Advertisements
Advertisements
Question
Estimate the total number of air molecules in a room of a capacity of 25 m3 at a temperature of 27°C.
Advertisements
Solution
T = 27°C + 273 = 300 K
kB = 1.38 × 10−23 J K−1
V = 25 m3
As Boltzmann’s Constant, kB = `"R"/"N"` ⇒ R = kBN
Now, PV = nRT = nkBNT
The number of molecules in the room,
nN = `"PV"/("k"_"B""T") = (1.013 xx 10^5 xx 25)/(1.38 xx 10^-23 xx 300)`
= `(25.325 xx 10^5)/(414 xx 10^-23)`
= 0.06117 × 1028
= 6.117 × 1026 molecules
nN = 6.1 × 1026 molecules
APPEARS IN
RELATED QUESTIONS
Determine the pressure of nitrogen at 0°C if the density of nitrogen at N.T.P. is 1.25 kg/m3 and R.M.S. speed of the molecules at N.T.P. is 489 m/s.
Two identically sized rooms A and B are connected by an open door. If the room A is air-conditioned such that its temperature is 4°C lesser than room B, which room has more air in it?
The ratio γ = `"C"_"p"/"C"_"v"` for a gas mixture consisting of 8 g of helium and 16 g of oxygen is ____________.
The following graph represents the pressure versus number density for an ideal gas at two different temperatures T1 and T2. The graph implies

If 1020 oxygen molecules per second strike 4 cm2 of wall at an angle of 30° with the normal when moving at a speed of 2 × 103 ms−1, find the pressure exerted on the wall. (mass of one oxygen atom = 2.67 × 10−26 kg)
According to the assumptions made in the kinetic theory of gases, when two molecules of a gas collide with each other, then ______.
The average force applied on the walls of a closed container depends as 'Tx', where 'T' is the temperature of an ideal gas. The value of 'x' is ______.
Does an ideal gas exist in practice?
Temperature remaining constant, if you double the number of molecules in a box, the pressure will ______.
The velocities of five molecules are 2 m/s, 3 m/s, 4 m/s, 5 m/s and 6 m/s. Find the root mean square velocity of molecules.
