On increasing the temperature of solids, the kinetic energy of the particles ________.
- A.First increases and then decreases
- B.Is constant
- C.Increases
- D.Decreases
Correct answer
Explanation
The correct answer is C, increases. Temperature is a measure of the average kinetic energy of the particles of a substance, in a solid as in a gas: in a solid the particles are held in fixed positions but vibrate about them, and heating makes the vibrations faster and wider, so the average kinetic energy rises with temperature. If enough energy is supplied, the vibrations overcome the forces holding the lattice together and the solid melts. A, first increases and then decreases is wrong because there is no temperature at which further heating reduces particle energy. B, is constant would mean that heating changes nothing, which contradicts the very definition of temperature; the energy does stay constant only while a solid is actually melting, and then the heat goes into breaking bonds, not into kinetic energy. D, decreases is the opposite of the truth and would mean that cooling speeds particles up.
Read the full article: Gas Laws and Kinetic Theory of Gases: Formulas and PYQs
Practice Questions
View allBoyle's law states that at constant temperature, the volume of a fixed mass of gas is
- A.Directly proportional to its pressure
- B.Inversely proportional to its pressure
- C.Independent of its pressure
- D.Proportional to the square of its pressure
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Boyle's law, established in 1662, says that for a fixed mass of gas at constant temperature the product of pressure and volume stays constant, so doubling the pressure halves the volume.
Read the full explanation →A hot air balloon rises because warm air
- A.Becomes denser than the surrounding air
- B.Expands and becomes less dense than the surrounding air
- C.Loses its mass on heating
- D.Has a lower specific heat than cold air
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By Charles's law the volume of a fixed mass of gas at constant pressure is proportional to its absolute temperature, so heating the air inside the envelope makes it expand; some of it escapes from the open mouth, the mass of air left inside falls, its density becomes lower than…
Read the full explanation →Absolute zero of temperature is equal to
- A.0 degrees Celsius
- B.-100 degrees Celsius
- C.-273.15 degrees Celsius
- D.-373.15 degrees Celsius
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Extending the straight line of Charles's law backwards shows that the volume of an ideal gas would become zero at minus 273.15 degrees Celsius, and this point is taken as the zero of the kelvin or absolute scale, at which molecular motion carries its least possible energy.
Read the full explanation →In the ideal gas equation PV = nRT, the value of the universal gas constant R in SI units is
- A.0.0821
- B.8.314
- C.1.987
- D.6.022
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In SI units the universal gas constant is 8.314 joule per mole per kelvin, obtained by multiplying the Boltzmann constant by the Avogadro number.
Read the full explanation →The volume occupied by one mole of an ideal gas at 273.15 K and one atmosphere pressure is about
- A.11.2 litres
- B.22.4 litres
- C.44.8 litres
- D.1 litre
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Substituting one mole, 273.15 kelvin and one atmosphere in the ideal gas equation gives a volume of 22.4 litres, the molar volume at standard temperature and pressure, and this is the figure used in mole calculations; with the modern standard pressure of one bar the value works out to about…
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