Chem Gas Worksheet 4. Block:___ Teacher:_______. Name:_________________________
100kPa = 750.1mmHg = 0.987 atm = 14.5 lb/in2. 24.8L/mol @ SATP (298.15K, 100kPa.)
G. Two-variable Gas Law Problems.
a. 67.2 cm 3 of gas measured at 87.2kPa, 350.K, would occupy what volume at SATP?
87.2 k Pa * 67.2 cm^3
100Kpa
16.7 * 298.15
----------------------= -----------------------------------------------------350 k
298.15 k
100
_
49.8
cm3
b. 1.989L at 720. mmHg, 285K; at what temperature would it produce 1085mmHg in a 750.mL
flask ?
(720 mm Hg * .989 L )/(285 K) = (1085 mm Hg)(.750)/ (x)
309225 = 1432x
216
K
c. What pressure would be produced in a 6.00 L container at 400.K if the gas produced 4.55 atm. at 650.K in 8.50L?
(4.55 atm)(8.50 L)/(650) = (6.00 L)(X)/(400. K) 1820= 390X
______ .467
atm
d. 0.757 mol of gas at 285K, 151kPa; how many moles would be needed to fill the same volume
to 241kPa at 348K?
(151 K Pa)/(0.757)(285 K) = (241 K Pa)/348 K * N
51995 = 52548n
_______ .989
mol
e. 0.1875 mol of gas in 1050.cm3 at 1853mmHg; what pressure would be produced at that
temperature by 0.3336mol in 7.500L?
(1853 mm Hg) (1050 cm^3) / (.1875 mol) = (7500 cm^3 X)/(.3336 mol)
461.6
mmHg
H. Three Variables: The Ideal Gas Law.
a. What is the volume of 0.296 moles of gas at 302K, 139kPa?
139 K Pa –x = .296 mol * 302 K * 8.314 k Pa* L/mol *k
_
5.35
L
0.722
mol
b. How many moles of gas are in a 16.5L container at 345K, 125.5kPa?
125.5 K Pa * 16.5 L = 345 K * m * 8.314 k Pa *L/mol *k
c. At what temperature will 0.0958 moles of gas produce a pressure of 96.5 kPa in a 550.cm3 flask ?
96.5 k Pa * 0.550 L = 0.0958 mol * T *8.314 K Pa *L/mol*k
_66.6_____K
__________
d. What pressure will be produced by 16.5 g of helium at -125oC in a 10.6L container?
16.5 g He * (1)/(4.00 g He) = 4.13 mol He
10.6 L * P = 4.13 mol He *148.15 K * 8.314 k Pa * L/mol * K
480 kPa
e. What is the volume of 1.96g. of N2 gas at -39.5oC, 112psi?
112 psi * (100 k Pa) / ( 14.5 psi = 772 k Pa
233.7 K 1.96 gN2 (1 mol N2)/(28.0 g N2) = .0700 mol N2
V * 772 K Pa = 8.314 K Pa * L/ Mol * K * 233.7 * 0.0700 mol N2
0.176 L
f. At what temperature will 82.5g of CO2 produce a pressure of 258kPa in a 102L container?
82.5 G CO2 * (1 mol CO2)/( 44.0 g CO2) = 1.88 mol CO2
258 k Pa * 102 L = 8.314 k Pa * L / mol * K * 1.88 mol CO2 * T
_______
1720
K
g. 42.8 mL of gas are collected over water at 25.6oC, with an atmospheric pressure of 745mmHg. You will
need to look up the vapor pressure of water at that temperature. i. What volume would the gas have at SATP?
(720 mm Hg)(42.8 cm^3)/(298.75 K) = 750.1 mm HG * V/ 298.15 K
_
41.0
cm3
0.00165
mol
____
ii. How many moles of gas is it?
720 mm Hg * 0.0428 L = 62.36 mm Hg *L/mol *k * n *298.75
___
h What volume would be occupied by 0.00358 mol of gas collected over water at 23oC , atmospheric pressure
of 105kPa?
V * 102 K Pa = 0.00358 mol * 296 K * 9.314 K Pa *L/mol * K
0.0864
L