyrex glass.    cm(b) Determine a formula for the length of the mercury column in terms of relevant variables. Ignore tube volume compared to bulb volume.

  A 23.4-kg solid aluminum cylindrical wheel of radius 0.415,4 bq;m:bt conf n8nn m is rotating about its axle on frictionless bearings withf 48,b5nom;ncq tn:nb angular velocity $\omega$ = 32.8 rad/s If its temperature is now raised from 20.0 $^{\circ} $ C to 75.0 $^{\circ} $ C, what is the fractional change in $\omega$?   

  An aluminum bar has the desired length4j g6ej9pvyka4 *- ,rvgwsp5g rfd0( h when at 15°C. How much stress is required to keep it at this length if the te jg5 w4*e4vg-j agr,pf6(h ykspvd r90mperature increases to 35 $^{\circ} $ C?    $ \times10^{7 }$ N/$m^2$

(a) A horizontal steel vh 6pyk m7(q4aI-beam of cross-sectional area 0.041$m^2$ is rigidly connected to two vertical steel girders. If the beam was installed when the temperature was 30$^{\circ} $ C, what stress is developed in the beam when the temperature drops to -30 $^{\circ} $ C (b) Is the ultimate strength of the steel exceeded? (c) What stress is developed if the beam is concrete and has a cross-sectional area of 0.13$m^2$ Will it fracture?

  A barrel of diameter 134.122 cm a-2 z cyukxv2,et 20$^{\circ} $ C is to be enclosed by an iron band. The circular band has an inside diameter of 134.110 cm at 20$^{\circ} $ C. It is 7.4 cm wide and 0.65 cm thick.
(a) To what temperature must the band be heated so that it will fit over the barrel? $\approx$   $^{\circ} $ C(Round to the nearest integer)
(b) What will be the tension in the band when it cools to 20$^{\circ} $ C?    N

  What are the following temperatures on eq1o)1bwka;fx w 6r4athe Kelvin scale:
(a) 86$^{\circ} $ C,    K
(b) 78$^{\circ} $F,    K
(c) -100$^{\circ} $C    K
(d) 5500°C,    K
(e) -459$^{\circ} $F    K

  Absolute zero is what temper-: q3spsi ypl.io()riature on the Fahrenheit scale?    $^{\circ} $ F

  Typical temperatures in the interior of the Earth and Sun are abrxt09y uovi1l-y e5,cik6qu 1out 4000$^{\circ} $ C and $ \times10^{6 }$ $^{\circ} $ C respectively.
(a) What are these temperatures in kelvins?    K    $ \times10^{ 6}$K
(b) What percent error is made in each case if a person forgets to change $^{\circ} $ C to K? $\approx$    %(Round to the nearest integer) $\approx$    %(Round to three decimal places)

  If 3 $m^2$ of a gas initially at STP is placed under a pressure of 3.20 atm, the temperature of the gas rises to 38.0$^{\circ} $ C. What is the volume?    $m^3$

  In an internal combustion vh(d-ozsbv8jgw l;n12,wor35x hb v)engine, air at atmospheric pressure and a temperature of abvo bswow;vzvrbd8g,-l2nh( x13 )5hj out 20$^{\circ} $C is compressed in the cylinder by a piston to $\frac{1}{9}$ of its original volume (compression ratio = 9.0). Estimate the temperature of the compressed air, assuming the pressure reaches 40 atm.    $^{\circ} $ C

  Calculate the density of oxygen at ;. yrb9 i6j(dci/fd/spbbr+b3q :mf k)t wsv- STP using the ideal gas law.    kg/$m^3$

  A storage tank contains 21.6 kg of nitrogen (0:k/mxf6 2i vaggv1g 0zri:* aua dsb6$N_2$) at an absolute pressure of 3.65 atm. What will the pressure be if the nitrogen is replaced by an equal mass of $CO_2$    atm

  A storage tank at STP contains 18.5 kg of nitrogx yqb3y * +khb6g1alp70l0a gn/ua7nden ($N_2$)
(a) What is the volume of the tank? $\approx$   $m^3$(“Round to one decimal places)
(b) What is the pressure if an additional 15.0 kg of nitrogen is added without changing the temperature?    $ \times10^{5 }$Pa    atm

