Which has more atoms: 1 kg of iron or qspl0/zau:5a*w z 4.7x z 5tns wwf)qz1 kg of aluminum? See the periodic table or Appen lus5f w/ awzz0*z: sq4q5z7. xwat)pndix B.

Name several properties of materials that could be exploited to make a thermt * m4dwwp1xzuuri6g m*cq4, 0ometetxmcw w4u4r*, uz16 mi0*pg dqr.

Which is larger, 1 C gcdjtm43ve 8+$^{\circ} $ or 1 F $^{\circ} $?

If system A is in thermal equilibrium with system B, but B is not in thermal eq;b n t1r 2myiev 82.h58inakawuilikaivt nhwy 2;r5 2ab8n.ei 8m1brium with system C, what can you say about the temperatures of A, B, and C?

A flat bimetallic strip consists of aluminum riveten 6 h*wzjwm61id to a strip of iron. When heated, the strip will bend. Which metal will be on thmw66i wn h*j1ze outside of the curve? [Hint: 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 lins :*pticjk/a,fpif4- n 7b1wi*yb1 le e6w:fvear 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 is6vs ua3(1jja simple 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 contvsisj3j6( au1act 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 sectid*ps q;g9i 67qgy/flr on in the shape of a U. sq 9 ypglr; i/dq7gf6*Why?

A flat, uniform cylinder of lead floats in mer6bgr1ay,yw qt)e9ki67w t ku ,cury at 0 $^{\circ} $ C. Will the lead float higher or lower when the temperature is raised? Explain.

When a cold mercury-in-glass thermometero .d6k qk9xr0m is first placed in a hot tub of water, the mercury initially desce9 kkq60rdomx .nds a bit and then rises. Explain.

A glass container may break if one part of it is heated or cooled m )1k k dqmmv6bc75d-rlore rapidly than adjacent pvk -)bcr7k 1ml6 5qdmdarts. Explain.

The principal virtue of Pyrex glass is that its coefficient of l ,mc*(:x vrmv(hoe+ ssinear expansion is much smaller than that for or e m*cvhvs:+s(o(mr ,xdinary glass (Table 13–1). Explain why this gives rise to the increased heat resistance of Pyrex.

Will a grandfather clock, accurate atza;w 3nwv,csv;, sn3t 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 s +c8kuotzgw ;1o badly the can will no+ oc8w t;gz1ukt stand up. What has happened?

When a gas is rapidly compressed (say, by pushing down a piston), its tempexdl4 1xokft v t*,uh6ld;z1 a-rature increases. When a gas expands against a piston, it cools. Explain these changes in temperature using the kinetic theory, ixt;dd , tx 1ll*kh1za o4uv-6fn particular noting what happens to the momentum of molecules when they strike the moving piston.

Will the buoyant force on an aluminum sphere submerged)o-elsf a /3umgi el5; in water increase or decrease if the temperature is increasf3ai )e/ su- l5lg;emoed from 20 $^{\circ} $ C to 40 $^{\circ} $ C?

Explain in words how Charles’s law follows from ki6 mfqj2rfa*q 0 / ei;awant,t8dcr c(/netic theory and the relation between average kinetic energy 2rt; /fdfctm8 w ja *an/q q0rce(a,i6and the absolute temperature.

Explain in words how Gay-Lussac’s law follows from kinetrmlk4k hwfvw bj.3ei23qv909ps2p8v ic theory.

As you go higher in the Epq 6u(bs( 2ywcarth’s atmosphere, the ratio of $N_2$ molecules to $O_2$ molecules increases. Why?

Escape velocity for the Earth refers to the minimum speed anuf6 pyl6 vdxcp8z*, +h63msf(z8 odr b 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 due to the Moon’s smaller mass. Explain why the Moon has practically no ypoc6u p6d+ r8dv(, zh36l zff*s8mbxatmosphere.

Alcohol evaporates more quickly than water at room tempuju+r z1+6m t8,hwr wherature. What can you infer about the molecular properties of o+ uzjw1mtu 6 rr8hh,+wne relative to the other?

Explain why a hot humid day is far more uncomfortable t(xkny*j l-+j,lcg(jjc 46hknhan a hot dry day at the samec(ngxclj* (-,jjykj+kln4 h 6 temperature.

Is it possible to boil water j opl2p a1w qrxy0xmye1 ;-0bnx-;0 jxat room temperature (20 $^{\circ} $ C) without heating it? Explain.

Consider two days when the air temperature is the s45omy2 dx k o5cu0l/yqame but the humidity is different. Which is more dense, the dry air or the humid air at the same T? l q/mu ykyo5xd240co5 Explain.

