A gas in equilibrium has uniform density and pressure throughout its volume . This is strictly true only if there are no external influences. A gas column under gravity, for example, does not have uniform density (and pressure). As you might expect, its density decreases with height. The precise dependence is given by the so-called law of atmospheres

A gas in equilibrium has uniform density and pressure throughout its volume . This is strictly true only if there are no external influences. A gas column under gravity, for example, does not have uniform density (and pressure). As you might expect, Read More …

From a certain apparatus, the diffusion rate of hydrogen has an average value of 28.7 cm3 s-1 . The diffusion of another gas under the same conditions is measured to have an average rate of  7.2 cm3 s-1 . Identify the gas. [Hint: Use Graham’s law of diffusion:   R1 / R2 = (M1 /M2)1/2 , where  R1 , R2 are diffusion rates of gases 1 and 2, and  M1 and M2 their respective molecular masses. The law is a simple consequence of kinetic theory.]

From a certain apparatus, the diffusion rate of hydrogen has an average value of 28.7 cm3 s-1 . The diffusion of another gas under the same conditions is measured to have an average rate of  7.2 cm3 s-1 . Identify the gas. Read More …

A metre long narrow bore held horizontally (and closed at one end) contains a 76 cm long mercury thread, which traps a 15 cm column of air. What happens if the tube is held vertically with the open end at the bottom?

A metre long narrow bore held horizontally (and closed at one end) contains a 76 cm long mercury thread, which traps a 15 cm column of air. What happens if the tube is held vertically with the open end at the bottom?

Estimate the mean free path and collision frequency of a nitrogen molecule in a cylinder containing nitrogen at 2.0 at m and temperature 17 oC. Take the radius of a nitrogen molecule to be roughly 1.0 Å .Compare the collision time with the time the molecule moves freely between two successive collisions (Molecular mass of  N2 = 28. 0 u ).

Estimate the mean free path and collision frequency of a nitrogen molecule in a cylinder containing nitrogen at 2.0 at m and temperature 17 oC. Take the radius of a nitrogen molecule to be roughly 1.0 Å .Compare the collision time with Read More …

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). Do the vessels contain equal number of respective molecules? Is the root mean square speed of molecules the same in the three cases? If not, in which case is v rms the largest?

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). Do the vessels contain equal number of respective molecules? Is the root Read More …

Estimate the average thermal energy of a helium atom at (i) room temperature(27 ×C), (ii) the temperature on the surface of the Sun (6000 K), (iii) the temperature of 10 million Kelvin (the typical core temperature in the case of a star).

Estimate the average thermal energy of a helium atom at (i) room temperature(27 ×C), (ii) the temperature on the surface of the Sun (6000 K), (iii) the temperature of 10 million Kelvin (the typical core temperature in the case of a star).

An oxygen cylinder of volume 30 litres has an initial gauge pressure of 15 atm and a temperature of 27oC . After some oxygen is withdrawn from the cylinder, the gauge pressure drops to 11 atm and its temperature drops to17 oC . Estimate the mass of oxygen taken out of the cylinder (  R×8.31 J mol-1 K-1 , molecular mass of  O2 × 32 u ).

An oxygen cylinder of volume 30 litres has an initial gauge pressure of 15 atm and a temperature of 27oC . After some oxygen is withdrawn from the cylinder, the gauge pressure drops to 11 atm and its temperature drops to17 oC Read More …

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