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Unformatted text preview: Chem 105 Nielson Recitation 10/18/07 Boyle’s, Charles, Avogadro’s laws
Ideal gas law Stoichiometry, MW, density calculations Gas laws
1. A 512 ml sample of gas, in a cylinder with a movable piston, at 0.000 °C is heated at
a constant pressure of 0.800 atm to 41.0 °C. What is its ﬁnal volume? Ans. 589 ml V; v 1 Vi. : 512M<§ﬂ>2 ESQML
,f‘ / {— 7‘5 Z73r/‘5K ————— lL bf Mate: mime
. _  \ . 2,. , in) in Tr»
LNW'ﬁe/Q ~4=€NQ I. 1275.15K T. = BILL/5K Kjb‘fi 2. A 1.20 L sample of gas at 27.0 °C and 1.00 atm pressure is heated to 177 °C and 1.50 atm ﬁnal pressure. What is its ﬁnal volume? Ans.>1.2’0 L x I ’ 91/137186 v hL'
RV. _ “PM V1 1 \/L' 21 (.1 . WLLW 450.1%
—:=— ' ~——— ~ T. mm 5... (c
I L Tr P‘C ‘ I >
. y z 2 20 L P
T; = 500.1514 TL. =4lbOJ‘3K ‘( MMW ,
3. A 0.50 mol sample of air is conﬁned anOD’ C in a cylinder with a movable piston. The (Bl/390916 air has an initial pressure of 760.torr. The gas is then compressed by the piston so a‘( that its ﬁnal volume is half the initial volume. The ﬁnal pressure is 1.672 x 103 torr. 0W.
What temperature is the air now? Ans. 27 °C WDLVL V 2V; ._ H ._. Tr : TL BXW), 273.51 witﬁgﬂﬁlw if)
a .7" ’ ‘ﬁvr Z L
L T; (1);, Vt" 7W
.4” T35005K= Zléi/x ‘
V “ ZV‘ ?  r . .
Ideal gas edcuation L Z1 '€ 5 9606‘? )W K 4. Calcium carbonate decomposes upon heating to give the solid C210 and the gas C02.
A sample of CaC03 decomposes and the C02 is collected in a 250 m1 ﬂask. The
pressure of the gas is 1.3 atm and the temperature is maintained at 31 °C. How many
moles of C02 are produced? Ans. 0.013 mol C02 0303360 “:7 6906;) “L C0260)
“Pvmm 7" 5‘ +275 0 2 = amen/14002,
RT (0.0821L'm (504 k2 lame 5. What volume in liters does a 1.50 mol sample of H2 occupy at 55.0 °C and 1.00 atm
‘7 _. 
pressure. Ans. 40.4 L T: Z 7 5‘ (6 + 5510 3 57/9. (.3 K @chRT‘ _ i _ V? MT : (150M) (0.082062%: (328‘ “3'9
' P {,dbalh— \/= 40.4 L Variations with mass, Mm, and density
6. A 20.00 L vessel contains 0.200 g of 02 at a pressure of 0.0100 atm. What is the temperature of the gas? Ans. 390.K ?vvaT .,
71? (0.00 (025nm s (aoszotom) —»———— m: 0.200 02,. W = 0900225 NW 502
32.0:33
e 7. What weight of C02 is requir d to fll? a 10.0 ml ﬂask to a pressure of 1.00 torr at
30 °C? What is the density of the C02? Ans. 2.33 x 10'5 g, 2.33 x 10'3 g/L 790/7 VHQT 17: I‘ww [Elm 11.3Hasélo‘gaflh‘ “Watt? _ 760m “,7
pwbalolA/(SK m ; LE! _; (Lamp x 10‘7’glw.)(o.OloL> 35'28‘3) )HO WCQS
awe/“WW 0.055206% ,1} r “I; .
4mm”.li RT ( 7 W‘KXZZ 3,“) _2.33 no . C02
(1:03.111 m;%: (5.283) x .0“ s I « 5
WW6 col dag] 32.53X10 3 t .07) ‘l‘ow/ 8. One of the methods of estimating the temperature of the center of the sun is based 0 (0 low L)
(\S OWWA the ideal gas law. If the center is assumed to consist of gases whose average —_ Z. 33 X ,0—3
\ molecular weight is 2.0 g/mol, the density is 1.4 g/cm3, and the pressure is 1.3 x 109 atm, what is the temperature? Ans. 2.3 x 107 K 1.5»:ch
H hm twat/A : Wm, ,, ([35 mo‘1 AMMzo'almer?)
wM1. L MW 1 = 2.3 “’10le 9. A large ﬂask is evacuated and found to weigh 134.567 g. It is ﬁlled to a pressure of
735 torr at 31.0 °C with a gas of unknown molar mass and then found to weigh
137.456 g. The ﬂask is evacuated a second time and filled to the top with water. Its
mass upon reweighing is 1067.9 g. What is the molar mass of the unknown gas? The
density of water at 31.0 °C is 0.997 g/ml. Ans. 79.7 g/mol, Hint: First calculate the
volume of the ﬂask from the volume of water that ﬁlled it. Then solve for molecular . mass. 137.451.; ﬂ : pv (o am;ch ﬂaw.) a 0 03% W
m C m ~5 416 7 #6435 : l
N 0.0302/ml (Ky; lgz‘gzq QT (0.082002%(504J5K) “1077333511 WBSW ‘3'”? .03ch v= MB“ > W439"
r W V 7 wow (imam 0.0197 WM “‘L ...
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 Spring '07
 Macedone
 Chemistry, °C, final volume

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