Question

# Chapter 5- Gases 24. As weather balloons rise from the earth's surface, the pressure of th...

Chapter 5- Gases

24. As weather balloons rise from the earth's surface, the pressure of th atmosphere becomes less, tending to cause the volume of the balloons to exand. However, the temperature is much lower in the upper atmosphere that at sea level. Would this temperature effect tend to make such a balloon expand or contract? Weather balloons do, in fact, expand as they rise. What does this tell you?

37. Freon-12 (CF2Cl2) is commonly used as the refrigerant in central home air conditioners. The system is initially charged to a pressure of 4.8 atm. Express this pressure in eac of the following units (1atm = 14.7 psi).

A: mm Hg

B: torr

C: Pa

D:psi

38. A gauge on a compressed gas cylinder reads 2200 psi (pounds per square inch; 1 atm = 14.7psi) Express this pressure in eahc of the following units.

A: standard atmospheres

B: megapascals (MPa)

C: torr

39. A sealed-tube manometer can be used to measure pressures belwo atmospheric pressure. The tube above the mercury is evacuated. When there is a vacuum in the flask, the mercury levels in both arms of the U-tube are eual. If a gaseous sampe is introduced into the flask, the merury levels are different. The difference in h is a measure of the pressure of the gas inside the flask. If h is equal to 6.5 cm, calculate the pressure in the flask in torr, pascals, and atmospheres.

43. A particular balloon is designed by its manufacturer to be inflated to a volume of no more than 2.5L. If the balloon is filled wih 2.0L of helium at sea level, is released and rises to an altitudeat which the atmospheric pressure is only 500. mm Hg, will the balloon burst? (Assume temperature is constant)

47. Complete the following table for an ideal gas.

 P(atm) V (L) n (mol) T 5.00 2.00 155C 0.300 2.00 155K 4.47 25.0 2.01 2.25 10.5 75C

65. Consider the following reaction:

4Al(s) + 3O2(g)----------- 2 Al2O3 (s)

It takes 2.00 L of pure oxygen gas at STP to react completely with a certain samle of aluminum. What is the mass of aluminum reacted?

81. Determine the partiral pressure of each of the gases below. (1 atm.)

He- 5

Ne- 3

Ar- 2

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