what is the hottest atmospheric layer?

One litter of air at atmospheric pressure and 25C is held in a flask.the pressure of oxygen in the flask is 0.201 atm(20.4kpa).the concentration of oxygen in the flask ,in mole per litter is
A 8.2 B 0.12 C0.098 D0.0082 请问选哪个 然后为什么

求解几道英文的化学题，急！
（1）In dry atmospheric air, the four most abundant components are N2,
X = 0.808; O2, X = 0.1915; Ar, X = 9.34x10-5; and
CO2, X = 4.066x10-4. Calculate the partial pressure of
O2, in torr, under standard atmospheric conditions.（2）Oxygen gas can be generated by heating KClO3 in the presence of
some MnO2.2KClO3 → 2KCl + 3O2
If all the KClO3 in a mixture containing 2.46 g KClO3
and 0.35 g MnO2 is decomposed, how many liters of O2 gas
will be generated at T = 29.0°C and P = 752.6 torr?（3）A pressurized can of whipped cream has an internal pressure of 1.175 atm at
26°C. If it is placed in a freezer at -20°C, what is the new value for its
internal pressure (in atmospheres)?（4）In dry atmospheric air, the four most abundant components are N2,
X = 0.808; O2, X = 0.1915; Ar, X = 9.34x10-5; and
CO2, X = 4.066x10-4. Calculate the partial pressure of
N2, in torr, under standard atmospheric conditions.（5）Elemental analysis is performed on an organic liquid with a fishy odor.
Vaporization of 240.0 mg of the compound in a 180 mL bulb at 170°C gives a
pressure of 435.0 torr. What is the molar mass of this compound?（6）A mouse is placed in a sealed chamber with air at 762.0 torr. This chamber is
equipped with enough solid KOH to absorb any CO2 and H2O
produced by the mouse. The gas volume in this chamber is measured to be exactly
2.50 L, the temperature is held constant at 297 K. After two hours the pressure
inside the bottle falls to 723.1 torr. What mass of oxygen has the mouse
consumed?急，求答案！

一道英文化学题
The density of air at ordinary atmospheric pressure and 25°C is 1.19g/L.What is the mass, in kilograms, of the air in a room that measures 10.0*14.0*10 ft? Express your answer using two significant figures.

科学常识部分7777
1.atmospheric ozone is beneficial to the human body because( )
A.absorption of ultraviolet B.absorption of infrared
C.stop the microwave radiation D.prevention of acid rain

英语翻译
Typical atmospheric temperatures achieved within the reaction vessel when in the preheating regime are between 430 to 540 ℃.