Question #25bda
1 Answer
(c)
Explanation:
We're asked to find the mass of
Every time you're given three of the four basic characteristics of a gas (pressure, volume, temperature, and/or moles), you'll be using the idealgas equation:
where
#P# is the pressure of the gas, expressed in atmospheres (#"atm"# ).
Since the pressure in this case is given in pascals, we have to convert this to atmospheres, using the conversion factor
#1# #"atm" = 101,325# #"Pa"#
#2.0 xx 10^7# #cancel("Pa")((1"atm")/(101,325cancel("Pa"))) = color(red)(197# #color(red)("atm"#

#V# is the volume occupied by the gas, expressed in liters, which is given as#color(orange)(1000)# #color(orange)("L")# 
#n# is the quantity of gas present, in moles, which is what we must find in order to calculate the mass of oxygen present 
#R# is called the universal gas constant, and is equal to#color(purple)(0.08206 ("L · atm")/("mol · K")# 
#T# is the absolute temperature of the system, "absolute" indicating that the temperature is in units of Kelvin,#"K"#
Since our given temperature is in degrees Celsius, we have to convert this to Kelvin using the formula
#"K" = ""^"o""C" + 273#
#"K" = 27^"o""C" + 273 = color(green)(300)# #color(green)("K")#
Now that we have all our necessary units, let's use the idealgas equation to find the number of moles of
Now that we know the moles of gas present, we can use the molar mass of
Lastly, let's convert this to kilograms:
Thus, the correct answer is (c).