Tag: substances, objects and energy

The three states of matter are classified on the basis of differences of certain physical properties such as physical existence; solids are physically hard, they have fixed shape and size. Liquids do not have any fixed shape and size, they changed according to the shape of beakers in which they are placed. Gases do not have a fixed shape or volume.

The spaces between the particles of gas are more so they can mix into each other very easily. 

Fluids are the substances that can flow easily so gas and liquid are the states which flow easily.

The forces of attraction are strongest in solids, followed by liquids and the weakest in gases.oxygen is a gas, water is a liquid and sugar is a crystalline solid. 

Coal and petroleum are commonly called fossil fuels.
Fuels such as coal, oil and natural gas were formed over millions of years from organic matter like plankton, plants and other life forms. Over time, sand, sediment and rock buried the organic matter and it eventually formed large quantities of fuels. These underground resources, known as fossil fuels, are still the primary fuel source for electricity, heating and powering vehicles around the globe.
There are three major forms of fossil fuels: coal, oil and natural gas. All three were formed many hundreds of millions of years ago hence the name fossil fuels. The age they were formed is called the Carboniferous Period. It was part of the Paleozoic Era. "Carboniferous" gets its name from carbon, the basic element in coal and other fossil fuels.

Fossil fuels are mainly comprised of hydrocarbons. Energy is trapped in the form of chemical energy. When fossil fuels are burnt, chemical energy is converted into heat energy.

Coal is a fossil fuel. Once it is burnt, it turns to ashes and can never be used again.

Hydroelectric energy, also referred to as hydroelectricity or hydropower, is the use of moving water to produce electricity. This power is generated by converting the kinetic energy of flowing water into mechanical and then electrical energy. This process involves the use of turbines, which consist of a set of blades. The moving water flows over the blades, causing them to turn. The blades are connected to a rotating drive shaft. The mechanical energy of the drive shaft is transferred to a generator through a gearbox. The generator uses the mechanical energy of the drive shaft to move an electric conductor (typically coils of copper wire) through a magnetic field, which causes electrons to flow through the conductor, generating electricity. The electricity is then fed into the electrical grid to be used in homes, businesses, and by industry.
Hence, the statement is true.

Answer is A.

It is because they are actually fossils. They are made of dead and decay matter buried under the earth for many years. The dead and decaying matter under great amount of pressure and temperatures turn into fossils and they both are used as fuels so it is called fossil fuels.
The fossil fuels we use today are actually formed from plants and animals that existed hundreds of millions of years ago. The reason there is a lot of concern surrounding the expenditure of these resources is because most of what we use today from fossil fuels, such as oil and coal are being depleted much faster than they can be formed, so there is a limited amount available.
Hence, the statement is true.