Which has more atoms: 1 kg of iron or 1 kg of aluminum? See the periodii tsbt. 2v.6xn/hn utj io* krd)d tq17xm,/p2c table or Appendixq) /dstunv.t2n7 i mp*.rx/,dkih6x1oj tb2t B.

Name several properties of m*8aiswhf(i*ey+b0 lrw zo7 9 raterials that could be exploited to make a thermomete o9i+bfwri0za* y (w7 h*le8rsr.

Which is larger, 1 C +h-*o-hpqlu.mr w 0wj$^{\circ} $ or 1 F $^{\circ} $?

If system A is in thermal equilibrium with system B, but B is not in thermal equ5z4 o29xybxz jilibrium with system C, what can you say about the temperatures x25o y49j zxbzof A, B, and C?

A flat bimetallic strip consists of alumisb.-u 7v-uhlcnum riveted to a strip of iron. When heated, the strip will bend. Which metal will be on the outside of the curve? [Hint:s-h b ulc7v.u- See Table 13–1.] 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 coefficient of 2lq6vv t4.wqf 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 thermostat used to contr ;dwak6 1bhk7-oe,v jiol a furnace (or other heating or cooling system). The bimetallic strip consists of two strips of different metals bonded together. The electric switch is a glass vessel containing liquid mercury that conducts electricity when it can flow to to,jk1 bh7a d ;ikw6-veouch 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 ggb,bw 0xqu+ya/g+5men *31r 2 yv mznsection in the shape of 3ygvq,e+w2a5gm+ nr mgxb 0un1z by*/a U. Why?

A flat, uniform cylinder of lead floats in mercury at /;,bvvwlxhz9zf /mf ; 0 $^{\circ} $ C. Will the lead float higher or lower when the temperature is raised? Explain.

When a cold mercury-in h qpn8 7:8mujlml*-sc ojdp9;tk nv)9-glass thermometer is first placed in a hot tub of water, the mercury initially descends a bit and then rises.cn97;j u*khjp8 tllov:9)dnmqm 8 -sp Explain.

A glass container may break if iqyp8k mkh5ywd7q2yn0,( t 7gone part of it is heated or cooled more rapidly than adg8kqth wmiyp 7(d5kq2y0 ,y n7jacent parts. Explain.

The principal virtue of Pyrex glass is that its coefficient of li05ld(caax*x 4* r0 h wfeg3meknear expansion is much smaller than that for ordinary glass (Table 13–1). Explain why thfxkd00a(* *3exw c a5hrlg4em is gives rise to the increased heat resistance of Pyrex.

Will a grandfather clock, accurate ath,4o.h,tzqw v48nhq j 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 will cause its bottom and top to bulge so badly theyrwfi1+ p9gyb1,a ig2/ugn4y can will not stand up. What has ha1n2yyf+a yrgubg 9w/p1 i i4g,ppened?

When a gas is rapidly compressed (say.** wtitslnegv mm d+9*c+2anifo29 l, by pushing down a piston), its temperature increases. 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 thenmlm.9w+ *s9ctlt2n io** +eg2d aivf moving piston.

Will the buoyant force on an aluminum sphere submerged in :z aul9jww v2o-+ ii9fusa1-d water increase or decrease if the temperatu+-zui2-ajdsl9owi19v f : auw re is increased from 20 $^{\circ} $ C to 40 $^{\circ} $ C?

Explain in words how Charles’s law follows from kinetic theory and the relatiog,ah ,(vg( f: ydhp9v6db(iion between averag y(dghdvia( vihbpg96,o f(, :e kinetic energy and the absolute temperature.

Explain in words how Gay-Lussac’s law follows from ki9hxuu w1t y1f/netic theory.

As you go higher in the Earth’s atmos/qa6ixlr s+: k8(o)jjxjqijm59qol ;xt/9exphere, the ratio of $N_2$ molecules to $O_2$ molecules increases. Why?