  If 18.75 mol of helium gas is* kl*vc69mhzh,(bae*cm) tq e at 10.0$^{\circ} $C and a gauge pressure of 0.350 atm, (a) calculate the volume of the helium gas under these conditions.    $m^3$
(b) Calculate the temperature if the gas is compressed to precisely half the volume at a gauge pressure of 1.00 atm.    $^{\circ} $ C

  What is the pressure inside a 35.0-L container ho-tonucfy 30a1si pvy 5q4;t l:lding 105.0 kg of argon gas at 385 K -t:silfcptvy04; 1ny5 3ao qu?   $ \times10^{ 8}$Pa

  A tank contains 26.0 kg o8 cg) dribyhs - ivmx43,n/h4jf $O_2$ gas at a gauge pressure of 8.70 atm. If the oxygen is replaced by helium, how many kilograms of the latter will be needed to produce a gauge pressure of 7.00 atm?    kg He

  A hot-air balloon achieve8j,wh;l65ro3hy fe j 3toxj.o*b c7kd s its buoyant lift by heating the air inside the balloon, which makes it lj86cdwjhoyf 3 t rb jex3l ho;,*7ok.5ess dense than the air outside. Suppose the volume of a balloon is 1800 $m^3$ and the required lift is 2700 N (rough estimate of the weight of the equipment and passenger). Calculate the temperature of the air inside the balloon which will produce the required lift. Assume that the outside air temperature is 0 $^{\circ} $ C and that air is an ideal gas under these conditions. What factors limit the maximum altitude attainable by this method for a given load? (Neglect variables like wind.) $\approx$    $^{\circ} $ C(Round to the nearest integer)

  A tire is filled with air)8*lrqg k/(z3v; mxf bdov3vl at 15 $^{\circ} $ C to a gauge pressure of 220 kPa. If the tire reaches a temperature of 38 $^{\circ} $ C, what fraction of the original air must be removed if the original pressure of 220 kPa is to be maintained?    %

  If 61.5 L of oxygen at p xh df//uov(e.,lxvq8vxv5rn 7q m5118.0 $^{\circ} $ C and an absolute pressure of 2.45 atm are compressed to 48.8 L and at the same time the temperature is raised to 50.0°C, what will the new pressure be?    atm

  A helium-filled balloon escapes a child’s hand at s)wquhstl* 7. vea level and 20.0 $^{\circ} $ C. When it reaches an altitude of 3000 m, where the temperature is 5.0 $^{\circ} $ C and the pressure is only 0.70 atm, how will its volume compare to that at sea level?    times the original volume

  Calculate the number of molecules / 9vwx+outr1ac15 1td h$m^3$ in an ideal gas at STP.    $ \times10^{25 }$ molecules /$m^3$

  How many moles of water are there in 1.000 L? How many molecvu/9dz 6b :zoeules?    mol    $ \times10^{25 }$ molecules

  Estimate the number x4l hc*x fh9e;bm0fm(of (a) moles,    $ \times10^{22 }$ moles and (b) molecules of water in all the Earth’s oceans. Assume water covers 75% of the Earth to an average depth of 3 km. $\approx$    $ \times10^{46 }$ molecules

  A cubic box of volum c73 iv)r:ovpdc(-e .gcxpd+ne 5.1$ \times10^{ -2}m^3$ is filled with air at atmospheric pressure at 20 $^{\circ} $ C. The box is closed and heated to 180 $^{\circ} $ C. What is the net force on each side of the box?    N

  Estimate how many molecules of air are in each g yhj 7ysp11*p /3wdwt2.0-L breath you inhale that were also in the last breath Galileo jt y31wp7w*/s1ydpgh took. [Hint: Assume the atmosphere is about 10 km high and of constant density.]   $\frac{molecules}{breath}$

  (a) What is the average translational kinetic energy of an9 sxthrl+zl, ,fuh:u5hedmc)/2 j3s z oxygen molecule at STfj9,/3t :,d2)lus 5esz hlmuc+x zhhr P?    $ \times10^{-21 }$ J
(b) What is the total translational kinetic energy of 2.0 mol of $O_2$ molecules at 20 $^{\circ} $ C?   $ \times10^{3 }$ J

  Calculate the rms speed of helium atoms near the surface of n 6nus39oo/ 0nvd h.v6o7df*y8 cnqgmthe Sun at a temperature of about 6000 K. nqs63 .o9v6udno nvyd/fg * omn h087c   m/s

  By what factor will the rms speed of gas molecules increase if the temperatujy/ ei ,(1xmml u.j6mzre iszux,y(mj6i. em/m jl 1 increased from 0 $^{\circ} $ C to 100 $^{\circ} $ C?   

