<span>Hydroelectric energy uses the movement of water to spin a turbine and produce electricity. Coal is a fossil fuel that is burned as an energy source, which results in emissions such as carbon dioxide, nitrogen, and sulfur. Coal use is associated with waste products both from the mining process to acquire the coal and also from the actual use of coal itself. Hydroelectric energy does not involve waste, but does pose potential problems to waterways. Coal use is more common than the use of hydroelectric energy.</span>
Answer:
Combining the two clear colorless liquids is a chemical change.
Explanation:
Because a different solid substance is formed. Tell students that a precipitate is an insoluble solid that forms when two solutions are combined and react chemically. Insoluble means that the solid will not dissolve.
<span>The correct answer is d. The reaction releases more energy than it absorbs. An example of an exothermic reaction is fire. Connecting the carbon atoms in wood with the oxygen in the air causes flames and gives of heat and light.</span>