Escape velocity for the Earth refers to the minimznkb dtxx)q*.i q7*3 e wdk6.sum speed an object must have to leave the Earth and never return. The escape velocity for the Moon is about one-fifth what it is for the Earth d xz6.*ike t.sqd 3dknx*w) qb7ue to the Moon’s smaller mass. Explain why the Moon has practically no atmosphere.

Alcohol evaporates more quickly than water at room tempera f9zi)rst/dv k ,4y7ost-mt 2vture. What can you infer about the molecular properties of one relative to v,4ts2vi7zd m9-)sttyf k/orthe other?

Explain why a hot humid day is far more uncdw .v9r;qsko 1z.ffy(m(5xxmacw:ro s ,y .d,omfortable than a hot dry day at the same temperaturz9qrcm x ox,dvsk.y,y..r dwm1 :5o(;( wsffae.

Is it possible to boil water at room temperature (20 yq :5yw8gyd s:le*mgj,mx q,le2x;5f$^{\circ} $ C) without heating it? Explain.

Consider two days when the air temperature is the same but tyf 1wl6gw9jrg1 w0w;phe humidity is different. Which is more dense, the dry air 0w6yw pw;f1r1w g9jglor the humid air at the same T? Explain.

Explain why it is dangerous to open the radiator cm9z*s* 6x/sy q:pcswq ap of an overheated automobile enycz9 *msswxq: pq/6*sgine.

Why does exhaled air appear as a little white cloud in th7x*n nm m)oap1p+;dljfk 7 6gfe winter (Fig. 13–28)?

  How many atoms are there in a 53vwb)cs:,aswi k-yy6s q5hd3.4-gram copper penny?   $ \times10^{22}$ atoms of Cu

  How does the number of atoms in a 26.5-gdmrl(* ,csw (a-3iylcram gold ring compare to the number in a silver ring of the samel,idwr-cayl((* m 3s c mass?$N_{Au}$ =    $N_{Ag}$

  “Room temperature” is often taken to be 68°F. What is this on the Cels cvpq: j.,(zor 3mu-wrn c))tvius scale?nj3 c- )rzcu:. tqv(m) vpw,ro   $^{\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 lo6oj3cjtq,r*a ) q9 gcdwest temperatures recorded 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 thermometer, the alcohol column b0tqh+(h+v wazouw32 has length 11.82 cm at 0.0 wabh02qzo w + u+(vt3h$^{\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 is built of slabs 12 m lonhyn47cr,oq o txeonz, 5u 51r4g (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 (Fig. 13–29) is built of wrought iron ab yf6-dl8)e8hky8x l wpproximately 300 m tall. Estimate how much its height changes between July (average temperature of 25°C) and January (avyl lb868yf)w dekh8- xerage 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 larger than the rivet holoz:c +o k0bvn9e are often used and the rivet is cooled (usually in dry ice) before it is placed in the hole.o+: o bv9nk0cz A steel rivet 1.871 cm in diameter is to be placed in a hole 1.869 cm 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 water at 4 a)oir3 rcqx9+ fg48o()kbauqp jgf ; 7$^{\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 mvb.d7kvlj )6 fk89 rpin diameter. What will be its change in volume if it is h6mp9j df8v7b. lvr)kkeated from 30 $^{\circ} $ C to 200 $^{\circ} $ C?    $ \times10^{ -2}cm^3$

  An ordinary glass is filled to the bri,-sd9c/oxn4l( fjvl y m 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 of wat) qh.pn (;xdtoer 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,hdavj+8k uqq *r88al 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, n70 hrvn p37:sejgnzspe)t .d4arrow vessel so it can expand in essentially one direction only, show that the ef3eg7 dpnn74:phv0zs .ert)sjfective coefficient of linear expansion is approximately equal to the coefficient of volume expansion $\beta$.

