51. The temperature above which a liquid can no longer exist as a liquid, regardless of pressure, is known as:

a) Boiling point
b) Freezing point
c) Critical point
d) Triple point
Answer: c) Critical point

52. The change in volume of a liquid due to temperature changes is an example of:

a) Surface tension
b) Thermal expansion
c) Capillarity
d) Viscosity
Answer: b) Thermal expansion

53. The strong forces between the molecules of which substance give it a high surface tension?

a) Ethanol
b) Water
c) Mercury
d) Acetone
Answer: b) Water

54. The property of a liquid to resist external forces and maintain its shape is called:

a) Viscosity
b) Surface tension
c) Density
d) Capillarity
Answer: b) Surface tension

55. The process where molecules from a solid phase enter the gas phase without passing through the liquid phase is:

a) Evaporation
b) Condensation
c) Sublimation
d) Melting
Answer: c) Sublimation

56. In a crystalline solid, the repeating unit of the structure is called a:

a) Molecule
b) Lattice
c) Unit cell
d) Cluster
Answer: c) Unit cell

57. The transition from a gas to a liquid occurs through the process of:

a) Condensation
b) Evaporation
c) Sublimation
d) Melting
Answer: a) Condensation

58. The ability of a liquid to flow easily is known as:

a) Viscosity
b) Surface tension
c) Capillarity
d) Density
Answer: a) Viscosity

59. In a liquid, the particles are:

a) Fixed in place and vibrate
b) Closely packed and vibrate
c) Free to move and widely spaced
d) Moving rapidly and spaced widely
Answer: b) Closely packed and vibrate

60. The phenomenon where a liquid rises in a narrow tube due to intermolecular forces is called:

a) Surface tension
b) Capillarity
c) Viscosity
d) Density
Answer: b) Capillarity