Question

1Q)

A nitrogen sample occupies 220. mL at STP. If the same sample were collected over water at 25°C and 600. torr, what would be the volume of the gas sample? (Assume that vapor pressure of water at 25°C is 23.8 torr.)

Volume =....... mL

2Q)

A number of compounds containing the heavier noble gases, and especially xenon, have been prepared. One of these is xenon hexafluoride (XeF₆), which can be prepared by heating a mixture of xenon and fluorine gases. XeF₆ is a white crystalline solid at room temperature and melts at about 325 K. A mixture of 0.0600 g of Xe and 0.0223 g of F₂ is sealed into a 100.0-mL bulb. The bulb contains no air or other gases. The bulb is heated, and the reaction above goes to completion. Then, the sealed bulb is cooled back to 20.0°C. What will be the final pressure in the bulb, expressed in torr?

......torr

3Q)

Liquid oxygen can be produced for use as a rocket fuel by cooling dry air to -183°C, where the O₂ condenses. How many liters of dry air at 25°C and 750 torr would need to be processed to produce 120 L of liquid O₂ at -183°C? The mole fraction of oxygen in dry air is 0.21, and the density of liquid oxygen is 1.14 g/mL.

..........L

4Q)

Clouds of hydrogen molecules have been detected deep in interstellar space. It is estimated that these clouds contain about 1 × 10¹⁰ hydrogen molecules per m³ and have a temperature of just 20 K. Using these data, find the approximate pressure in such a cloud.

......atm

Answer 1