U-Science-Gr8-Unit2-PBT-CBT (2020-21) Question: 1-10
Different arrangements of atoms are shown in the figure below.
8
Key
. - hydrogen
O = oxygen
O carbon
8
Figure 1
Figure 3
808
ag
808
OS SO
ag
cs
os
808 308
80
808
as
80
Figure 2
Figure 4
Which figure represents a mixture?
Figure 1
Figure 2
Figure 3
Figure 4

Figure 3

Explanation:

A mixture is a substance made up of two or more different kind of atoms arranged in such a way that they are not chemically linked or joined. This accounts for the reason a mixture can be separated easily. In the figures attached as an image in this question:

- Figure 1 represents an element because it is made up of only hydrogen atoms chemically bonded together to form a molecule.

- Figure 2 represents a compound because it contains hydrogen and carbon atoms chemically joined together.

- Figure 3 represents a MIXTURE because it contains the oxygen and carbon atoms, which are not chemically joined to one another. As seen in the image, the oxygen atoms are not joined to the carbon atoms.

- Figure 4 represents a compound because it contains oxygen and hydrogen atoms chemically bonded together.

a fossil fuel is a fuel formed by natural processes, such as anaerobic decomposition of buried dead organisms, containing energy originating in ancient photosynthesis.[1] the age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years.[2] fossil fuels contain high percentages of carbon and include petroleum, coal, and natural gas.[3] other commonly used derivatives include kerosene and propane. fossil fuels range from volatile materials with low carbon to hydrogen ratios like methane, to liquids like petroleum, to nonvolatile materials composed of almost pure carbon, like anthracite coal. methane can be found in hydrocarbon fields either alone, associated with oil, or in the form of methane clathrates.

the theory that fossil fuels formed from the fossilized remains of dead plants by exposure to heat and pressure in the earth's crust over millions of years was first introduced by andreas libavius "in his 1597 alchemia [alchymia]" and later by mikhail lomonosov "as early as 1757 and certainly by 1763".[4] the first use of the term "fossil fuel" was by the german chemist caspar neumann, in english translation in 1759.[5]

in 2017 the world's primary energy sources consisted of petroleum (34%), coal (28%), natural gas (23%), amounting to an 85% share for fossil fuels in primary energy consumption in the world.[6] non-fossil sources in 2006 included nuclear (8.5%), hydroelectric (6.3%), and others (geothermal, solar, tidal, wind, wood, waste) amounting to 0.9%.[7] world energy consumption was growing at about 2.3% per year. in 2015 about 18% of worldwide consumption was from renewable sources.[8]

above statement is not a true statement about the open ocean because the open ocean has low levels of nutrients. most of the photosynthetic activity on earth occurs in the open ocean within the photic zone. organisms in the deep ocean are exposed to frigid temperatures and total darkness but it does not begin at the low-tide mark.