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Question
In what way real gases differ from ideal gases.
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Solution
- 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.
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