Which has more atoms: 1 kg of iron or 1 kg of aluminum? See the periodic u8 ka9st5jts4table orts t49a k8u5js Appendix B.

Name several properties of materials that could be exploited to make a tz9ln1wb *hglz llg;/5hermometen9bgwlhl;zl*z1 g/l 5r.

Which is larger, 1 C 80mf :,acu;wl+nm y fe$^{\circ} $ or 1 F $^{\circ} $?

If system A is in thermal equhl/ /hd5+ bi *:kb) rd4 u48( zegftfgsnl/ekuilibrium with system B, but B is not in thermal equilibrium with system C, what can you say about the tkrits()5lek 4g4lufb/ / :gh8/h+ezb*du nfdemperatures of A, B, and C?

A flat bimetallic strip consists of aluminum riveted to 5h, :yivup9le y:8ckza strip of iron. When heated, the strip will bend. Which metal will be on the outside of the curve? [Hint: See Table 13uyy8,zh:9:cie5p lv k –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 linear expansiodzj 0wt)2af :qjiiio h7;63r in $\alpha$ 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 simphi 9xvxg4l)q 6+ h; is2/nfqerle thermostat used to control 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 touch both contact wires. Explain how this device controls the furnace and how it can be set at different temp/+q4qfvxh 9sh i6;r )2gelinxeratures.

Long steam pipes that are fixed at the ends often have a sect+o:z (c3o+fqp5q*jer1tvce x x)dtm4 ion in the shape of a U. Whxvq e: +oz3)roxce p1f(tq4dt+5*c jmy?

A flat, uniform cylig,3yag mymis26sp f6s wga( 7r6;4 jrynder of lead floats in 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 o1whixom(18j placed in a hot tub of water, th ohj i(18w1mxoe mercury initially descends a bit and then rises. Explain.

A glass container may breakeq th9la ni 2(4g,tm z9sc/0ya if one part of it is heated or cooled more rapidly than aqa,te9 9(04/ yzghiamtcl s2n djacent parts. Explain.

The principal virtue of Pyrex glass is that its coefficient of linear eaj:5 0k lpw od7)wiq6vxpansion is much smaller than that for ordinary glass (p5jwlo7q0a kw)i vd: 6Table 13–1). Explain why this gives rise to the increased heat resistance of Pyrex.

Will a grandfather clock, accurate m/ ymtrr:y.s9at 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 b he21k, mcjga;. fc6zyfe)zr8ulge so badly the can will not stand up. What has ef6c8gm zaz e.cy,hrj) k;f21happened?

When a gas is rapidly compressed (say, by pushing dow*n) f*6spho s zcx/k5on a piston), its temperature increases. When a gckxn)/f oo*hs *5sp6z as 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 increpeqa95ijcv p+,2da14 zdnv-eiy o/4c ase or decrease if the temperature is increased4idp ,ej5czqa/oa9pn2dc 14i+-vy ev from 20 $^{\circ} $ C to 40 $^{\circ} $ C?

Explain in words how Charleswgydfpz6b , (0+p ro o74vdrs1’s law follows from kinetic theory and the relation between average dp6+s,vd orb0wyfr g(471pz okinetic energy and the absolute temperature.

Explain in words how Gay-Lussac’s law followsv h1uq4mzkja( f6c 8;)5tntai from kinetic theory.

As you go higher in the Earth’s atmosphere, tc1 epzvhznnonli*f/ c( 25 -7 hjknw10he ratio of $N_2$ molecules to $O_2$ molecules increases. Why?

Escape velocity for th9c (8 wrwhjd3pe Earth refers to the minimum speed an object must have to leave the Earth and never retuw 9hr3 p(wjcd8rn. 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 quickp1zsa* he0 i-nly than water at room temperature. What can you infer about s h*-ze 0nia1pthe molecular properties of one relative to the other?

Explain why a hot humid day is far more uncog5h1eigfah u) d) h m5)9qsv74y,ac nkmfortable than a hot dry day at the same temperat 4)e,)n dh)g71af5ghmuhv scy9iqk a 5ure.

Is it possible to boil water at room temperature (20 t+4/wgjwzz.g$^{\circ} $ C) without heating it? Explain.

Consider two days when the air temperature twx 2wjb7: )+j3az hxqis the same but the humidity is different. Which is more dense, the dry air or the humid ai:aj 2jxwwq3t7 z )bxh+r at the same T? Explain.

Explain why it is dangerous to open the raa.,o 87p ic2j n2kur. -go 6mf(fqkrgxdiator cap of an overheated automobile engin2j(q-.8gur 2ki m gff r,7c x6oankop.e.

