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प्रश्न
Value of universal gas constant (R) is same for all gases. What is its physical significance?
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उत्तर
Unit of R depends on the units of p, V and T are measured, We know, `R = (pV)/(nT)`
Now, let's say, the pressure is measured in Pascal, per mole volume is measured in m3 and temperature is measured in Kelvin, then. Units of ‘R’ are Pa m3K–1 mol–1. Also, R is work done per mole per kelvin. It’s unit is J K–1 mol–1 (Joule is the unit of work done).
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संबंधित प्रश्न
Calculate the volume occupied by 8.8 g of CO2 at 31.1°C and 1 bar pressure. R = 0.083 bar L K–1 mol–1.
Which of the following is the correct expression for the equation of state of van der Waals gas?
Which of the following diagrams correctly describes the behaviour of a fixed mass of an ideal gas? (T is measured in K)
25 g of each of the following gases are taken at 27°C and 600 mm Hg pressure. Which of these will have the least volume?
In what way real gases differ from ideal gases.
Explain whether a gas approaches ideal behavior or deviates from ideal behaviour if more gas is introduced into the same volume and at the same temperature.
A plot of volume (V) versus temperature (T) for a gas at constant pressure is a straight line passing through the origin. The plots at different values of pressure are shown in Figure. Which of the following order of pressure is correct for this gas?
Under which of the following two conditions applied together, a gas deviates most from the ideal behaviour?
(i) Low pressure
(ii) High pressure
(iii) Low temperature
(iv) High temperature
If 1 gram of each of the following gases are taken at STP, which of the gases will occupy (a) greatest volume and (b) smallest volume?
\[\ce{CO, H2O, CH4 , NO}\]
Compressibility factor, Z, of a gas is given as Z = `(pV)/(nRT)`. What is the value of Z for an ideal gas?
Compressibility factor, Z, of a gas is given as Z = `(pV)/(nRT)`. For real gas what will be the effect on value of Z above Boyle’s temperature?
Pressure versus volume graph for a real gas and an ideal gas are shown in figure. Answer the following questions on the basis of this graph.
(i) Interpret the behaviour of real gas with respect to ideal gas at low pressure.
(ii) Interpret the behaviour of real gas with respect to ideal gas at high pressure.
(iii) Mark the pressure and volume by drawing a line at the point where real gas behaves as an ideal gas.
Match the following graphs of ideal gas with their co-ordinates:
| Graphical representation | x and y co-ordinates |
(i)  |
(a) pV vs. V |
(ii)  |
(b) p vs. V |
(iii)  |
(c) p vs. `1/V` |
Assertion (A): At constant temperature, pV vs V plot for real gases is not a straight line.
Reason (R): At high pressure all gases have \[\ce{Z}\] > 1 but at intermediate pressure most gases have \[\ce{Z}\] < 1.
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In van der Waal's equation for the real gas, the expression for the net force of attraction amongst the gas molecules is given by:
