Moderate

The gases become non-ideal at ________________?

Correct answer: D. Low temperature and high pressure

  • A. High temperature and high pressure
  • B. Low temperature and low pressure
  • C. High temperature and low pressure
  • D. Low temperature and high pressure

Explanation

At low temperature, intermolecular attractions become important, and at high pressure, gas molecules are forced close together so their own volume matters. These effects cause the greatest departure from ideal behaviour at low temperature and high pressure. The likely mistake is choosing high temperature and high pressure because high pressure alone promotes non-ideal behaviour, but high temperature reduces it.

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About Real and Ideal Gases

An ideal gas is modelled as particles with negligible volume and no intermolecular attraction, obeying Boyle's, Charles's and Avogadro's laws through PV = nRT. Real gases deviate from this behaviour, especially at high pressure and low temperature, because particle volume and attractive forces matter; the van der Waals equation explains these corrections.

Practise Gases

443 free Gases MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.

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