Why does exhaled air appear as a little whi +4m,v r6bqofqu7onkkm84v/(u axfb 8 te cloud in the winter (Fig. 13–28)?

  How many atoms are there l5f rs3ln 5)d05u 2yjyaq9)l yg3dxwo in a 3.4-gram copper penny?   $ \times10^{22}$ atoms of Cu

  How does the number of atoms in a 26.5-gram gr0mus,um5pnv ; 5cz5s old ring compare to the number in a silver ring of ;,p c m zu0mn55urvss5the same mass?$N_{Au}$ =    $N_{Ag}$

  “Room temperature” is often taken to be 68°F. Wh+v8ev8qciglnlw3x v rji+0g z8. (b*ag(3zp cat is this on the Celsius scale?(v3+glzi *r.gxl n3ibcq8+e 88 wcjvgz0ap( v    $^{\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 temperat e c+cu3s35twrures 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 has length 11h 0/.nh8;artdtl+ jwxyx/t 9m .82 cm at 0.0w/8t;/9j+ mr 0dxh a txnh.lyt $^{\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 longmkf 4 ay.0 l,ez*3)idwt5sklh3ikqx3 (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 +7prfv3h8 f coiron approximately 300 m tall. Estimate how much its height changes betwee+3 o chvpf87frn 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 larger thabp/ 6h*puihx,mefl4. n the rivet hole are often used and the rivet i4x uf,m*h. /h6pipl ebs 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 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 a.,ht4+y 5 v/gdqcfn v jov 6otavk*p2)t 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 :1r6 /ky xljo ceu9tlxcq)5 s.h+m-jzbe its change in volume if it is hyq ecjjk hlo9s65:1r)m c .zx/+x-ltueated from 30 $^{\circ} $ C to 200 $^{\circ} $ C?    $ \times10^{ -2}cm^3$

  An ordinary glass is filled to the brim wiu53 o6rqhn*dy ap8az*th 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 wme j 4- *rn8xd:*+7s6fydtii;xanz fqater 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 mad3me-vjc1 k4z7o ol/s5dfm yg0 e 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, nauju4ga5;e 9yxf +nqanlh * e/x15dp.k rrow vessel so it can expand in essentially one direction only, show that the effective coefficient of linear expansion is approximaelueqfk/4a p .h;dnx*1ya +jgxn 595utely equal to the coefficient of volume expansion $\beta$.

(a) Show that the chanrws* mqw5 j8l.ge in the 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 coefficient offk, yhims;q2 7qogw8r 8kvz -0 linear expansik- o ry87vik;0 m,fs 8whq2qzgon $\alpha$ 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 s:y ,/irz ho 4(rxt;wilolid, $\beta$ = 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 timev1k, mhl5tv z t,rh.nc3y0hb/ at 17 h3ycnktr5vzlb1t /h,.vm, 0h $^{\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 diamejyoy l( 4ghs-g9ff :n;ter of 0.140 mm. The bulb has hg4 -y nygs j;fo(l:f9a 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 of rp4+ .rhb 2udtyta()n.l b5kleadius 0.41 m is rotating about its axle on frictionless btn + ylap5.. dt2kerbbl(h 4u)earings 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 lena 3;krxook/-:labzvun3c, a: gth when at 15°C. How much stress is required to keep it at this length if the temperat-,uc 33 rzao lxk:o; /aankvb:ure increases to 35 $^{\circ} $ C?    $ \times10^{7 }$ N/$m^2$

(a) A horizontal steel I-beam of cross-sectionafy 6 k;ry(qa*/hdt3qdl 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 *rg7 md6n7r ho87lvdfcm 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 j.)vsu.tr z1i-ixy w.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 temperature on th ;,z jz g.58iemn;qo m-xxi3vqe Fahrenheit scale?    $^{\circ} $ F

  Typical temperatures in the interior of the Earth and Sun are about 400hv. r55bh,quo,cc-lru3dc -v0$^{\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, ai1 ltrwpbg *4u-pd*gkd*ml f8/7w.jejr at atmospheric pressure and a temperature of4 **gek g/rljwf- 17jp pm8wubd.ld*t about 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 STP using the ideal gas law. 76nrt nvxb.dyj;;y bgkq( e5)   kg/$m^3$

  A storage tank contains 21.6 kg of lvsp r(h*t324 t e4ntbnitrogen ($N_2$) 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 1c zcee3 3c6oz58.5 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 gas:tx:osk/3 qseus1h)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 k1f1vnsdeg r c39vg (.of argon gas at 385 K?fc1s93g.reg n1kvd(v    $ \times10^{ 8}$Pa