(a) Show that the change in the d4l/x 73mhz4n x6xfre fensity $\rho$ 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 z rvpk7k(ll2h1 i ip0r9y q1* e3ia0xplength l and width w has coefficient of linear expansipxhyrqp2iv 7*lk ri lz1039 1ip(0ekaon $\alpha$ 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,*oua hi ,ham5d/0alta*;f 449mgtnj u $\beta$ = 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 of brass and keeps perfect tims(j zi (t ij5323oieoue at 17s jiizi ot35(o( 2uje3 $^{\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 thermomes-g g:zq( xc*nter has an inside diameter of 0.140 mm. The buc:qn-*( gxszglb has a volume of 0.255 $cm^3$ 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 ofqc5g3l 5h-da62xh rwn radius 0.41 m is rotating about its axle on frictionless bearinxaqwc 525l nghdr-6h3gs with 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 length when at 15°C. How much stress isg+p c 8(ib,tp)kzwla:xayabu f9y 4 kla3(,(d required to keep it atk (u,ap b4la(fywx )ap +i3yclk ,g(a89dbtz: this length if the temperature increases to 35 $^{\circ} $ C?    $ \times10^{7 }$ N/$m^2$

(a) A horizontal steel I-beam of cross-sectional area j, a /ys0,y,;d ejkwe9qne5m o0.041$m^2$ 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 134.12 :p*d yt3tq tyi;//bb:en nvn,2 cm at 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 the Kelvin scale: (8 x7exg4 qp;fftsr;v
(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 temperature on the Fahren0srt/vx02vw theit scale?    $^{\circ} $ F

  Typical temperatures in the interior of the E6or+n,xivy.sa4v q *parth and Sun are about 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 engine, air at atmospheric pre2c2i 0cm md x+xny+5a8ew 0mqassure and a temperature of aboutx2xcdanc+qma0e 8 iywmm0 +25 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 os w*adz6gxy0rv3j 7ym:w-m e -xygen at STP using the ideal gas law.    kg/$m^3$

  A storage tank contains 21.6 kg ofi7nrfd kn /)p. nitrogen ($N_2$) 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 18.56 ggcmcjee4* )y 1q7rf kg of nitrogen ($N_2$)
(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 gasalo9 ,ehax,iwr:0r d: is 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 holding 105.0 kg of argon gas atcpw2yi6f7gu pym9,zz m30yj. 6ml fs4 385m g 6 9f74zwmcyfpu6s3yl0zi, 2.yjmp K?   $ \times10^{ 8}$Pa

  A tank contains 26.0 kgvon5v8ae1h jex a765 w of $O_2$ 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 achieve3bhlh,+* lu7b2+ovs0qwvs0l uys9tsmeg z*;s its buoyant lift by heating the air inside the balloon, olhtvv 9s; 0 eh 3, qysbu w07zgms+l2l*+usb*which makes it less 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 air1jxfyh3 h f*7r 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+.q/cx+ e/ i*, u/q mzlchdtpk 18.0 $^{\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 escapen vl(-v .4kxugs a child’s hand at sea 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 molecules5xsbc4f:u*a vog9a/ 6wfh84an m2cw r / $m^3$ in an ideal gas at STP.    $ \times10^{25 }$ molecules /$m^3$

  How many moles of water are there in 1.000 L? How many moleculdh3vkwgls;sa6z - o9 d2fm* k,es?    mol    $ \times10^{25 }$ molecules

  Estimate the number of (a) mo g z0fj+ctp xswv;9)d/les,    $ \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 volume 55za fp;h:j8ja.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 ar)t nn24oi8co ke in each 2.0-L breath you inhale that were also in the last breath Galileo took. [Hint: Assume the atmosphere is about 10 km hi2o8i4 )nkocnt gh and of constant density.]   $\frac{molecules}{breath}$

  (a) What is the average translational kinetic energy of an oxygen mour, 0 1nse6l7hl tite ron3+f7lecule at STP?t e 1rs3hreui0lnn6o+7fl,7t    $ \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 the Sun at a tempmix869jsdkk)szp;x6 9 krv0(mii356e qwu nh eraturi9in;jdsk83qp6 k rz v(ex9mw )u6i6hs 5 0xmke of about 6000 K.    m/s

  By what factor will th(43zs-j jttkw+i 2xcme rms speed of gas molecules increase if the temperature is x w2tt -ikj s+c(j3mz4increased 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 fo,8:sv (n-m su;c4 epciusgh-k)v4 xycllowing speeds, given in units of km/s: 6, 2, 4, 6, 0v8 k()ce4,pmn4 g suc;u h:s-vc-yis x, 4, 1, 8, 5, 3, 7, and 8. Calculate the rms speed. $v_{rms}$ =    km/s

  The rms speed of molecules in a gas at 20.0(w(m/ s ; ;a 0q vmcz7eh0a:ds+wenhgu $^{\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 volufin-d;n ld2i+ me is held constant, by what factordf+ 2d-i;il nn does $v_{rms}$ change?   