  A gas is at 20 $^{\circ} $ C. To what temperature must it be raised to double the rms speed of its molecules?    $^{\circ} $ C

  Twelve molecules have the follz p3e gjz422zjowing speeds, given in units of km/s: 6, 2, 4, 6, 0, 4, 1, 8,42j3 zezgj pz2 5, 3, 7, and 8. Calculate the rms speed. $v_{rms}$ =    km/s

  The rms speed of molecules in a gas at 20- 7jga; w qg:lxjvo51i.0 $^{\circ} $ C is to be increased by 1.0%. To what temperature must it be raised?    $^{\circ} $ C

  If the pressure of a gas is doubled while its volume is held cp5/yisy:v-il hw* m / ctnhu2)onstant, by what fpl /m)2/tyicw 5h*vn yh :usi-actor does $v_{rms}$ change?   

Show that the rms speed j/; huzib+i.f+3atj r of molecules in a gas is given by $v_{rms}$ = $\sqrt{3P\\rho}$ where P is the pressure in the gas, and $\rho$ is the gas density.

Show that for a mixture of two gases at the same temperature, ny uxh2nn/h90 l (o6b4)hej,eil)hd y the ratio of their rms speeds is equal to the inverse ratio of the square roots of their moleco)lu9idl)/ejnh2 (4hbn nx yeh0,6y h ular masses.

  What is the rms speed of nitrogen mox-di wh3f6j z8lecules contained in an 8.5$-m^3$ volume at 2.1 atm if the total amount of nitrogen is 1300 mol?    m/s

  Calculate (a) the rms speed of an oxygeqq 2h.wa7vqv 6n molecule at 0 $^{\circ} $ C    m/s
(b) determine how many times per second it would move back and forth across a 7.0-m-long room on the average, assuming it made very few collisions with other molecules.    round trips per sec

  What is the average distanc6 u:ve .0fuwxdmjyr9/* eaf o+e between nitrogen molecules at STP?    $ \times10^{-9 }$m

  (a) Estimate the rms speed of an amino acid whose molecular mass is 89 ug9a )k-o, 5ub s(p5fkjyi(d js in a livinf(bkdy(kj i j,)p59ag5us so -g cell at 37 $^{\circ} $ C.    m/s
(b) What would be the rms speed of a protein of molecular mass 50,000 u at 37 $^{\circ} $ C?    m/s

Show that the pressure P of a gas can be woz.qvs ey6q;q8v 1kl6b v;h. nritten P = $\frac(1)(3)\rho v^2$ where $\rho$ is the density of the gas and v is the rms speed of the molecules.

  The two isotopes of u; .b4; j/)s*wdsdvfipv ytvh a2h1q9uranium, $^{235}$U and $^{238}$U (the superscripts refer to their atomic mass), can be separated by a gas-diffusion process by combining them with fluorine to make the gaseous compound UF$_6$ Calculate the ratio of the rms speeds of these molecules for the two isotopes, at constant T.   

(a) At atmospheric presspzvpt(fd5 - 1dure, in what phases can $CO_2$ exist? (b) For what range of pressures and temperatures can $CO_2$ be a liquid? Refer to Fig. 13–21.

Water is in which phase when the phr5edb 50llq4+8zy . d:+gaw xte) uabressure is 0.01 atm and the temperature is (a) 9+)ty.h5+ e 4d0lqe:l xbgub5adw 8 arz0 $^{\circ} $ C, (b) -20 $^{\circ} $ C.

