4. In which process does the changing of a liquid into gas, takes place below the boiling point of a substance?
a. Freezing
b. Melting
C. Evaporation
d. Condensation
5. During which process, does a gas changes into a liquid?
a. Boiling
b. Melting
C. Cooling
d. None of these
6. Which of the following is incompressible?
a. Water
b. Oxygen
C. Stone
d. Cotton ball
Answers
Answer:
4.evaporation, 5.cooling, 6.water
A solid is like a liquid in that particles are in contact with each other. Solids are unlike liquids in that the intermolecular forces are strong enough to hold the particles in place. At low enough temperatures, all substances are solids (helium is the lone exception), but the temperature at which the solid state becomes the stable phase varies widely among substances, from 20 K (−253°C) for hydrogen to over 3,900 K (3,600°C) for carbon.
The solid phase has several characteristics. First, solids maintain their shape. They do not fill their entire containers like gases do, and they do not adopt the shape of their containers like liquids do. They cannot be easily compressed like gases can, and they have relatively high densities.
Solids may also demonstrate a variety of properties. For example, many metals can be beaten into thin sheets or drawn into wires, while compounds such as NaCl will shatter if they are struck. Some metals, such as sodium and potassium, are rather soft, while others, such as diamond, are very hard and can easily scratch other substances. Appearances differ as well: most metals are shiny and silvery, but sulfur (a nonmetal) is yellow, and ionic compounds can take on a rainbow of colours. Solid metals conduct electricity and heat, while ionic solids do not. Many solids are opaque, but some are transparent. Some dissolve in water, but some do not. Figure 10.12 “Properties of Solids” shows two solids that exemplify the similar and dissimilar properties of solids.