  A tank contains 26.0 kg o 9f:mxr*ik7o vpe, j+mf $O_2$ 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 achieves its buoyant lift by heating the air inside theohd.q lhf;k,zccj6+ 4 balloon, h ;cdo4kf.+c,zjl 6qhwhich 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 air z bbw2 5q;q-vso;ik.aat 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 a:e8a)s bflz)it 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 escapes a child’s hand at sea level and 20.0 )z/a vi70hlf.d p6md 2hre, yi$^{\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 moleczr:7euhiqnr/. 3q6t k.k6rks*y l ad(ules / $m^3$ in an ideal gas at STP.    $ \times10^{25 }$ molecules /$m^3$

  How many moles of water are there in 3(avc 0ls*0rza65a yd2dytv t1.000 L? How many molecules?    mol    $ \times10^{25 }$ molecules

  Estimate the number of (a) g1u3 ju zxv*vyavd jc75oo4 hv.sa0d-ux0k (3moles,    $ \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 5hg 3(ypiba eo;z(*fy/.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 2.0-L breath you inhale )a fe8cduwe:t*,b/ zythat were also in the last breath Galileo took. [Hint: Assume the atmosphere is about 10 km high and ofceuf/:8, )azt e*wbyd constant density.]   $\frac{molecules}{breath}$

  (a) What is the average translational kinetic energy of an oxygen mol uvlu6/6rr18 q(zkakt qhq3p3ecule at STt1rrklauqhp3 z qv(6 qu/k86 3P?    $ \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 surfap 9 r,vlx/8y8fu5s tvyce of the Sun at a temperature y8uvs,vy p/r5 lfxt8 9of about 6000 K.    m/s

  By what factor will the rms speed of gau.j1(vyodg7k3p k nr4s molecules increase if the temperature is k v.uj71dkn ( ogry4p3increased 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 following speeds, given in uniq22*saqmmwy 0+jtkkhe 5a(g5ts of km/s: 6, 2, 4, 6, 0, 4, 1, 8, 5, yw2eh0k 2a5 5tm*gjq s(a kq+m3, 7, and 8. Calculate the rms speed. $v_{rms}$ =    km/s

  The rms speed of molecules in a gas at 20.0 ,he3ml /1vctk $^{\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 dolytl05oj * o,4v 3d/lu5 qlwooubled while its volume is held constant, by what factor doelo34/,d tl*l 5oqw5yvu0 ojols $v_{rms}$ change?   

Show that the rms speed of . i,:)o:dnd dwlsy dz5molecules 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 temperatoc2 k jty:y4 z(5xep88 hm6uhture, the ratio of their rms speeds is equal to the inverse ratio of the square roj8t4cph8y x ukt :(5zmeh6 y2oots of their molecular masses.

  What is the rms speed of8 5z i3 o(ph m32,clo+vzhmx(gz(eaxi nitrogen molecules 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 rmscg8e efrz 60y c8(+nix 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 distance between nitrogen molecules at STbvzyv: 3pjfc0ez0 l6 rt:c. fd://xhtP?    $ \times10^{-9 }$m

  (a) Estimate the rms speed of an amino acid whose molecular/f5r)ktc qdd oi6ixpm/ u5/ 0e mass is 89 u in a living celr5d p5x6/ q/fom ik)i/detu0 cl 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 Pd57oo *e+pdyena*;z q 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, 7rbdcp wty c8m6 fgc;01t3lx: $^{235}$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 pressure,l8hbkbk0 1-pmo e ;l8i 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 whq;)/5xjlppbh bjdat) s;d7d5* eqdil4* d y* den the pressure is 0.01 atm and the temperature is (a) 9db7lq*ad*dt/bp)h ye x*d;j ;q li5)pdd5 j4s 0 $^{\circ} $ C, (b) -20 $^{\circ} $ C.

  What is the dew point (approximately) if the humidity is 50% o ;ayj/dvq)hm k:1br*fn a day when the temper/1jrdqb k *hm:; yfva)ature is 25 $^{\circ} $ C?$\approx$    $^{\circ} $ C(Round to the nearest integer)

  What is the air pressure at a place where water boils at 90fpn2cvx84v5aelh *(tu9h c t9 $^{\circ} $ C?    torr    Pa    atm

  If the air pressure at a parti4-ixu /ba rh,-va vj+mcular place in the mountains is 0.72 atm, estimate the temperature at which water boil4a/avm, v- ru+i xbh-js. $\approx$ =    $^{\circ} $ C

