Advertisements
Advertisements
प्रश्न
In what way real gases differ from ideal gases.
Advertisements
उत्तर
- Ideal gases are the gases that obey gas laws or gas equation PV = nRT.
- Real gases do not obey gas equation. PV = nRT.
- The deviation of real gases from ideal behaviour is measure in terms of a ratio of PV to nRT. This is termed as compression factor (Z). Z = `"PV"/"nRT"`
- For ideal gases Z = 1.
- For real gases Z > 1 or Z < 1. For example, at high-pressure real gases have Z >1 and at intermediate pressure Z < 1.
- Above the Boyle point Z > 1 for real gases and below the Boyle point, the real gases first show a decrease for Z, reach a minimum and then increase with the increase in pressure.
- So, it is clear that at low pressure and high temperature, the real gases behave as ideal gases.
APPEARS IN
संबंधित प्रश्न
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?
Explain whether a gas approaches ideal behavior or deviates from ideal behaviour if the temperature is raised while keeping the volume constant.
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
Value of universal gas constant (R) is same for all gases. What is its physical significance?
Compressibility factor, Z, of a gas is given as Z = `(pV)/(nRT)`. What is the value of Z for an ideal gas?
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.
Choose the correct option for the total pressure (in atm.) in a mixture of 4g \[\ce{O2}\] and 2g \[\ce{H2}\] confined in a total volume of one litre at 0°C is ______.
[Given R = 0.082 L atm mol−1K−1, T = 273 K]
