Answer:
The answer to your question is given below
Explanation:
1. C. 2NaCl + I2 —> 2NaI + Cl2 => C. Single displacement.
From the above equation, we can see that I2 replaces Cl in NaCl to produce NaI. This is simply called a single displacement reaction.
2. E. 2C4H10 + 13O2 —> 8CO2 + 10H2O => E. Combustion.
The above equation shows the burning of Hydrocarbon in the presence of O2. This is simply called Combustion as CO2 and H2O is produced.
3. D 2H2O —> 2H2 + O2 => D. Decomposition.
From the above equation, we can see that a single compound H2O produces two elements H2 and O2. This is simply called a decomposition reaction.
4. A. ZnS + 2HCl —> ZnCl2 + H2S => A. Double Decomposition.
From the above equation, we can see that Cl replaces S in ZnS to produce ZnCl2 and S replaces Cl in HCl to produce H2S. This is simply called double displacement reaction.
5. B. H2 + Br2 —> 2HBr => B. Synthesis.
From the above equation, we can see that two element H2 and Br2 combine to produce a single compound HBr. This is simply called a synthesis reaction.
Answer:
C. As scientists have learned more about chemicals, they have become more aware of their dangers
Explanation:
Chemicals are substances with standard compositions, held together by chemical bonds. Chemicals can exist in different phases such as solid, liquid, and gaseous phases. Over time, with a growing understanding of chemicals, their composition, and their reaction methods, scientists now have a better knowledge of the dangers chemicals can pose. To that effect, they have created standard safety measures for those who have to work with these chemicals.
When these guidelines are strictly adhered to, the chances of suffering accidents, burns, and explosions with these chemicals are significantly reduced.
<span> under extreme heat or pressure
crystallize from magma
precipitate from a solution reaction of hot mixture with water and a dissolved substance</span>
<h2>
Hello!</h2>
The answer is:
The empirical formula is the option B. 
<h2>
Why?</h2>
The empirical formula of a compound is the simplest formula that can be written. On the opposite, the molecular formula involves a variant of the same compound, but it can be also simplified to an empirical formula.
We are looking for a formula that cannot be simplified by dividing the number of molecules/atoms that conforms the compound.
Let's discard option by option in order to find which formula is an empirical formula (cannot be simplified)
A. 
It's not an empirical formula, it's a molecular formula since it can be obtained by multiplying the empirical formula of the same compound.
B.
It's an empirical formula since it cannot be obtained by the multiplication of a whole number and the simplest formula. It's the simplest formula that we can find of the compound.
C. 
It's not an empirical formula, it's a molecular formula since it can be obtained by multiplying the empirical formula of the same compound.
D. 
It's not an empirical formula, it's a molecular formula since it can be obtained by multiplying the empirical formula of the same compound.
Hence, the empirical formula is the option B.
Have a nice day!
<span>The Persian Wars mark an important turning point not only in Greek history but, indeed, in the course of all European civilization. First and foremost, because of its victory Greece was saved from the threat of external rule and could develop on its own. Handed this independence, the Greeks chose to follow a path which forever changed the course of modern life. Without their success in this conflict, they would, no doubt, never have had the liberty, means or conviction to invent, discover or create all they did: not just history but philosophy, science, drama, art, architecture, indeed most of the cornerstones of modern civilization.
Another consequence of this victory, less immediate but equally important, was that it prevented the Persians from dominating the lands to the west of Greece—as noted above, it's likely the fertile fields of Italy and Sicily, not the rough dust of Greece, were the real target of Xerxes' imperial designs—and there a tiny settlement called Rome had just begun to sprout, at that moment hardly a dot on the map, but it would later develop into a crucial player in the history of the West. Rome won freedom, too, in the Persian Wars, without ever fielding a single fighter. It's impossible to imagine how vastly different our world would be if Persia had conquered or exterminated the Romans before they'd ever had a chance to grow.
Thus, the Greeks laid the groundwork for later Western culture, and Herodotus the foundation for understanding it. If so many of his facts look suspect or even prove incorrect, if he sometimes seems to set speculation and scandal over sober criticism and science, before condemning him we should recall that he founded this entire enterprise called history, a discipline which still bears the name he gave it. His critics should also bear in mind it's only because Herodotus set us on this path that we can even scorn his methods in the first place. To this most uncommon "common man," we owe an enormous collective debt.</span>
