Answer:
The answer is: letter c, density.
Explanation:
Gold is a chemical element that is <em>very rare.</em> It has a high atomic number and is represented by the symbol "Au."
The problem above is asking about the physical property of gold that will help you determine whether a shiny gold nugget is, indeed, real gold. Remember that you are hiking and not anywhere else in the world.
If you look at choice a, appearance. This is definitely incorrect because looking at the object will not be able to help you verify whether it is true gold or "fool's gold." Considering melting point (letter b) would also be hard because you will be needing the necessary equipment to melt gold. Gold melts at 1,064 degrees Celsius. So,this sounds very impractical. (thus, melting point is incorrect) Now, if you look at letter d, physical state, it goes the same way with appearance. It will only tell you that the object is solid and that's it.
Letter c, density is the answer because if you analyze the density of gold, which is 19.32 grams per cubic meter, it is far from the density of iron pyrite (fool's gold) which is 4.8-5 grams per cubic meter. This means that gold is denser or heavier than iron pyrite. You will definitely be able to tell which such big gap in their densities.
I think it is <span>Alpha rays.</span>
Answer:
Explanation:
Heat energy naturally transfers from a high temperature substance to a low temperature substance.
It is not a statement or direct application of the second law of thermodynamics.
The change in internal energy of a system can be found by combining the heat energy added to a system minus the work done by the system.
It is not a statement or direct application of the second law of thermodynamics. This statement is in accordance with first law of thermodynamics.
All the other two statements are in accordance with second law of thermodynamics.
<span>Astatine is the limited element found in the Earth's crust. This element is the rarest one found in the crust and it is radioactive. It is named after the Greek word "astatos" which means unstable. The first acknowledgement of it, came in 1940, which was when it was declared.</span>