  What is the dew point (approximately) if the humidity is 50% on a datb2i )e v*e3noy when the tn3o )ei2btve*emperature is 25 $^{\circ} $ C?$\approx$    $^{\circ} $ C(Round to the nearest integer)

  What is the air pressure at a place where water boils at 9mz481p nwpw (2 4poubj0 $^{\circ} $ C?    torr    Pa    atm

  If the air pressure at a particular place in the2zn asj/ 87eie3p5ie2li 3d wu n.*tuj mountains is 0.72 atm, estimate the temperature at ej 3iz n5*2ulea78 2eni/.jpsud w3t iwhich water boils. $\approx$ =    $^{\circ} $ C

  What is the temperatu,yycuwcg1 bxw8g 7j0gk)8b5b re on a day when the partial pressure of water is 530 Pa and the relative humidit8gj) bw8c 0yb7uw,bc ky5xgg1y is 40%? $\approx$ =    $^{\circ} $ C(Round to the nearest integer)

  What is the partial pressure of water on a day when the temjsy4 h93u4bvly(m/h u perature is 25 $^{\circ} $ C and the relative humidity is 35%?    Pa

  What is the approximate pressure inside a pressure cooke6pnu5e mkzqrb (n,iyz./c2h 2r if the water is boiling at a tempkynq/ 6z2n 5 eihr(z2p,bcmu.erature of 120 $^{\circ} $ C? Assume no air escaped during the heating process, which started at 20 $^{\circ} $ C.    atm

  If the humidity in a room ofn7t-spoa x2g xrs ;a 60qib-i) volume 680$m^3$ at 25 $^{\circ} $ C is 80%, what mass of water can still evaporate from an open pan?    kg

  Air that is at its dew poin wt 3np;p0(4fl5ok knht of 5 $^{\circ} $ C is drawn into a building where it is heated to 25. What will be the relative humidity at this temperature? Assume constant pressure of 1.0 atm. Take into account the expansion of the air.    %

  Estimate the time needed fbzi-kuh*t y-4-e imd 3or a glycine molecule (see Table 13–4) to diffuse a distance oui mhzdt-4 i-k*e-3 byf 15 $\mu m$ in water at 20$^{\circ} $ C if its concentration varies over that distance from 1 mol/$m^3$ to 0.4 mol/$m^3$ Compare this “speed” to its rms (thermal) speed. The molecular mass of glycine is about 75 u. t $\approx$    s ([color=rgba(0, 0, 0, 0.85)]Round to one decimal places) $v_{diffuse}$    $ \times10^{ -5}$ m/s
$v_{rms}$    m/s

  Oxygen diffuses from the surface of insehtc/ mc9)r b.2 h;rzxects to the interior through tiny tubes called tracheae. An average trachea is about 2 mm long and has cross-sectional arebxc r)r/zhm 29ehtc ;.a of $ 2\times10^{-9 } m^2$ Assuming the concentration of oxygen inside is half what it is outside in the atmosphere,
(a) show that the concentration of oxygen in the air (assume 21% is oxygen) at 20$^{\circ} $ C is about 8.7 mol/$m^3$ then $\approx$    mol/$m^3$(Round to one decimal places)
(b) calculate the diffusion rate J,    $ \times10^{-11 }$ mol/s
(c) estimate the average time for a molecule to diffuse in. Assume the diffusion constant is $ 1\times10^{-5 } m^2/s$    s

  A precise steel tape measure has-q iqc a/pllo5m53p)k been calibrated at 20$^{\circ} $C. At 34$^{\circ} $C,
(a) will it read high or low,
(b) what will be the percentage error?    $ \times10^{-4 }$ %

  A precise steel tape meas j*r-)f k75o a6rju.znut/v z .kvyd3mure has been calibrated at 20$^{\circ} $C. At 34$^{\circ} $C,
(a) will it read high or low,
(b) what will be the percentage error?    $ \times10^{-4 }$ %

  A Pyrex measuring cup was calibrated at normal rpx8dm8vm ;b8 woom temperature. How much error will be made in a mv88dw8p;bmx recipe calling for 300 mL of cool water, if the water and the cup are hot, at 80$^{\circ} $C, instead of at 20$^{\circ} $C? Neglect the glass expansion.$\approx$    ml

  The gauge pressure in a heliu;*c4 y hbdp4rum gas cylinder is initially 28 atm. After many balloons have been blown up, the gauge p uh4*y rp;bdc4ressure has decreased to 5 atm. What fraction of the original gas remains in the cylinder?   