Explain why it is dangerou t:dmv v44dg .y4k)rwfs to open the radiator cap of an overheated automobile engined v:4)fvrd.y t4gk4 mw.

Why does exhaled air app;ky8+fw39 :cq tbx7x .fta n 9)tyfaatear as a little white cloud in the winter (Fig. 13–28)?

  How many atoms are there in a 3.4-gram coppe o- u+kwgf:tt-r penny?   $ \times10^{22}$ atoms of Cu

  How does the number of atoms in a 26.5-gram gold r-dmx lc ig v,; jszln8f9;k-*iing compare to the number in a silver ring of the same msjk- i8l gdx;9ml,*z ic;-fvnass?$N_{Au}$ =    $N_{Ag}$

  “Room temperature” is often taken to be 68°F. What hn4vxu+)vp21 zs-y8x, btvel is this on the Celsius scale?zul xnbvy+ 8 v4vse tpx,1h2)-   $^{\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 loxt8 n.jqi vqv0q61x.mwest 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 tty7qs8uvkzr o/t :ya7 7c.a,thermometer, the alcohol column has length 11.82 cm at 0.y 7q8oacatt ty7z /sv,k. :ur70 $^{\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 bui tz200uih;r1w z:kxdclt 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 (Fig.gb va7+h,9pa m 13–29) is built of wrought iron approximately 300 m tall. Estimate how much its height changes between July (average temperatv9pgm hab 7,a+ure 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 than the rivet hole are oa / szfuq;qj5 juo olic990 :3e2o8in6nc lhm2ften used and the rivet is cooled (usually i:u;q9ch ef2sc63z m9o8j2n i qul0jno/alio5n 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 at 456pn mwappq2 yyi06x3e. zoe v:scn3-t67spz $^{\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 wi vy9+a kniid57yho2m 9f4f0z xll be its change in volume if it is heatay9xn if ym2 o7kh9d4 z+0i5vfed from 30 $^{\circ} $ C to 200 $^{\circ} $ C?    $ \times10^{ -2}cm^3$

  An ordinary glass is filled to the brim with 350.06w/jc. 9 ivaznaw3(djjiaf tkd :;6-xvk :g) h 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 mLv*21ik0s-gd9a-iz mx b)p4 ej,zokw h of 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 made of ironlq ci0 -, 6f-wxb rwm5q*pt/ss. 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 in essen ;mv)lnaet.r t aso*9*tially one direction only, show that the effective coefficient of linear expansion is approximately equal to the coef;astlr)*ea .nt*mv 9oficient of volume expansion $\beta$.

(a) Show that the chanpvv a9 /nmx(g+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 widtezo .jh:6 8ejur hed*7((xmlv(5 t sw:vrub* xh w has coefficient of linear expansion zblr:xo 7.d: ehj rwv8x6 j * t(euu(hm5*s(ev$\alpha$ 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, 5gtc8:l am;d t1jb5cz $\beta$ = 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 io cc52uc7ko8y. +i qg+ob5 ddbrass and keeps perfect time at 17 ydic5uc d +kio2 c.75+g 8booq$^{\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 bu l h/q2)tm6l*o38-lzg3i khy ft9gvbwlb has a volume of 0.255 it lt -63 b fqk8l *vzh/2lg3hmgyw)9o$cm^3$ 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 0.0 5( gk5 b8aevgm-t:en7: tmaolrg u9w41 m is rotating about its axle on frictionless bearings with angularma e- etm57tukg08go b:5la( ng :9vrw 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 f2xel4 sctrs g6:u-0m:b,jximuch stress is required to keep it asbixl0mes,-6: juf4g c t r:2xt this length if the temperature increases to 35 $^{\circ} $ C?    $ \times10^{7 }$ N/$m^2$

(a) A horizontal steel I-beam )et.(aci, qt mof 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 z03nd ui3qh v;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 uoq i zxnt/554mb..jmKelvin 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 the Fahrenheit scale?7z/ bz2d caa*(i/ wrud    $^{\circ} $ F

  Typical temperatures in the interior ofa40 wfh, tci gj/1qis:-iyju9fpf940xpr0q r the Earth 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 atmo2qoa tis g3kq 2i:h,g9spheric pressure and a temperature o 9i qhaiktq2,gg3o2:sf 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 ojwi17 :hat)y;.qh2ua hqbk h- ofzv/3xygen at STP using the ideal gas law.    kg/$m^3$

  A storage tank contains 21.6 kg okyi )ran0ve k; 8k(j3lf 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 zb px4+hsf 6y,18.5 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 is a*t-da2bzn 5q mm5q)sl t 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 at3 e*--62kjk7 x o9zvj znpzalt.z4t brgon gas at 385 K?zjpzvj7-k 4.-et6 9nz 3tzxo2 b*takl   $ \times10^{ 8}$Pa

