At 1.00 km above sea level,the atmospheric pressure is 675 mm Hg and the temperature is 282 K.If nitrogen comprises 78.1% (mole percent)of air,what is the density of nitrogen at this height?

Question

Quizplus · Accepted Answer

To find the density of nitrogen, we need to use the ideal gas law: PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature.

First, we need to find the partial pressure of nitrogen:
P_nitrogen = 0.781 * 675 mm Hg = 527.775 mm Hg

Next, we need to convert the pressure to atm and the temperature to Kelvin:
P_nitrogen = 527.775 mm Hg * 1 atm/760 mm Hg = 0.69424 atm
T = 282 K

We can now solve for the number of moles of nitrogen:
n = (P*V)/(R*T)

We can assume that the volume is 1 L (since the question asks for density), and the gas constant for atm and L is 0.08206 L atm/(mol K). Therefore:
n = (0.69424 atm * 1 L)/(0.08206 L atm/(mol K) * 282 K)
n = 0.0296 mol

Finally, we can calculate the density of nitrogen:
density = (n * molecular weight)/(volume)
The molecular weight of nitrogen is 28 g/mol. Therefore:
density = (0.0296 mol * 28 g/mol)/1 L
density = 0.8288 g/L

Therefore, the best choice is C, which is closest to our calculated answer of 0.8288 g/L.

At 100 Km Above Sea Level,the Atmospheric Pressure Is 675 Mm