  Estimate the number of air molecules in a room of length 6.5 m, width 3.1 m, aniw4bs ,o0x6w ; sy*gzud height 2.5 m0w us y;,igszb4ow*x6. Assume the temperature is 22$^{\circ} $C. How many moles does that correspond to?    $\times10^{27 }$ molecules    moles

  In outer space the density of matter is s4vl-6w8 6tnmce9uzlz n1w jmk t 85l(about one atom per $cm^3$ mainly hydrogen atoms, and the temperature is about 2.7 K. Calculate the rms speed of these hydrogen atoms, and the pressure (in atmospheres).$v_{rms}$ =    m/s    $ \times10^{-22 }$ atm

  The lowest pressure attainable using the best ac09ynr e-fxk*jbrf ,1 vailable vacuum techniques is aboutx-yjb*1renff , 0ck9 r $10^{-12} N/m^2$ At such a pressure, how many molecules are there per $cm^3$ at 0$^{\circ} $C?    $\frac{molecules}{cm^3}$

  If a scuba diver fills his lungs to full capacity of 5.5k3b i(t pb7v791f gr ,be.okqy L when 10 m below the surface, to what volbif,ro 9 7eyk q k73b1tvpg(.bume would his lungs expand if he quickly rose to the surface? Is this advisable?    L

  A space vehicle returning from the Moon enters ae m4g4v4 xn6pqtr--gqkr a86Earth’s atmosphere at a speed of about 40,000 km/h Molecules (assume nitrogen) strikgv4xqq6k68e rag-apr 4 -4nmting the nose of the vehicle with this speed correspond to what temperature? (Because of this high temperature, the nose of a space vehicle must be made of special materials; indeed, part of it does vaporize, and this is seen as a bright blaze upon reentry.)    K

  The temperature of an ideal gas is increass- j+d6y6f- oi/bifwc3rxh3 r ed from 110$^{\circ} $C to 360$^{\circ} $C while the volume and the number of moles stay constant. By what factor does the pressure change? By what factor does $v_{rms}$ change?$\frac{P_2}{P_1}$ =    $\frac{(v_{rms})_2}{(v_{rms})_1}$ =   

  A house has a volume of5bnv-mh5 ohrz 72f,et 770m$^2$ (a) What is the total mass of air inside the house at 20$^{\circ} $C?    kg
(b) If the temperature drops to -10$^{\circ} $C what mass of air enters or leaves the house?    kg

  From the known value z*xbj w8yb6 lu0fk-z *:3uibzlo.5 wuof atmospheric pressure at the surface of the Earth, estimate the total numk. 5w 0 yzubu* lbbj6 woiuxfz3:zl-8*ber of air molecules in the Earth’s atmosphere.    $ \times10^{44 }$ molecules

  What is the rms speed of nitrogen molecules contained in a ,ttl, 20djbuf7.6$-m^3$ volume at 4.2 atm if the total amount of nitrogen is 1800 mol?    m/s

  A standard cylinder of oxygen used in a hospital has gau jf7 fs4kd*w;dge pressure = 2000 psi (13,800 kPa) and at T = 259K How long will the cylinder last if the flow rate, measured at atmospheric pressure, is constant at 2.4 L/min.ks7;fj d*wf 4d $\approx$    hour

  An iron cube floats in a bowl of liquid mercurym2p6lhh*55vty ,an jq at 0$^{\circ} $C. (a) If the temperature is raised to 25$^{\circ} $C, will the cube float higher or lower in the mercury? ----待选择----lowerheigher 
(b) By what percent will the fraction of volume submerged change?    %

  The density of gasoline as/nbk-txa-h 1y+y1v4qe0px r t 0$^{\circ} $C is 0.68$ \times10^{3 }kg/m^3$ What is the density on a hot day, when the temperature is 38$^{\circ} $C?    kg/$m^3$
What is the percentage change?    %

  If a steel band were to fit snugly around the Earth’s equ ox)uman1*;m uator at 25$^{\circ} $C, but then was heated to 45$^{\circ} $C, how high above the Earth would the band be (assume equal everywhere)?    m

  A brass lid screws tightly onto a gol.*/ws8mf w glass jar at 20$^{\circ} $C. To help open the jar, it can be placed into a bath of hot water. After this treatment, the temperatures of the lid and the jar are both 60$^{\circ} $C. The inside diameter of the lid is 8.0 cm at 20$^{\circ} $C. Find the size of the gap (difference in radius) that develops by this procedure.    cm