  A tank contains 26.0 kn)0 puf.v:ip j3mx7b wg 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 achieves its buoyant lift bs. x8ocr zu1sbo2fnl p-88z/r y heating the air inside the balloon, which makenzz px/r.o-ofbs 1crl2 us888s 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 ai:ghx*u jl vcavf );b-2fig*y:r 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 ddpmg6p ;k+luwfhk8x b- )(4u18.0 $^{\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 balloonfh,e *ljjbx2( 8 bxsc) escapes 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 molecules / p,dcb w+9q6v+cad: v0ua2ws- b 0ezhy$m^3$ in an ideal gas at STP.    $ \times10^{25 }$ molecules /$m^3$

  How many moles of water acj3xqb4qg9e6 cs3bz7 re there in 1.000 L? How many molecules?    mol    $ \times10^{25 }$ molecules

  Estimate the number of (a) mi3dpu. qxed6;pod581uz w, gcoles,    $ \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 5.1i;j.qmr, g/b p$ \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 eaczsb .fq5( oi9 8tr6xyu.gm j3mh 2.0-L breath you inhale that were also in the last breath Galileo took. [Hint: Assume the atmosphere is about 10 km high and of cq f(386.5y 9 imur .gstbzmjoxonstant density.]   $\frac{molecules}{breath}$

  (a) What is the average tra i)pom:k4t 99.i vnjq/l (pdranslational kinetic energy of an oxygen molecule at STPi.in/ )9 :ml4q9 ka(ojv rpdtp?    $ \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 Suntz*/opcgt//cg uw,v*19 r zgd at a temperature of aborv1cgg/ptug* z9 wc,ztd/* / out 6000 K.    m/s

  By what factor will the rms speed of gas molec sf -afcssmk4x.0t7x(ules increase if the temperature is increase-s0taf7 sm4 f.xskxc( d 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 havv+4aemr1( qcp/byw evj 9l(6vyx4pm6e the following speeds, given in units of km/s: 6, 2, 4, 6, 0,xre 6 b 1cq(pwmylj4 y v/vmv6pa+9e(4 4, 1, 8, 5, 3, 7, and 8. Calculate the rms speed. $v_{rms}$ =    km/s

  The rms speed of moleqpv1:c 8 :vyuycules in a gas at 20.0 $^{\circ} $ C is to be increased by 1.0%. To what temperature must it be raised?    $^{\circ} $ C

  If the pressure of a gas i+up:eyaw54ri /zw l4-eqh1; 3 zuhhut s doubled while its volume is held constant, by what factor z/e 4uwwzy a+31erp-hu5hl ; uithq4:does $v_{rms}$ change?   

Show that the rms speed of molecules in d7rhc o)apl.ko3; ,y::tq ymsa 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 s rbdhb1x*mh( p3 lrz4(ame temperature, the ratio of their rms speeds is equal to the inverse ratio of the square roots of their moled1(*hh p4x zb m(b3rrlcular masses.

  What is the rms speed ofzl 7wg:noo1n kq9(h 8a 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 rms speed of an oxygen mogj46x q)ywlp cp8oj 81lecule 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 di rvcrf/.cf 6o2,kd (utr,yz:v stance between nitrogen molecules at STP?    $ \times10^{-9 }$m

  (a) Estimate the rms speed of an amino acid whose molecular mass-t oa33 vl*b/biws .zew+m y:k is 89 u in a living cell at . o /bl:3w-vyek3tims+wba *z37 $^{\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 writ80l2v w* pu-oysils8uxo q1h 0qq 9l0gten 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 uranf8m5/2nw,-i u4+tyukryw kt hium, $^{235}$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, in w,e *w3a 9mmgiad0(blrj+fu rp 87 ;jgyhat 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 0.01 atm and the (hjopz)ifb 5b+5uf a4(v d q4itemperature is (a) b(4)dzha5v+ 5bo( pufj fq4 ii90 $^{\circ} $ C, (b) -20 $^{\circ} $ C.

