For an ideal gas, which one of the following statements does not hold true?
- A.The speed of all gas molecules is same.
- B.The kinetic energies of all gas molecules are not same.
- C.The potential energy of the gas molecules is zero.
- D.There is no interactive force between the molecules.
Correct answer
Explanation
The correct answer is A, The speed of all gas molecules is same. In an ideal gas the molecules move with a whole range of speeds, so this statement is false.
The kinetic theory treats an ideal gas as a large number of tiny molecules in random motion that collide elastically with one another and with the walls. Because of these constant collisions, molecules keep gaining and losing speed, and at any moment their speeds are spread out according to the Maxwell–Boltzmann distribution. Only the average kinetic energy is fixed by temperature: it equals (3/2)kT per molecule. The theory also assumes that the molecules do not attract or repel each other except during collisions, so the gas has no potential energy and its internal energy is purely kinetic.
Option B is true because different speeds mean different kinetic energies. Option C is true because with no forces between molecules there is no potential energy. Option D is true because the absence of intermolecular forces is a basic assumption of the ideal gas model.
Exam tip: ideal gas = no intermolecular forces, zero potential energy; average kinetic energy depends only on temperature.
Practice Questions
View allWhich one of the following statements is correct?
- A.Urea is produced in liver.
- B.Urea is produced in blood.
- C.Urea is produced from digestion of starch.
- D.Urea is produced in lung and kidney.
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Liver cells turn the toxic ammonia released from the breakdown of amino acids into urea through the ornithine cycle, also called the urea cycle.
Read the full explanation →Which one of the following is the correct sequence of passage of light in a compound microscope?
- A.Condenser-Objective lens-Eyepiece-Body tube
- B.Objective lens-Condenser-Body tube-Eyepiece
- C.Condenser-Objective lens-Body tube-Eyepiece
- D.Eyepiece-Objective lens-Body tube-Mirror
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Light passes through the condenser to the specimen, is picked up by the objective lens, travels up the body tube and reaches the eye through the eyepiece.
Read the full explanation →Which one of the following statements regarding haemoglobin is correct?
- A.Haemoglobin present in RBC can carry only oxygen but not carbon dioxide.
- B.Haemoglobin of RBC can carry both oxygen and carbon dioxide.
- C.Haemoglobin of RBC can carry only carbon dioxide.
- D.Haemoglobin is only used for blood clotting and not for carrying gases.
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It binds oxygen at its iron-containing haem groups and carries some carbon dioxide on its protein chains. Each haemoglobin molecule has four polypeptide chains and four haem groups, and each haem iron can hold one oxygen molecule, forming oxyhaemoglobin in the lungs.
Read the full explanation →Which one of the following statements regarding histone proteins is correct?
- A.Histones are proteins that are present in mitochondrial membrane.
- B.Histones are proteins that are present in nucleus in association with DNA.
- C.Histones are proteins associated with lipids in the cytosol.
- D.Histones are proteins associated with carbohydrates in the cytosol.
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They are the proteins around which DNA winds to form chromatin in the nucleus of eukaryotic cells. Histones are small basic proteins, rich in the positively charged amino acids lysine and arginine, which attract the negatively charged phosphate groups of DNA.
Read the full explanation →The Hooke's law is valid for
- A.only proportional region of the stress-strain curve
- B.entire stress-strain curve
- C.entire elastic region of the stress-strain curve
- D.elastic as well as plastic region of the stress-strain curve
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Hooke's law says stress is directly proportional to strain, and that holds only up to the proportional limit, where the curve is a straight line.
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