  The first length standard, aq y.v9y*phck lv-n57x dopted in the 18$^{th}$ century, was a platinum bar with two very fine marks separated by what was defined to be exactly 1 m. If this standard bar was to be accurate to within $\pm1.0 \mu m$ how carefully would the trustees have needed to control the temperature? The coefficient of linear expansion for platinum is $ 9\times10^{ -6}C/^{-1}$. $\pm$ =    C$^{\circ} $

  A scuba tank, when fully -w plr4 bor -3a7td,i)9hiqgcs6xd1 wcharged, has a pressure of 195 atm at 20$^{\circ} $C. The volume of the tank is 11.3 L.
(a) What would the volume of the air be at 1.00 atm and at the same temperature?    L
(b) Before entering the water, a person consumes 2.0 L of air in each breath, and breathes 12 times a minute. At this rate, how long would the tank last?    min
(c) At a depth of 20.0 m of sea water and temperature of 10$^{\circ} $C, how long would the same tank last assuming the breathing rate does not change?    min

  The escape speed from the Earth isjhc g;5 sso4-r $ 1.12\times10^{4 } m/s$ so a gas molecule travelling away from Earth near the outer boundary of the Earth’s atmosphere would, at this speed, be able to escape from the Earth’s gravitational field. At what temperature is the average speed of
(a) oxygen molecules,    $ \times10^{5 }$K
(b) helium atoms equal to $ 1.12\times10^{4 } m/s$    $ \times10^{4}$K
(c) Can you see why our atmosphere contains oxygen but not helium?

  A 1.0-kg trash-can lid is suspended against gravity by tennis balls thrrfcu;1m 8 z7zuown vertically upward at it. How many tennis balls per second furc87;1zuzm must rebound from the lid elastically, assuming they have a mass of 0.060 kg and are thrown at 12m/s   balls/s

  A scuba diver releases a 36 q . 0luynof3x)7krm4/cmsau.00-cm-diameter (spherical) bubble of air from a depth of 14.0 m in a lake. Assume the temperature is constant at 298 K, and the air behaves as a perfect gas. How large is the bubble when it reaches the surface?n/ .qru7xk36am0l )ouyscfm 4    cm

  Calculate the total wateruiah*p74x,/25xuncj )o5 p8nrqtt iv vapor pressure in the air on the following two days: nip) 5q 75hor ujncavxtux8/ t2p,4*i
(a) a hot summer day, with the temperature 30$^{\circ} $C and the relative humidity at 40%;    Pa
(b) a cold winter day, with the temperature 5$^{\circ} $C and the relative humidity at 80%.    Pa

  A sauna has 7$m^3$ of air volume, and the temperature is 90$^{\circ} $C. The air is perfectly dry. How much water (in kg) should be evaporated if we want to increase the relative humidity from 0% to 10%? (See Table 13–3.)    kg

  Estimate the percent difference in the density of iron at ST7ut 90ww/sxuoP, and when it is a solid deep in u79tw/s xowu0 the Earth where the temperature is 2000$^{\circ} $C and under 5000 atm of pressure. Assume the bulk modulus (90$\times 10^9N/m^2$) and the coefficient of volume expansion do not vary with temperature and are the same as at STP.    %  ----待选择----decreaseincrease 

(a) Use the ideal gas (3 r fpnhcey+/law to show that, for an ideal gas at constant pressure, the coefficient of volume expansion is ereyhc(+nf/ 3pqual to $\beta$ = 1/T where T is the temperature in kelvins. Compare to Table 13–1 for gases at T = 293K (b) Show that the bulk modulus (Section 9–5) for an ideal gas held at constant temperature is B = P where P is the pressure.

  In humid climates, people constantly dehumidify their cellb a6(z,q6jw-ezuj(/s k 5yhqoars to prevent rot and/bh (s,q-eyqkj5zj (6wuz 6oa mildew. If the cellar in a house (kept at 20$^{\circ} $C) has 95 $m^2$ of floor space and a ceiling height of 2.8 m, what is the mass of water that must be removed from it to drop the humidity from 95% to a more reasonable 30%?    kg