  What is the dew point (approximately) if th tz:ixqe1h; a7e humidity is 50% on a day when the temperatz:;taxe q i7h1ure is 25 $^{\circ} $ C?$\approx$    $^{\circ} $ C(Round to the nearest integer)

  What is the air pressure at a place 1,;qo cl*:ia1s kh:f vrc9iyg where water boils at 90 $^{\circ} $ C?    torr    Pa    atm

  If the air pressure at a particular place in the mountains is 0.72 atm, fih9ipx32o j x38al,q estimate the temperature at w393ho 28 api,xfjlqx ihich water boils. $\approx$ =    $^{\circ} $ C

  What is the temperature on a day when the p bb9 6nvg pljrf1 v;d+(fr*/voeb:w1rartial pressure of water is 530 Pa and the relative hu je 9:(b*rf/d1rwlvb ;or1vbpgf +6nvmidity is 40%? $\approx$ =    $^{\circ} $ C(Round to the nearest integer)

  What is the partial pressure of water on a day when the temperature is 25 z11uj2 upfdxfs0,l r/ $^{\circ} $ C and the relative humidity is 35%?    Pa

  What is the approximates *(npih;u c8e pressure inside a pressure cooker if the water is boiling at a temperaturepnc;8hi(e *u s 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(vbhyj9t(2qjm .qn 0 6mxbxn7 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 de+ *)7wadilhodw point 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 for a glycine molecule (see Table 13–4) to dif74 fruz( vcrs ;fq)z4afuse a distance or)svafzuz7q 4 4;r( fcf 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 insects to the cd)*exn p8ba0interior through tiny tubes called tracheae. An average trachea is about 2 mm long and has cross-section)ex8ap *bn 0cdal 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 calibz8yjc h gam) h*:*6ddurated 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 measure has b3sv1cml2q rqlm (34g ieen 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 cabbl4n4d6 *a )dl r6wxulibrated at normal room temperature. How much error will be made in a recipll*uabd4x6 br) 6wnd 4e 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 helium g0inrbi g19 7c/vae u 7.f3+lz8gr nuidas cylinder is initially 28 atm. After many balloons have been blown up, the gauge pressure has decreased to 5 atm. What fraction of the original gas remains in v+91nf 3i8ul e. 7dunrz/7ggc aiib0rthe cylinder?   

  Estimate the number of air molb 6k39mdtcb uw ac5-s9i6 0sfnecules in a room of length 6.5 m, width 3.1 m, and height 2.5 m. Assns6tkdc99cu -ib5bwf 6s0a m3ume 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 abouvyjw 32qw8he5t 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 available vacuum techv/bmgi k267r kniques is abo g/mki 6rvb7k2ut $10^{-12} N/m^2$ 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.dd,l++ k br m1x3jo0i kufq7x95 L when 10 m below the surface, to what volume would his lungs expand if he quickly rose to the surface? Is this a7xm1f d9k+ 3l0rkbj+ x,ouqid dvisable?    L

  A space vehicle returning frm2co(9jb er- j:n o2r+o6jvrbom the Moon enters Earth’s atmosphere at a speed of about 40,000 km/h Molecules (assume nitrogen) striking the nose of the vehicle with this speeorbb c-2ojmo2n rj+v6e: (9jr d 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 ideb4,8stp.knj cal gas 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 volume7 wmx*j se(0oek2x-9i:rwag r 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 r ii)l5som7vdmw7)1l atmospheric pressure at the surface of the Earth, estimate the total number of air molecules in the Earmwii mo lv1l5) )r7s7dth’s atmosphere.    $ \times10^{44 }$ molecules

  What is the rms speed of nitrogen moleculeo 7.w(+xb.d 6jxser4xztykd* s 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 oxygen used in a hospital has gauge pressure = 2000 psij odr omgm u5hgx,0))t,u1f /c (13,800 kPa) and at T =uto/xg5 g1,hjd,r0mf mo)u c) 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 bowjz5dwq uj4qx)c9;66up6u bq *cj3 u1)kwud pql 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 gasoline v:t, t0mz nov.ydrz6 j :,3mjuat 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 fi,9d 3slef / z-w b.2f -btck)iu*7)wy yinisczt 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 tigh3zxozzn7 a+;f2jlgo 8p4 p j9etly 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 standarfp,s5ojoc9 +1s;a q lxd, adopted 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 fw*n z/h5u .bul+aj jzbooe://-*jnt 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 d*hw3z u -m 7l2ypsl*wthe 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 gravity by tenniz 49eyr/ prku 0mx*h2zs balls thrown vertically upward at it. Ho9h40z/yzux kmprre2 *w 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 fromdhm b1b(21uvh a depth of 14.0 m in a lake. Assume the temperature is constant atdm v1b2b(1 uhh 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 pressure in th/oo-f9ta c*r/ito: c ce air on the following two days: -rt afc it9/cco/*:oo
(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 diffeq sga9p4-xxw85 dj2qprence in the density of iron at STP, and when it is a solid deep in the Ea dgp-xs82x jqq549w aprth 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 law to show that, for an ideal gas at c(g nwh;dimo-w xc*,v bm f7)n1onstant pressure, the coefficient of volumbxd-m (wn)wcvm1n7o ,*hi f;g e 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 celu)cv (rjsez +ds,p+ f5lars to prevent rot and mildew. If the cellar in a5 ,p(s udefj+vc+ z)rs 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