Advertisements
Advertisements
प्रश्न
Estimate the average thermal energy of a helium atom at room temperature (27 °C).
Advertisements
उत्तर
At room temperature, T = 27°C = 300 K
Average thermal energy = `3/2` kT
Where k is Boltzmann constant = 1.38 × 10–23 m2 kg s–2 K–1
`therefore 3/2kT = 3/2 xx 1.38 xx 10^(-38) xx 300`
= 6.21 × 10–21J
Hence, the average thermal energy of a helium atom at room temperature (27°C) is 6.21 × 10–21 J.
संबंधित प्रश्न
An oxygen cylinder of volume 30 litres has an initial gauge pressure of 15 atm and a temperature of 27 °C. After some oxygen is withdrawn from the cylinder, the gauge pressure drops to 11 atm and its temperature drops to 17 °C. Estimate the mass of oxygen taken out of the cylinder (R = 8.31 J mol–1 K–1, molecular mass of O2 = 32 u)
Estimate the total number of air molecules (inclusive of oxygen, nitrogen, water vapour and other constituents) in a room of capacity 25.0 m3 at a temperature of 27 °C and 1 atm pressure
Three vessels of equal capacity have gases at the same temperature and pressure. The first vessel contains neon (monatomic), the second contains chlorine (diatomic), and the third contains uranium hexafluoride (polyatomic).
Is the root mean square speed of molecules the same in the three cases? If not, in which case is vrms the largest?
At what temperature is the root mean square speed of an atom in an argon gas cylinder equal to the rms speed of a helium gas atom at – 20 °C? (atomic mass of Ar = 39.9 u, of He = 4.0 u).
What do you understand by gas?
What is diffusion? Give an example to illustrate it.
Give reasons for the following:
Gas fills the vessel completely in which it is kept.
Choose the correct answer:
The graph of PV vs P for gas is
Name or state the following:
An equation used in chemical calculations which gives a simultaneous effect of changes of temperature and pressure on the volume of a given mass of dry gas
Name or state the following:
The standard pressure of a gas in cm. of mercury corresponding to one atmospheric pressure.
Give reason for the following:
Volumes of gases are converted into s.t.p. conditions and then compared.
Show that for monoatomic gas the ratio of the two specific heats is 5:3.
Show that for diatomic gas the ratio of the two specific heats is 7:5.
The equation of state for 2g of oxygen at a pressure 'P' and temperature 'T', when occupying a volume 'V' will be ______.
Which of the following diagrams (Figure) depicts ideal gas behaviour?
![]() (a) |
![]() (b) |
![]() (c) |
![]() (d) |
A box of 1.00 m3 is filled with nitrogen at 1.50 atm at 300K. The box has a hole of an area 0.010 mm2. How much time is required for the pressure to reduce by 0.10 atm, if the pressure outside is 1 atm.
Cooking gas containers are kept in a lorry moving with uniform speed. The temperature of the gas molecules inside will ______.
At room temperature, a diatomic gas is found to have an r.m.s. speed of 1930 ms-1. The gas is ______.