Show that the rms speed of molecules in a gas isyh84 bic 6ltyh5az (xk 63lb,.u4jmie 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 the6,8gkcb6k-bfr+wtl:w mk go ) same temperature, the ratio of their rms speeds is equal to the inverse ratio of the w6 w+)6kobgrmgkblk :8 f ,-ctsquare roots of their molecular masses.

  What is the rms speed of nitrogen molecules contak(mqsv7 ;lqg3 qz.e,hined 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 rmvv yk2 mqh7(ne4hkq *n ac+:h6s speed of an oxygen 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 distancyihw+0 ru/ f6ll0ps+ av45 r gavzg,c -2rsal+e between nitrogen molecules at STP?    $ \times10^{-9 }$m

  (a) Estimate the rms speed of an amino acid whose fnhkl/ f)kt8idls(d2( 6ttmd8r b g1- molecular mass is 89 u in a living cell atmi/1(hbfd dn t86ktl2 ()fsr8d-gkt l 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 -b.mi ax1sl9jP of a gas can be written 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 uranium,yu6 mgflb/ f0 xxc*0o3 $^{235}$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 pressu.93a.tfgtsh v qzf01o re, 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 pressure is 0.8lh j: ,7kmse4t m6ian01 atm and the temperature is (a) stn:8,jami7h6 ml4ke90 $^{\circ} $ C, (b) -20 $^{\circ} $ C.

  What is the dew point (approxiizw.1wh s77kfmately) if the humidity is 50% on a day when the temperaturefwki 7z. hs7w1 is 25 $^{\circ} $ C?$\approx$    $^{\circ} $ C(Round to the nearest integer)

  What is the air pressure nkdjgu oam a, 8al5*61at a place where water boils at 90 $^{\circ} $ C?    torr    Pa    atm

  If the air pressure at a particud-gyu,y/cyu 2z vs 81hlar place in the mountains is 0.72 atm, estimate the2g ,z-yd8hy/sucv 1uy temperature at which water boils. $\approx$ =    $^{\circ} $ C

  What is the temperature on a 1i (lf ix9t(hdday when the partial pressure of water is 530 Pa and the relative humidity is 40%?(dfx19t(li hi $\approx$ =    $^{\circ} $ C(Round to the nearest integer)

  What is the partial pr h3sv9ci n1k 5im*8wctessure of water on a day when the temperature is 25 $^{\circ} $ C and the relative humidity is 35%?    Pa

  What is the approximate pressure inside a presg+iu/8nfi fk, sure cooker if the water is boiling a,kff/ingu+8i t a temperature 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 of volume 68esh*pk;nyy )n+vf): m0$m^3$ at 25 $^{\circ} $ C is 80%, what mass of water can still evaporate from an open pan?    kg

  Air that is at its dew point of+ /d:7jiubc j)a. i obc48dwdb 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 for a glycine sqep:ypuk.75 4m0eaei,sq) xdr+6 xn qmz2. tmolecule (see Table 13–4) to diffuse a distance of ieex.2q .)yqsp07umaxpz:e n+t6,r4 d sq5mk15 $\mu m$ 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 insects to u;*xhx msx o/u7*zex1u) 9xtv the interior through tiny tubes called tracheae. An average trachea is about 2 mm long and has cross-sectioxo ;*uxe s*9m xv)7xz1x ut/hunal area 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 been calibrated at 20c aqu097y/tg l$^{\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 measu+n:cfr2n z ck+/x+6he im8zyhre 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 norma b i4vllqu1as)x92a (jl room temperature. How much error will be made in a recipe callingjlb2 aq91a()sux4 ivl 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 helium gas cylinder is initamw*xqs-i ) t3ially 28 atm. After many balloons have been blown up, the gauge pressure has dec3*i m-awt qsx)reased to 5 atm. What fraction of the original gas remains in the cylinder?   