  What is the temperature on a day when ,zr-5dlfj s 2nthe partial pressure of water is 530 Pa and s l2j,f-rd5 znthe relative humidity is 40%? $\approx$ =    $^{\circ} $ C(Round to the nearest integer)

  What is the partial pressure of water on a day when t u22ey2.ees gjhe temperature is 25 $^{\circ} $ C and the relative humidity is 35%?    Pa

  What is the approximate pressure inside a pressure cooker if thyq8p85poj r:lrcf hwpod 1 *66e water is boiling at a temperature of lwo8p pp5q6rc6yh dj8:ro f1* 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 vegt 6u;wc6f y; vra.89rorcu 6olume 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 point of 5 ,m x9i)a y; bjdy*p9xl$^{\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 molecule (see Table 13–4)oad4yc3eo.zq hod7:+ to diffuse a distanceze7hoqycd :+od. oa 34 of 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 s3l op : a,s-esadv3;qza/cfyls8)b9 f urface of insects to the interior through tiny tubes calldcb3/e: ya svll-,9afsp3 z;ao)fs8q ed tracheae. An average trachea is about 2 mm long and has cross-sectional 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 calit;3 ci oxktd1s, p51lpbrated 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 measure0t,x6jvf,dln c: aefi( bj+t *j8ct.l 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 calie5.c)k8dx a6uv9 d pocbrated at normal room temperature. How much error will be made in a recipe calling for 300 mL 9acxd u.c vpdo e5k8)6of 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 initially 28 atm. After many bal4hz)sz2xxa)( ie 1y enloons have been blowny1ha4 e2z( )xnesix)z up, the gauge pressure has decreased to 5 atm. What fraction of the original gas remains in the cylinder?   

  Estimate the number of air mo3pjqlx1uh vu -)8/ 5v3s h b6jzrxz+jmlecules in a room of length 6.5 m, width 3.1 m, and height 2.51)bzqm/hxpzj3 r5 8sjjvh6uvx -3ul + m. 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 about one atom per f qoe) ea,3 kgdm77yx.$cm^3$ 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 available vacuum techncrdl(ep5+h6zuh ba 9) yl9;xfiques is abo(phxy) d+h65 e9;ca z9lrlu fbut $10^{-12} N/m^2$ 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 whx0w47,4vtxqk v/zv nuy88knf en 10 m below the surface, to what volume would his lungs expand if he quickly rose to the surface? Ikv478q n/,xv4un vtwyf 8zk0xs this advisable?    L

  A space vehicle returning from the Moon enters Eartb( 9v5,xs-f,i:mtfj.hc q p qkh’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? (Because of this high teh x(:c5f mv9p,,i -bqsqtkjf.mperature, 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 8;lrhp lb,ltk3gui.az.* l l3gas is increased 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 o g2voqa61vugvp b)ogny*x;2s(2 vd ,qf 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 jkgfrlz4btx3qq:7/t uc 911iof the Earth, estimate the total number of air molecules in the Earth’s rxqjql 17fg ci/4t 9buzk1 :t3atmosphere.    $ \times10^{44 }$ molecules

  What is the rms speed of oh izyvw 2o :pp:m385gnitrogen 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 ofpv;o):- od u(y m*( qdgr)cjvwega:*y oxygen used in a hospital has gauge pressure = 2000 psi (13,800 kPa) and at T = 259K How lo:g * ;vuo)d-)rvwpcajem dyqo(*g(y: ng 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 bowl of liquid t(oewswry /77 pkqlg1 :+p(wjmercury 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 gasol ov0 )bu1ocov.ine 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 k c tkk. lc5g779n:pijfit snugly around the 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 tightly onto a glass jgxrl 4 4jh6 x3vvs61f. djh.kwar 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, adto1sgm krz 83sbo:syl-mg 4+/opted 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 charged, has a pressure of 195 atm at 2gawdfh /6y/ b)c8xc5 m0$^{\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 f*/inb o3xvf; the 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 suspended against gravitjd4(8w : v0okyrf. zzoy by tennis balls thrown vertically upward at it. How many tennis balls per second must rebound from the lid elastkd:8of4yz 0.vjoz(rw ically, 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 airr.mw,aey-sf2 tbnz ., from a depth of 14.0 m in a lake. Ass.y,2. ef tm s,n-bawrzume 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?    cm

  Calculate the total water vapor p/ w/05f7e+(t rhh i 1xqwmgwleressure in the air on the following two days: hr0hfxee 1il5/q+7wm / (wwtg
(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 depsqa9 zaik:0,nsity of iron at STP, and when it is a solid deep in the Earth where the t ka9pi,szq0 :aemperature 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