The fourth (last) one in 2-8-8-2.
Answer:
The correct answer is D
Explanation:
Many substances hold their molecules together in the liquid or solid bosom. This is due, in addition to the pressure and temperature conditions, by the forces of Van der Waals. These are still produced in nonpolar molecules by the movement of electrons through the molecules; in extremely short periods of time, their electrons "charge" towards one end of the molecule, producing small dipoles and keeping the molecules very close to each other.
Answer: When coal is burned, chemical potential energy is transformed into thermal energy, light energy, and sound energy. Only the thermal energy is used for electricity production. Light and sound energy dissipate into the environment, immediately reducing efficiency.
Hope this helps.
Answer:
Gases are easily compressed. We can see evidence of this in Table 1 in Thermal Expansion of Solids and Liquids, where you will note that gases have the largest coefficients of volume expansion. The large coefficients mean that gases expand and contract very rapidly with temperature changes. In addition, you will note that most gases expand at the same rate, or have the same β. This raises the question as to why gases should all act in nearly the same way, when liquids and solids have widely varying expansion rates.
The answer lies in the large separation of atoms and molecules in gases, compared to their sizes, as illustrated in Figure 2. Because atoms and molecules have large separations, forces between them can be ignored, except when they collide with each other during collisions. The motion of atoms and molecules (at temperatures well above the boiling temperature) is fast, such that the gas occupies all of the accessible volume and the expansion of gases is rapid. In contrast, in liquids and solids, atoms and molecules are closer together and are quite sensitive to the forces between them.