  Estimate the number of air molecules in a room of length 6.5-3leg*w ,; :j6yrsj f wxjefe0( qv1jw m, width 3.1 m, and height 2.5 m. Afjfl1vse e jy(q0 j, j w3:6;-*wewgrxssume the temperature is 22$^{\circ} $C. How many moles does that correspond to?    $\times10^{27 }$ molecules    moles

  In outer space the density7ffqng . a fh9c*6ggb/ of matter is 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 usinm14 z6f jk;dcjg the best available vacuum techniques is about jcmf6kjd1;z4 $10^{-12} N/m^2$ 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 5.5 L when 10 m bel csiz27rirh)cb 9v*l *ow the surface, to what volume would his lungs expand if he quickly ros*r lis v*zic)7chr 29be to the surface? Is this advisable?    L

  A space vehicle returning from the Moon enxzjk* vfq )(x8l; h0)pehw5jw,oed.n ters Earth’s atmosphere at a speed of about 40,000 km/h Molecules (assume nitrogen) striking the nose of the vehicle with this speed correspond to what temperature? (hpe.) x,w jokw 8v* 0lqn de)x;5(hfjzBecause 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 increp e2.ikfx kw/zt) 3ne1ased 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 btkpa-*z* uh*of 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 of atmospheric pressure at the surface of the Ea8qzlg e az)o;:rth, estimate the total number of air molecules in the Earth’s z:eqa8z;go) latmosphere.    $ \times10^{44 }$ molecules

  What is the rms speedu hny;vu .v8jk c1n4(f of nitrogen molecules contained in a 7.6$-m^3$ volume at 4.2 atm if the total amount of nitrogen is 1800 mol?    m/s

  A standard cylinder of 6l+nd/vm6-j z +eo4ms3 zryugoxygen used in a hospital has gauge pressure = 2000 psi (13,800 kPaels 6gn/+ jzy-muz4o36mv+dr) 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. $\approx$    hour

  An iron cube floats in a eym1wdbxuhk yd.*/70 bowl of liquid mercury 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 gasolinjp8tswda, z; bz9em cghg:dhtkt *lf11+ 4m 37e at 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 thes b)at +9v;q nrr-(zdg Earth’s equator 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 tightle 4nh3gll, ,tnbrso7+ y onto a 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, adopted in thp79 7tnfogh6 0o mw:wme 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 charged, has a pressuzpzm7n 4o /recou1 bfyu9 3(1pre 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 th6ivjgik)2( q+ o: +xg,mwd e1vxw* cswe Earth is $ 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 suspem hu) kax.(s6nsb2q2 +w/ jwjvh8 gz/cnded against gravity by tennis balls thrown vertically/gshb62 j+hvsjc2ak. n /u8xmw)z( wq upward at it. How many tennis balls per second 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 3.00-cm-diameter (spherical) bubble of air from aolmp*i5 lxdy,)d q- 5a depth of 14.0 m in a lake. Assume the temperature is constant at 298 K, and the air behaves as a p*q)x,ldpioyd5a m -5l erfect gas. How large is the bubble when it reaches the surface?    cm

  Calculate the total water vapor preh ck2-3b)aont 9,ke tassure in the air on the following two days: 3ka n-,th ae)k2cb9ot
(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 differetf/rbprp2k -y (- 1leince in the density of iron at STP, and when it is a solid deep in the Earth where t y p/elbr1krt 2pi(--fhe 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 law to show that, for an ideal gas a)(xydz( .q fi7:,uaw c1zkonw6j+vs st constant pressure, the coeffic kczfo ud:q+zv1s a(sw. i(y,j7n6xw)ient of volume expansion is equal 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 cellar vh9:ft1qfuo4j w 3h2ns to prevent rot and mildew. If the cellar in aqnto 92w:hu j3h1 ff4v 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