Which of the following is true about pressure for an ideal gas at -273 degrees Celsius?
Correct answer: D. P = 0 atm
- A. P = 1 atm
- B. P = 2 atm
- C. P = 3 atm
- D. P = 0 atm
Explanation
Absolute zero is minus 273 degrees Celsius, and extrapolating a pressure against temperature graph for a fixed volume of ideal gas back to that point gives zero pressure, since molecular motion reaches its minimum and no collisions occur with the walls. No real gas actually reaches this, because every gas liquefies first, so the value is an extrapolation rather than an observation. It is exactly how the absolute scale is defined.
This question appeared on the UHS MDCAT 2025 paper, which you can sit online with every answer explained.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? support@testustad.com
About Absolute Zero
Absolute zero is 0 K, equal to −273.15°C, the lowest theoretical temperature on the Kelvin scale. The topic covers the relationship between temperature and molecular motion, the extrapolation of gas volume or pressure to zero, and why absolute zero cannot be reached experimentally, although particles retain quantum zero-point energy.
Practise Gases
443 free Gases MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Chemistry questions like this
Chemistry is on 14 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Absolute Zero questions
Absolute zero is the temperature at which
Charles's law predicts that a gas cooled at constant pressure would reach zero volume at
Which of the following is known as absolute zero?
If a graph is plotted between temperature on x-axis and volume on y-axis for 1 mole of gas then we get straight line which cuts the temperature exis at________________?
What is the temperature at which the volume of gas is said to be zero?
A graph between volume and temperature gives a straight line which cuts the temperature axis at: