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Unformatted text preview: Chemistry 520 Midterm Exam, Winter Quarter 7:30  9:00 PM, 7 February 2008 NAME Useful Constants R = 8 . 314 JK 1mol 1 k B = 1 . 381 × 10 23 JK 1 e = 1 . 1602 × 10 19 C m e = 9 . 11 × 10 31 kg N = 6 . 022 × 10 23 mol 1 = 8 . 854 × 10 12 C 2 N 1 m 2 c = 2 . 998 × 10 8 ms 1 h = 6 . 626 × 10 34 Js 1 J = 1 kg m 2 s 2 1 amu = 1.661 × 10 27 kg 1 Pa = 1 J m 3 1. [10 points] Source: Chang, 2.39 A mixture of helium and neon weighing 5.50 g occupies a volume of 6.80 L at 300 K and 1.00 atm. Calculate the composition of the mixture in mass percent. 2. [10 points] Source: Chang, 3.5 A square box contains He at 25 ◦ C. If the atoms are colliding with the walls perpendicularly (at 90 ◦ ) at the rate of 4 . × 10 22 times per second, calculate the force and the pressure exerted on the wall given that the area of the wall is 100 cm 2 and the speed of the atoms is 600 m s 1 . 3. [10 points] Source: Chang, 3.28 Suppose that helium atoms in a sealed container all start with the same speed, 2 . 74 × 10 4 cm s 1 . The atoms are then allowed to collide with one another until the Maxwell distribution is established. What is the temperature ofthen allowed to collide with one another until the Maxwell distribution is established....
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 Spring '08
 GRANDINETTI
 Chemistry, Physical chemistry, pH, Kinetic theory

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